1.From Tadashi Saito's advice

to_parts changed to split,assign removed, ** added,bugs in infinite? & nozero? fixed. 2.Rounding functionalities added mode now accepts rounding mode. round accepts second argument for Bankers' rounding. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@4008 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
author: shigek <shigek@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> 2003-06-27 04:38:57 +0000
committer: shigek <shigek@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> 2003-06-27 04:38:57 +0000
commit: d3ce235babf3a5fa9a7904c45ec193e8962fe845 (patch)
tree: 6d2a550cb79cddaee7a52a6aae149d1b3f0d3c16 /ext/bigdecimal
parent: 7e91b4b546634afa0203f7bd6d0e5092f8f7ee61 (diff)
4 files changed, 740 insertions, 614 deletions
diff --git a/ext/bigdecimal/bigdecimal.c b/ext/bigdecimal/bigdecimal.c
index 62343830ac..f1bd1e2320 100644
--- a/ext/bigdecimal/bigdecimal.c
+++ b/ext/bigdecimal/bigdecimal.c
@@ -34,14 +34,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#ifdef NT
-#include <malloc.h>
-#ifdef _MSC_VER
-#include <float.h>
-#define isnan(x) _isnan(x)
-#define isinf(x) (!(_finite(x)))
-#endif /* _MSC_VER */
-#endif /* defined NT */
 #include "ruby.h"
 #include "math.h"
 #include "version.h"
@@ -52,7 +44,7 @@ VALUE rb_cBigDecimal;
 
 #include "bigdecimal.h"
 
-/* MACRO's to guard objects from GC by keeping it in stack */
+/* MACRO's to guard objects from GC by keeping them in stack */
 #define ENTER(n) volatile VALUE vStack[n];int iStack=0
 #define PUSH(x)  vStack[iStack++] = (unsigned long)(x);
 #define SAVE(p)  PUSH(p->obj);
@@ -71,7 +63,9 @@ static int VpSubAbs(Real *a,Real *b,Real *c);
 static U_LONG VpSetPTR(Real *a,Real *b,Real *c,U_LONG *a_pos,U_LONG *b_pos,U_LONG *c_pos,U_LONG *av,U_LONG *bv);
 static int VpNmlz(Real *a);
 static void VpFormatSt(char *psz,S_INT fFmt);
-static int VpRdup(Real *m);
+static int VpRdup(Real *m,U_LONG ind_m);
+static int VpInternalRound(Real *c,int ixDigit,U_LONG vPrev,U_LONG v);
+
 static U_LONG SkipWhiteChar(char *szVal);
 
 /*
@@ -297,25 +291,32 @@ BigDecimal_load(VALUE self, VALUE str)
 static VALUE
 BigDecimal_mode(VALUE self, VALUE which, VALUE val)
 {
-    unsigned short fo = VpGetException();
-    unsigned short f;
-
-    if(TYPE(which)!=T_FIXNUM)  return INT2FIX(fo);
-    if(val!=Qfalse && val!=Qtrue) return INT2FIX(fo);
+    unsigned long f,fo;
+ 
+    if(TYPE(which)!=T_FIXNUM)     return Qnil;
+    f = (unsigned long)FIX2INT(which);
 
-    f = (unsigned short)FIX2INT(which);
-    if(f&VP_EXCEPTION_INFINITY) {
+	if(f&VP_EXCEPTION_ALL) {
+        /* Exception mode setting */
         fo = VpGetException();
-        VpSetException((unsigned short)((val==Qtrue)?(fo|VP_EXCEPTION_INFINITY):
-                         (fo&(~VP_EXCEPTION_INFINITY))));
+        if(val!=Qfalse && val!=Qtrue) return Qnil;
+        if(f&VP_EXCEPTION_INFINITY) {
+            VpSetException((unsigned short)((val==Qtrue)?(fo|VP_EXCEPTION_INFINITY):
+                           (fo&(~VP_EXCEPTION_INFINITY))));
+        }
+        if(f&VP_EXCEPTION_NaN) {
+            VpSetException((unsigned short)((val==Qtrue)?(fo|VP_EXCEPTION_NaN):
+                           (fo&(~VP_EXCEPTION_NaN))));
+        }
+        return INT2FIX(fo);
     }
-    if(f&VP_EXCEPTION_NaN) {
-        fo = VpGetException();
-        VpSetException((unsigned short)((val==Qtrue)?(fo|VP_EXCEPTION_NaN):
-                         (fo&(~VP_EXCEPTION_NaN))));
+    if(VP_COMP_MODE==f) {
+        /* Computaion mode setting */
+        if(TYPE(val)!=T_FIXNUM)     return Qnil;
+        fo = VpSetCompMode((unsigned long)FIX2INT(val));
+        return INT2FIX(fo);
     }
-    fo = VpGetException();
-    return INT2FIX(fo);
+    return Qnil;
 }
 
 static U_LONG
@@ -380,8 +381,9 @@ static VALUE
 BigDecimal_IsInfinite(VALUE self)
 {
     Real *p = GetVpValue(self,1);
-    if(VpIsInf(p)) return Qtrue;
-    return Qfalse;
+    if(VpIsPosInf(p)) return INT2FIX(1);
+    if(VpIsNegInf(p)) return INT2FIX(-1);
+    return Qnil;
 }
 
 static VALUE
@@ -547,7 +549,7 @@ static VALUE
 BigDecimal_nonzero(VALUE self)
 {
     Real *a = GetVpValue(self,1);
-    return VpIsZero(a) ? Qfalse : self;
+    return VpIsZero(a) ? Qnil : self;
 }
 
 static VALUE
@@ -650,6 +652,7 @@ BigDecimal_mult(VALUE self, VALUE r)
 
 static VALUE
 BigDecimal_divide(Real **c, Real **res, Real **div, VALUE self, VALUE r)
+/* For c,res = self.div(r): no round operation */
 {
     ENTER(5);
     Real *a, *b;
@@ -669,16 +672,19 @@ BigDecimal_divide(Real **c, Real **res, Real **div, VALUE self, VALUE r)
 
 static VALUE
 BigDecimal_div(VALUE self, VALUE r)
+/* For c = self/r: with round operation */
 {
     ENTER(5);
     Real *c=NULL, *res=NULL, *div = NULL;
     r = BigDecimal_divide(&c, &res, &div, self, r);
     SAVE(c);SAVE(res);SAVE(div);
     if(r!=(VALUE)0) return r; /* coerced by other */
-    if(res->frac[0]*2>=div->frac[0]) {
-        /* Round up */
-        VpRdup(c);
-    }
+    /* a/b = c + r/b */
+    /* c xxxxx
+       r 00000yyyyy  ==> (y/b)*BASE >= HALF_BASE
+     */
+    /* Round up ? */
+    VpInternalRound(c,0,c->frac[c->Prec-1],(VpBaseVal()*res->frac[0])/div->frac[0]);
     return ToValue(c);
 }
 
@@ -707,7 +713,7 @@ BigDecimal_DoDivmod(VALUE self, VALUE r, Real **div, Real **mod)
     VpDivd(c, res, a, b);
     mx = c->Prec *(VpBaseFig() + 1);
     GUARD_OBJ(d,VpCreateRbObject(mx, "0"));
-    VpRound(d,c,1,3,0);
+    VpActiveRound(d,c,VP_COMP_MODE_FLOOR,0);
     VpMult(res,d,b);
     VpAddSub(c,a,res,-1);
     *div = d;
@@ -754,7 +760,7 @@ BigDecimal_divremain(VALUE self, VALUE r, Real **dv, Real **rv)
     GUARD_OBJ(d,VpCreateRbObject(mx, "0"));
     GUARD_OBJ(f,VpCreateRbObject(mx, "0"));
 
-    VpRound(d,c,1,1,0); /* 1: round off */
+    VpActiveRound(d,c,VP_COMP_MODE_TRUNCATE,0); /* 0: round off */
 
     VpFrac(f, c);
     VpMult(rr,f,b);
@@ -814,20 +820,6 @@ BigDecimal_divmod2(VALUE self, VALUE b, VALUE n)
 }
 
 static VALUE
-BigDecimal_assign2(VALUE self, VALUE n, VALUE f)
-{
-    ENTER(5);
-    Real *cv;
-    Real *av;
-    U_LONG mx = (U_LONG)GetPositiveInt(n);
-    Check_Type(f, T_FIXNUM);
-    GUARD_OBJ(cv,VpCreateRbObject(mx,"0"));
-    GUARD_OBJ(av,GetVpValue(self,1));
-    VpAsgn(cv,av,FIX2INT(f));
-    return ToValue(cv);
-}
-
-static VALUE
 BigDecimal_add2(VALUE self, VALUE b, VALUE n)
 {
     ENTER(5);
@@ -928,7 +920,7 @@ BigDecimal_fix(VALUE self)
     GUARD_OBJ(a,GetVpValue(self,1));
     mx = a->Prec *(VpBaseFig() + 1);
     GUARD_OBJ(c,VpCreateRbObject(mx, "0"));
-    VpRound(c,a,1,1,0); /* 1: round off */
+    VpActiveRound(c,a,VP_COMP_MODE_TRUNCATE,0); /* 0: round off */
     return ToValue(c);
 }
 
@@ -941,19 +933,29 @@ BigDecimal_round(int argc, VALUE *argv, VALUE self)
     int sw;
     U_LONG mx;
     VALUE vLoc;
-
-    if(rb_scan_args(argc,argv,"01",&vLoc)==0) {
+    VALUE vBanker;
+    int na = rb_scan_args(argc,argv,"02",&vLoc,&vBanker);
+    sw = VP_COMP_MODE_ROUNDUP; /* round up */
+    switch(na) {
+    case 0:
         iLoc = 0;
-    } else {
+        break;
+    case 1:
+        Check_Type(vLoc, T_FIXNUM);
+        iLoc = FIX2INT(vLoc);
+        break;
+    case 2:
         Check_Type(vLoc, T_FIXNUM);
         iLoc = FIX2INT(vLoc);
+        Check_Type(vBanker, T_FIXNUM);
+        if(FIX2INT(vBanker)) sw = VP_COMP_MODE_EVEN; /* Banker's rounding */
+        break;
     }
-    sw = 2;
 
     GUARD_OBJ(a,GetVpValue(self,1));
     mx = a->Prec *(VpBaseFig() + 1);
     GUARD_OBJ(c,VpCreateRbObject(mx, "0"));
-    VpRound(c,a,sw,1,iLoc);
+    VpActiveRound(c,a,sw,iLoc);
     return ToValue(c);
 }
 
@@ -973,12 +975,11 @@ BigDecimal_truncate(int argc, VALUE *argv, VALUE self)
         Check_Type(vLoc, T_FIXNUM);
         iLoc = FIX2INT(vLoc);
     }
-    sw = 1; /* truncate */
 
     GUARD_OBJ(a,GetVpValue(self,1));
     mx = a->Prec *(VpBaseFig() + 1);
     GUARD_OBJ(c,VpCreateRbObject(mx, "0"));
-    VpRound(c,a,sw,1,iLoc);
+    VpActiveRound(c,a,VP_COMP_MODE_TRUNCATE,iLoc); /* 0: truncate */
     return ToValue(c);
 }
 
@@ -1015,7 +1016,7 @@ BigDecimal_floor(int argc, VALUE *argv, VALUE self)
     GUARD_OBJ(a,GetVpValue(self,1));
     mx = a->Prec *(VpBaseFig() + 1);
     GUARD_OBJ(c,VpCreateRbObject(mx, "0"));
-    VpRound(c,a,1,3,iLoc);
+    VpActiveRound(c,a,VP_COMP_MODE_FLOOR,iLoc);
     return ToValue(c);
 }
 
@@ -1038,7 +1039,7 @@ BigDecimal_ceil(int argc, VALUE *argv, VALUE self)
     GUARD_OBJ(a,GetVpValue(self,1));
     mx = a->Prec *(VpBaseFig() + 1);
     GUARD_OBJ(c,VpCreateRbObject(mx, "0"));
-    VpRound(c,a,1,2,iLoc);
+    VpActiveRound(c,a,VP_COMP_MODE_CEIL,iLoc);
     return ToValue(c);
 }
 
@@ -1064,7 +1065,7 @@ BigDecimal_to_s(int argc, VALUE *argv, VALUE self)
 }
 
 static VALUE
-BigDecimal_to_parts(VALUE self)
+BigDecimal_split(VALUE self)
 {
     ENTER(5);
     Real *vp;
@@ -1366,8 +1367,10 @@ Init_bigdecimal(void)
     rb_define_singleton_method(rb_cBigDecimal, "induced_from",BigDecimal_induced_from, 1);
     rb_define_singleton_method(rb_cBigDecimal, "_load", BigDecimal_load, 1);
 
-    /* Constants */
+    /* Constants definition */
     rb_define_const(rb_cBigDecimal, "BASE", INT2FIX((S_INT)VpBaseVal()));
+
+    /* Exceptions */
     rb_define_const(rb_cBigDecimal, "EXCEPTION_ALL",INT2FIX(VP_EXCEPTION_ALL));
     rb_define_const(rb_cBigDecimal, "EXCEPTION_NaN",INT2FIX(VP_EXCEPTION_NaN));
     rb_define_const(rb_cBigDecimal, "EXCEPTION_INFINITY",INT2FIX(VP_EXCEPTION_INFINITY));
@@ -1375,6 +1378,14 @@ Init_bigdecimal(void)
     rb_define_const(rb_cBigDecimal, "EXCEPTION_OVERFLOW",INT2FIX(VP_EXCEPTION_OVERFLOW));
     rb_define_const(rb_cBigDecimal, "EXCEPTION_ZERODIVIDE",INT2FIX(VP_EXCEPTION_ZERODIVIDE));
 
+    /* Computation mode */
+    rb_define_const(rb_cBigDecimal, "COMP_MODE",INT2FIX(VP_COMP_MODE));
+    rb_define_const(rb_cBigDecimal, "COMP_MODE_TRUNCATE",INT2FIX(VP_COMP_MODE_TRUNCATE));
+    rb_define_const(rb_cBigDecimal, "COMP_MODE_ROUNDUP",INT2FIX(VP_COMP_MODE_ROUNDUP));
+    rb_define_const(rb_cBigDecimal, "COMP_MODE_CEIL",INT2FIX(VP_COMP_MODE_CEIL));
+    rb_define_const(rb_cBigDecimal, "COMP_MODE_FLOOR",INT2FIX(VP_COMP_MODE_FLOOR));
+    rb_define_const(rb_cBigDecimal, "COMP_MODE_EVEN",INT2FIX(VP_COMP_MODE_EVEN));
+
     /* Constants for sign value */
     rb_define_const(rb_cBigDecimal, "SIGN_NaN",INT2FIX(VP_SIGN_NaN));
     rb_define_const(rb_cBigDecimal, "SIGN_POSITIVE_ZERO",INT2FIX(VP_SIGN_POSITIVE_ZERO));
@@ -1386,7 +1397,6 @@ Init_bigdecimal(void)
 
     /* instance methods */
     rb_define_method(rb_cBigDecimal, "prec", BigDecimal_prec, 0);
-    rb_define_method(rb_cBigDecimal, "assign", BigDecimal_assign2, 2);
     rb_define_method(rb_cBigDecimal, "add", BigDecimal_add2, 2);
     rb_define_method(rb_cBigDecimal, "sub", BigDecimal_sub2, 2);
     rb_define_method(rb_cBigDecimal, "mult", BigDecimal_mult2, 2);
@@ -1394,7 +1404,7 @@ Init_bigdecimal(void)
     rb_define_method(rb_cBigDecimal, "hash", BigDecimal_hash, 0);
     rb_define_method(rb_cBigDecimal, "to_s", BigDecimal_to_s, -1);
     rb_define_method(rb_cBigDecimal, "to_i", BigDecimal_to_i, 0);
-    rb_define_method(rb_cBigDecimal, "to_parts", BigDecimal_to_parts, 0);
+    rb_define_method(rb_cBigDecimal, "split", BigDecimal_split, 0);
     rb_define_method(rb_cBigDecimal, "+", BigDecimal_add, 1);
     rb_define_method(rb_cBigDecimal, "-", BigDecimal_sub, 1);
     rb_define_method(rb_cBigDecimal, "+@", BigDecimal_uplus, 0);
@@ -1415,6 +1425,7 @@ Init_bigdecimal(void)
     rb_define_method(rb_cBigDecimal, "floor", BigDecimal_floor, -1);
     rb_define_method(rb_cBigDecimal, "ceil", BigDecimal_ceil, -1);
     rb_define_method(rb_cBigDecimal, "power", BigDecimal_power, 1);
+    rb_define_method(rb_cBigDecimal, "**", BigDecimal_power, 1);
     rb_define_method(rb_cBigDecimal, "exp", BigDecimal_exp, 1);
     rb_define_method(rb_cBigDecimal, "sincos", BigDecimal_sincos, 1);
     rb_define_method(rb_cBigDecimal, "<=>", BigDecimal_comp, 1);
@@ -1462,6 +1473,8 @@ static int gfCheckVal = 1;      /* Value checking flag in VpNmlz()  */
 #endif /* _DEBUG */
 
 static U_LONG gnPrecLimit = 0;  /* Global upper limit of the precision newly allocated */
+static short  gfCompMode  = VP_COMP_MODE_ROUNDUP; /* Mode for general computation */
+
 static U_LONG BASE_FIG = 4;     /* =log10(BASE)  */
 static U_LONG BASE = 10000L;    /* Base value(value must be 10**BASE_FIG) */
                 /* The value of BASE**2 + BASE must be represented */
@@ -1544,6 +1557,22 @@ VpSetPrecLimit(U_LONG n)
     return s;
 }
 
+VP_EXPORT unsigned long
+VpGetCompMode(void)
+{
+    return gfCompMode;
+}
+
+VP_EXPORT unsigned long
+VpSetCompMode(unsigned long n)
+{
+    unsigned long s = gfCompMode;
+    if(n!=VP_COMP_MODE_TRUNCATE && n!= VP_COMP_MODE_ROUNDUP && n!=VP_COMP_MODE_CEIL &&
+       n!=VP_COMP_MODE_FLOOR    && n!= VP_COMP_MODE_EVEN)  return s;
+    gfCompMode = n;
+    return s;
+}
+
 /*
  *  0.0 & 1.0 generator
  *    These gZero_..... and gOne_..... can be any name
@@ -1552,8 +1581,8 @@ VpSetPrecLimit(U_LONG n)
  *    (to let the compiler know they may be changed in outside
  *    (... but not actually..)).
  */
-double gZero_ABCED9B1_CE73__00400511F31D = 0.0;
-double gOne_ABCED9B4_CE73__00400511F31D  = 1.0;
+volatile double gZero_ABCED9B1_CE73__00400511F31D = 0.0;
+volatile double gOne_ABCED9B4_CE73__00400511F31D  = 1.0;
 static double
 Zero(void)
 {
@@ -1969,10 +1998,10 @@ VpAlloc(U_LONG mx, char *szVal)
         ++i;
         ++ni;
     }
-    nf = 0;
+    nf  = 0;
     ipf = 0;
     ipe = 0;
-    ne = 0;
+    ne  = 0;
     if(v) {
         /* other than digit nor \0 */
         if(szVal[i] == '.') {    /* xxx. */
@@ -2023,11 +2052,10 @@ VpAlloc(U_LONG mx, char *szVal)
  * [Input]
  *   a   ... RHSV
  *   isw ... switch for assignment.
- *    c = a  when isw =  1 or 2
- *    c = -a when isw = -1 or -1
- *    when |isw|==1
- *    if c->MaxPrec < a->Prec,then round up
- *    will not be performed.
+ *    c = a  when isw > 0
+ *    c = -a when isw < 0
+ *    if c->MaxPrec < a->Prec,then round operation
+ *    will be performed.
  * [Output]
  *  c  ... LHSV
  */
@@ -2051,22 +2079,19 @@ VpAsgn(Real *c, Real *a, int isw)
         n =(a->Prec < c->MaxPrec) ?(a->Prec) :(c->MaxPrec);
         c->Prec = n;
         for(j=0;j < n; ++j) c->frac[j] = a->frac[j];
-        if(isw < 0) isw = -isw;
-        if(isw == 2) {
-            if(a->MaxPrec>n) {
-                if((c->Prec < a->Prec) &&
-                   (a->frac[n] >= HALF_BASE)) VpRdup(c);    /* round up/off */
-            }
+        /* Needs round ? */
+        if(c->Prec < a->Prec) {
+            VpInternalRound(c,n,(n>0)?a->frac[n-1]:0,a->frac[n]);
         }
     } else {
         /* The value of 'a' is zero.  */
         VpSetZero(c,isw*VpGetSign(a));
         return 1;
     }
-    VpNmlz(c);
     return c->Prec*BASE_FIG;
 }
 
+
 /*
  *   c = a + b  when operation =  1 or 2
  *  = a - b  when operation = -1 or -2.
@@ -2113,7 +2138,7 @@ VpAddSub(Real *c, Real *a, Real *b, int operation)
     }
 
     if(operation < 0) sw = -1;
-    else     sw =  1;
+    else              sw =  1;
 
     /* compare absolute value. As a result,|a_ptr|>=|b_ptr| */
     if(a->exponent > b->exponent) {
@@ -2202,7 +2227,6 @@ static int
 VpAddAbs(Real *a, Real *b, Real *c)
 {
     U_LONG word_shift;
-    U_LONG round;
     U_LONG carry;
     U_LONG ap;
     U_LONG bp;
@@ -2210,7 +2234,7 @@ VpAddAbs(Real *a, Real *b, Real *c)
     U_LONG a_pos;
     U_LONG b_pos;
     U_LONG c_pos;
-    U_LONG av, bv;
+    U_LONG av, bv, mrv;
 
 #ifdef _DEBUG
     if(gfDebug) {
@@ -2226,7 +2250,7 @@ VpAddAbs(Real *a, Real *b, Real *c)
     if(word_shift==-1L) return 0; /* Overflow */
     if(b_pos == -1L) goto Assign_a;
 
-    round =((av + bv) >= HALF_BASE) ? 1 : 0;
+    mrv = av + bv; /* Most right val. Used for round. */
 
     /* Just assign the last few digits of b to c because a has no  */
     /* corresponding digits to be added. */
@@ -2281,8 +2305,7 @@ VpAddAbs(Real *a, Real *b, Real *c)
     }
     if(c_pos) c->frac[c_pos - 1] += carry;
 
-    if(round) VpRdup(c);        /* Roundup and normalize. */
-    else       VpNmlz(c);        /* normalize the result */
+    if(!VpInternalRound(c,0,(c->Prec>0)?a->frac[c->Prec-1]:0,mrv)) VpNmlz(c);
     goto Exit;
 
 Assign_a:
@@ -2305,7 +2328,7 @@ static int
 VpSubAbs(Real *a, Real *b, Real *c)
 {
     U_LONG word_shift;
-    U_LONG round;
+    U_LONG mrv;
     U_LONG borrow;
     U_LONG ap;
     U_LONG bp;
@@ -2330,10 +2353,10 @@ VpSubAbs(Real *a, Real *b, Real *c)
     if(b_pos == -1L) goto Assign_a;
 
     if(av >= bv) {
-        round =((av -= bv) >= HALF_BASE) ? 1 : 0;
+        mrv = av - bv;
         borrow = 0;
     } else {
-        round = 0;
+        mrv    = 0;
         borrow = 1;
     }
 
@@ -2395,8 +2418,8 @@ VpSubAbs(Real *a, Real *b, Real *c)
         }
     }
     if(c_pos) c->frac[c_pos - 1] -= borrow;
-    if(round) VpRdup(c);        /* Round up and normalize */
-    else   VpNmlz(c);        /* normalize the result */
+
+    if(!VpInternalRound(c,0,(c->Prec>0)?a->frac[c->Prec-1]:0,mrv)) VpNmlz(c);
     goto Exit;
 
 Assign_a:
@@ -2454,7 +2477,7 @@ VpSetPTR(Real *a, Real *b, Real *c, U_LONG *a_pos, U_LONG *b_pos, U_LONG *c_pos,
             /*
              *   a =  xxxxxxAxxx
              *   c =  xxxxxx
-             *  a_pos =  |
+             *   a_pos =    |
              */
             *a_pos = left_word;
             *av = a->frac[*a_pos];    /* av is 'A' shown in above. */
@@ -2544,11 +2567,11 @@ VpMult(Real *c, Real *a, Real *b)
         return 1; /* 0: 1 significant digit */
     }
 
-    if((a->Prec == 1) &&(a->frac[0] == 1) &&(a->exponent == 1)) {
+    if(VpIsOne(a)) {
         VpAsgn(c, b, VpGetSign(a));
         goto Exit;
     }
-    if((b->Prec == 1) &&(b->frac[0] == 1) &&(b->exponent == 1)) {
+    if(VpIsOne(b)) {
         VpAsgn(c, a, VpGetSign(b));
         goto Exit;
     }
@@ -2624,7 +2647,7 @@ VpMult(Real *c, Real *a, Real *b)
 
     VpNmlz(c);            /* normalize the result */
     if(w != NULL) {        /* free work variable */
-        VpAsgn(w, c, 2);
+        VpAsgn(w, c, 1);
         VpFree(c);
         c = w;
     }
@@ -2675,8 +2698,7 @@ VpDivd(Real *c, Real *r, Real *a, Real *b)
         VpSetZero(r,VpGetSign(a)*VpGetSign(b));
         goto Exit;
     }
-
-    if((b->Prec == 1) &&(b->frac[0] == 1) &&(b->exponent == 1)) {
+    if(VpIsOne(b)) {
         /* divide by one  */
         VpAsgn(c, a, VpGetSign(b));
         VpSetZero(r,VpGetSign(a));
@@ -2980,6 +3002,7 @@ Exit:
     return (int)val;
 }
 
+#ifdef _DEBUG
 /*
  *    cntl_chr ... ASCIIZ Character, print control characters
  *     Available control codes:
@@ -3082,6 +3105,7 @@ VPrint(FILE *fp, char *cntl_chr, Real *a)
     }
     return (int)nc;
 }
+#endif /* _DEBUG */
 
 static void
 VpFormatSt(char *psz,S_INT fFmt)
@@ -3468,8 +3492,9 @@ VpDtoV(Real *m, double d)
     }
     m->Prec = ind_m + 1;
     m->exponent = ne;
-    if(val*((double)((S_INT)BASE)) >=(double)((S_INT)HALF_BASE)) VpRdup(m);
-    VpNmlz(m);
+
+    if(!VpInternalRound(m,0,(m->Prec>0)?m->frac[m->Prec-1]:0,
+                      (U_LONG)(val*((double)((S_INT)BASE))))) VpNmlz(m);
 
 Exit:
 #ifdef _DEBUG
@@ -3551,8 +3576,8 @@ VpSqrt(Real *y, Real *x)
     Real *f = NULL;
     Real *r = NULL;
     S_LONG y_prec, f_prec;
-	S_LONG n;
-	S_LONG e;
+    S_LONG n;
+    S_LONG e;
     S_LONG prec;
     S_LONG nr;
     double val;
@@ -3650,11 +3675,12 @@ Exit:
 
 /*
  *
- * f = 1: round, 2:ceil, 3: floor
+ * f = 0: Round off/Truncate, 1: round up, 2:ceil, 3: floor, 4: Banker's rounding
+ * nf: digit position for operation.
  *
  */
 VP_EXPORT void
-VpRound(Real *y, Real *x, int sw, int f, int nf)
+VpActiveRound(Real *y, Real *x, int f, int nf)
 {
     int n,i,j,ix,ioffset;
     U_LONG v;
@@ -3665,35 +3691,41 @@ VpRound(Real *y, Real *x, int sw, int f, int nf)
         goto Exit;
     }
 
-    /* First,assign whole value */
-    VpAsgn(y, x, sw);
+    /* First,assign whole value in truncation mode */
+    VpAsgn(y, x, 1); /* 1 round off,2 round up */
     nf += y->exponent*((int)BASE_FIG);
     /* ix: x->fraq[ix] contains round position */
     ix = (nf + ((int)BASE_FIG))/((int)BASE_FIG)-1;
     if(ix<0 || ((U_LONG)ix)>=y->Prec) goto Exit; /* Unable to round */
     ioffset = nf - ix*((int)BASE_FIG);
     for(j=ix+1;j<(int)y->Prec;++j) y->frac[j] = 0;
-    VpNmlz(y);
+    /* VpNmlz(y); */
     v = y->frac[ix];
     /* drop digits after pointed digit */
     n = BASE_FIG - ioffset - 1;
     for(i=0;i<n;++i) v /= 10;
     div = v/10;
     v = v - div*10;
-    switch(f){
-    case 1: /* Round */
-        if(sw==2 && v>=5) {
-            ++div;
-        }
+    switch(f) {
+    case VP_COMP_MODE_TRUNCATE: /* Truncate/Round off */
+         break;
+    case VP_COMP_MODE_ROUNDUP: /* Round up  */
+        if(v>=5) ++div;
         break;
-    case 2: /* ceil */
-        if(v) {
-            if(VpGetSign(x)>0) ++div;
-        }
+    case VP_COMP_MODE_CEIL: /* ceil */
+        if(v && (VpGetSign(x)>0)) ++div;
+        break;
+    case VP_COMP_MODE_FLOOR: /* floor */
+        if(v && (VpGetSign(x)<0)) ++div;
         break;
-    case 3: /* floor */
-        if(v) {
-            if(VpGetSign(x)<0) ++div;
+    case VP_COMP_MODE_EVEN: /* Banker's rounding */
+        if(v>5) ++div;
+        else if(v==5) {
+            if(i==(BASE_FIG-1)) {
+                if(ix && (y->frac[ix-1]%2)) ++div;
+            } else {
+                if(div%2) ++div;
+            }
         }
         break;
     }
@@ -3702,7 +3734,7 @@ VpRound(Real *y, Real *x, int sw, int f, int nf)
         y->frac[ix] = 0;
         if(ix) {
             VpNmlz(y);
-            VpRdup(y);
+            VpRdup(y,0);
         } else {
             VpSetOne(y);
             VpSetSign(y,VpGetSign(x));
@@ -3715,24 +3747,51 @@ VpRound(Real *y, Real *x, int sw, int f, int nf)
 Exit:
 #ifdef _DEBUG
     if(gfDebug) {
-        VPrint(stdout, "VpRound y=%\n", y);
+        VPrint(stdout, "VpActiveRound y=%\n", y);
         VPrint(stdout, "  x=%\n", x);
     }
 #endif /*_DEBUG */
     return;
 }
 
+static int 
+VpInternalRound(Real *c,int ixDigit,U_LONG vPrev,U_LONG v)
+{
+    int f = 0;
+    v /= BASE1;
+    switch(gfCompMode) {
+    case VP_COMP_MODE_TRUNCATE:
+        break;
+    case VP_COMP_MODE_ROUNDUP:
+        if(v >= 5)               f = 1;
+        break;
+    case VP_COMP_MODE_CEIL: /* ceil */
+        if(v && (VpGetSign(c)>0)) f = 1;
+        break;
+    case VP_COMP_MODE_FLOOR: /* floor */
+        if(v && (VpGetSign(c)<0)) f = 1;
+        break;
+    case VP_COMP_MODE_EVEN: /* Banker's rounding */
+        if(v>5) f = 1;
+        else if(v==5 && vPrev%2)  f = 1;
+        break;
+    }
+    if(f) VpRdup(c,ixDigit);    /* round up */
+    return f;
+}
+
 /*
  *  Rounds up m(plus one to final digit of m).
  */
 static int
-VpRdup(Real *m)
+VpRdup(Real *m,U_LONG ind_m)
 {
-    U_LONG ind_m, carry;
-    ind_m = m->Prec;
+    U_LONG carry;
+
+    if(!ind_m) ind_m = m->Prec;
+
     carry = 1;
-    while(carry > 0 && ind_m) {
-        --ind_m;
+    while(carry > 0 && (ind_m--)) {
         m->frac[ind_m] += carry;
         if(m->frac[ind_m] >= BASE) m->frac[ind_m] -= BASE;
         else                       carry = 0;
@@ -3907,8 +3966,8 @@ VpPi(Real *y)
         VpAddSub(r, y, f, 1);  /* r = y + f   */
         VpAsgn(y, r, 1);       /* y = r    */
 
-        VpRdup(n);            /* n   = n + 1 */
-        VpRdup(n);            /* n   = n + 1 */
+        VpRdup(n,0);            /* n   = n + 1 */
+        VpRdup(n,0);            /* n   = n + 1 */
         if(VpIsZero(f)) break;
     } while((f->exponent > 0 ||    ((U_LONG)(-(f->exponent)) < y->MaxPrec)) &&
             i1<nc
@@ -3926,8 +3985,8 @@ VpPi(Real *y)
         VpAddSub(r, y, f, 1); /* r = y + f   */
 
         VpAsgn(y, r, 1);      /* y = r    */
-        VpRdup(n);           /* n   = n + 1  */
-        VpRdup(n);           /* n   = n + 1 */
+        VpRdup(n,0);           /* n   = n + 1  */
+        VpRdup(n,0);           /* n   = n + 1 */
         if(VpIsZero(f)) break;
     } while((f->exponent > 0 || ((U_LONG)(-(f->exponent)) < y->MaxPrec)) &&
             i2<nc
@@ -3972,11 +4031,11 @@ VpExp1(Real *y)
     add = VpAlloc(p, "#1");    /* add = 1 */
 
     VpSetOne(y);            /* y   = 1 */
-    VpRdup(y);            /* y   = y + 1  */
+    VpRdup(y,0);            /* y   = y + 1  */
     i = 0;
     do {
         ++i;
-        VpRdup(n);        /* n   = n + 1  */
+        VpRdup(n,0);        /* n   = n + 1  */
         VpDivd(f, r, add, n);    /* f   = add/n(=1/n!)  */
         VpAsgn(add, f, 1);    /* add = 1/n!  */
         VpAddSub(r, y, f, 1);
@@ -4041,7 +4100,7 @@ VpExp(Real *y, Real *x)
     i = 0;
     do {
         ++i;
-        VpRdup(n);        /* n   = n + 1  */
+        VpRdup(n,0);        /* n   = n + 1  */
         VpDivd(div, r, x, n);    /* div = x/n */
         VpMult(c, z, div);    /* c   = x/(n-1)! * x/n */
         VpAsgn(z, c, 1);    /* z   = x*n/n! */
@@ -4117,7 +4176,7 @@ VpSinCos(Real *psin,Real *pcos,Real *x)
     i = 0;
     do {
         ++i;
-        VpRdup(n);        /* n   = n + 1  */
+        VpRdup(n,0);        /* n   = n + 1  */
         VpDivd(div, r, x, n);    /* div = x/n */
         VpMult(c, z, div);    /* c   = x/(n-1)! * x/n */
         VpAsgn(z, c, 1);    /* z   = x*n/n! */
diff --git a/ext/bigdecimal/bigdecimal.h b/ext/bigdecimal/bigdecimal.h
index 8708d04b6f..3debb52826 100644
--- a/ext/bigdecimal/bigdecimal.h
+++ b/ext/bigdecimal/bigdecimal.h
@@ -32,7 +32,7 @@ extern "C" {
 #define S_INT  int
 
 /* Exception codes */
-#define VP_EXCEPTION_ALL        ((unsigned short)0xFFFF)
+#define VP_EXCEPTION_ALL        ((unsigned short)0x00FF)
 #define VP_EXCEPTION_INFINITY   ((unsigned short)0x0001)
 #define VP_EXCEPTION_NaN        ((unsigned short)0x0002)
 #define VP_EXCEPTION_UNDERFLOW  ((unsigned short)0x0004)
@@ -43,6 +43,14 @@ extern "C" {
 #define VP_EXCEPTION_OP         ((unsigned short)0x0020)
 #define VP_EXCEPTION_MEMORY     ((unsigned short)0x0040)
 
+/* Computation mode */
+#define VP_COMP_MODE            ((unsigned short)0x0100)
+#define VP_COMP_MODE_TRUNCATE   0
+#define VP_COMP_MODE_ROUNDUP    1
+#define VP_COMP_MODE_CEIL       2
+#define VP_COMP_MODE_FLOOR      3
+#define VP_COMP_MODE_EVEN       4
+
 #define VP_SIGN_NaN                0 /* NaN                      */
 #define VP_SIGN_POSITIVE_ZERO      1 /* Positive zero            */
 #define VP_SIGN_NEGATIVE_ZERO     -1 /* Negative zero            */
@@ -103,6 +111,10 @@ VP_EXPORT double VpGetDoubleNegZero(void);
 VP_EXPORT U_LONG VpGetPrecLimit(void);
 VP_EXPORT U_LONG VpSetPrecLimit(U_LONG n);
 
+/* Computation mode */
+VP_EXPORT unsigned long VpGetCompMode(void);
+VP_EXPORT unsigned long VpSetCompMode(unsigned long n);
+
 VP_EXPORT int VpException(unsigned short f,char *str,int always);
 VP_EXPORT int VpIsNegDoubleZero(double v);
 VP_EXPORT U_LONG VpNumOfChars(Real *vp);
@@ -123,14 +135,13 @@ VP_EXPORT void VpVtoD(double *d,S_LONG *e,Real *m);
 VP_EXPORT void VpDtoV(Real *m,double d);
 VP_EXPORT void VpItoV(Real *m,S_INT ival);
 VP_EXPORT int VpSqrt(Real *y,Real *x);
-VP_EXPORT void VpRound(Real *y,Real *x,int sw,int f,int il);
+VP_EXPORT void VpActiveRound(Real *y,Real *x,int f,int il);
 VP_EXPORT void VpFrac(Real *y,Real *x);
 VP_EXPORT int VpPower(Real *y,Real *x,S_INT n);
 VP_EXPORT void VpPi(Real *y);
 VP_EXPORT void VpExp1(Real *y);
 VP_EXPORT void VpExp(Real *y,Real *x);
 VP_EXPORT void VpSinCos(Real *psin,Real *pcos,Real *x);
-VP_EXPORT int VPrint(FILE *fp,char *cntl_chr,Real *a);
 
 /*  
  *  ------------------
@@ -177,9 +188,11 @@ VP_EXPORT int VPrint(FILE *fp,char *cntl_chr,Real *a);
 #define VpSetPosInf(a)  ((a)->frac[0]=0,(a)->Prec=1,(a)->sign=VP_SIGN_POSITIVE_INFINITE)
 #define VpSetNegInf(a)  ((a)->frac[0]=0,(a)->Prec=1,(a)->sign=VP_SIGN_NEGATIVE_INFINITE)
 #define VpSetInf(a,s)   ( ((s)>0)?VpSetPosInf(a):VpSetNegInf(a) )
+#define VpIsOne(a)      ((a->Prec==1)&&(a->frac[0]==1)&&(a->exponent==1))
 
 #ifdef _DEBUG
 int VpVarCheck(Real * v);
+VP_EXPORT int VPrint(FILE *fp,char *cntl_chr,Real *a);
 #endif /* _DEBUG */
 
 #if defined(__cplusplus)
diff --git a/ext/bigdecimal/bigdecimal_en.html b/ext/bigdecimal/bigdecimal_en.html
index b8e9768f8f..04dd83a429 100644
--- a/ext/bigdecimal/bigdecimal_en.html
+++ b/ext/bigdecimal/bigdecimal_en.html
@@ -2,90 +2,27 @@
 <HEAD>
 <META HTTP-EQUIV="Content-Type" CONTENT="text/html">
 <style type="text/css"><!--
-body {
-  color: #3f0f0f;
-  background: #fefeff;
-  margin-left: 2em; margin-right: 2em;
-}
-h1 {
-  color: #ffffff;
-  background-color: #3939AD;
-  border-color: #FF00FF;
-  width: 100%;
-  border-style: solid;
-  border-top-width: 0.1em;
-  border-bottom-width: 0.1em;
-  border-right: none;
-  border-left: none;
-  padding: 0.1em;
-  font-weight: bold;
-  font-size: 160%;
-  text-align: center;
-}
-h2 {
-  color: #00007f;
-  background-color: #e7e7ff;
-  border-color: #000094;
-  width: 100%;
-  border-style: solid;
-  border-left: none;
-  border-right: none;
-  border-top-width: 0.1em;
-  border-bottom-width: 0.1em;
-  padding: 0.1em;
-  font-weight: bold;
-  font-size: 110%;
-}
-h3 {
-  color: #00007f;
-  padding: 0.2em;
-  font-size: 110%;
-}
-h4, h5 {
-  color: #000000;
-  padding: 0.2em;
-  font-size: 100%;
-}
-table {
-  margin-top: 0.2em; margin-bottom: 0.2em;
-  margin-left: 2em; margin-right: 2em;
-}
-caption {
-  color: #7f0000;
-  font-weight: bold;
-}
-th {
-  background: #e7e7ff;
-  padding-left: 0.2em; padding-right: 0.2em;
-}
-td {
-  background: #f3f7ff;
-  padding-left: 0.2em; padding-right: 0.2em;
-}
-code {
-  color: #0000df;
-}
-dt {
-  margin-top: 0.2em;
-}
-li {
-  margin-top: 0.2em;
+body {  color: #3f0f0f;  background: #fefeff;  margin-left: 2em; margin-right: 2em;}
+h1 {  color: #ffffff;  background-color: #3939AD;  border-color: #FF00FF;  width: 100%;  border-style: solid;
+  border-top-width: 0.1em;  border-bottom-width: 0.1em;  border-right: none;  border-left: none;
+  padding: 0.1em;  font-weight: bold;  font-size: 160%;  text-align: center;}
+h2 {  color: #00007f;  background-color: #e7e7ff;  border-color: #000094;  width: 100%;  border-style: solid;  border-le  ft: none;  border-right: none;  border-top-width: 0.1em;  border-bottom-width: 0.1em;  padding: 0.1em;
+  font-weight: bold;  font-size: 110%;
 }
+h3 {  color: #00007f;  padding: 0.2em;  font-size: 110%;}
+h4, h5 {  color: #000000;  padding: 0.2em;  font-size: 100%;}
+table {  margin-top: 0.2em; margin-bottom: 0.2em;  margin-left: 2em; margin-right: 2em;}
+caption {  color: #7f0000;  font-weight: bold;}
+th {  background: #e7e7ff;  padding-left: 0.2em; padding-right: 0.2em;}
+td {  background: #f3f7ff;  padding-left: 0.2em; padding-right: 0.2em;}
+code {  color: #0000df;}
+dt {  margin-top: 0.2em;}
+li {  margin-top: 0.2em;}
 pre
-{
-    BACKGROUND-COLOR: #d0d0d0;
-    BORDER-BOTTOM: medium none;
-    BORDER-LEFT: medium none;
-    BORDER-RIGHT: medium none;
-    BORDER-TOP: medium none;
-    LINE-HEIGHT: 100%;
-    MARGIN: 12px 12px 12px 12px;
-    PADDING-BOTTOM: 12px;
-    PADDING-LEFT: 12px;
-    PADDING-RIGHT: 12px;
-    PADDING-TOP: 12px;
-    WHITE-SPACE: pre;
-    WIDTH: 100%
+{    BACKGROUND-COLOR: #d0d0d0;    BORDER-BOTTOM: medium none;    BORDER-LEFT: medium none;
+    BORDER-RIGHT: medium none;    BORDER-TOP: medium none;    LINE-HEIGHT: 100%;    MARGIN: 12px 12px 12px 12px;
+    PADDING-BOTTOM: 12px;    PADDING-LEFT: 12px;    PADDING-RIGHT: 12px;    PADDING-TOP: 12px;
+    WHITE-SPACE: pre;    WIDTH: 100%
 }
 --></style>
 
@@ -99,7 +36,6 @@ Using BigDecimal class, you can obtain any number of significant digits in compu
 For the details about Ruby see:<BR>
 <UL>
 <LI><A HREF="http://www.ruby-lang.org/en/">http://www.ruby-lang.org/en/</A>:Official Ruby page(English).</LI>
-<LI><A HREF="http://ruby.freak.ne.jp/">http://ruby.freak.ne.jp/</A>:Ruby informations(Japanese).</LI>
 <LI><A HREF="http://kahori.com/ruby/ring/">http://kahori.com/ruby/ring/</A>:Mutually linked pages relating to Ruby(Japanese).
 </LI>
 </UL> 
@@ -126,7 +62,7 @@ NOTE:<BR>
 <A NAME="#INTRO">
 <H2>Introduction</H2>
 Ruby already has builtin (variable length integer number) class Bignum. Using Bignum class,you can obtain
- any integer value in magnitude. But, variable length floating number class is not yet built in. 
+ any integer value in magnitude. But, variable length decimal number class is not yet built in. 
 This is why I made variable length floating class BigDecimal.
 Feel free to send any comments or bug reports to me.
 <A HREF="mailto:shigeo@tinyforest.gr.jp">shigeo@tinyforest.gr.jp</A>
@@ -155,16 +91,80 @@ not exactly but slightly excess memories will be allocated to newly created obje
 In 32 bits integer system,every 4 digits(in decimal) are computed simultaneously.
 This means the number of significant digits in BigDecimal is always a multiple of 4.
 
+<H4><U>Class methods</U></H4>
 <UL>
-<LI><B>new</B></LI><BR>
+<LI><B>new</B></LI><BLOCKQUOTE>
 "new" method creates a new BigDecimal object.<BR>
 a=BigDecimal::new(s[,n])<BR>
 where:<BR>
 s: Initial value string.<BR>
 n: Maximum number of significant digits of a. n must be a Fixnum object.
 If n is omitted or is equal to 0,then the maximum number of significant digits of a is determined from the length of s.
+</BLOCKQUOTE>
+
+<LI><B>mode</B></LI><BLOCKQUOTE>
+mode method controls BigDecimal computation.Following usage are defined.<BR>
+<P><B>[EXCEPTION control]</B><P>
+Actions when computation results NaN or Infinity can be defined as follows.
+<P>
+<BLOCKQUOTE>
+f = BigDecimal::mode(BigDecimal::EXCEPTION_NaN,flag)<BR>
+f = BigDecimal::mode(BigDecimal::EXCEPTION_INFINITY,flag)<BR>
+f = BigDecimal::mode(BigDecimal::EXCEPTION_UNDERFLOW,flag)<BR>
+f = BigDecimal::mode(BigDecimal::EXCEPTION_OVERFLOW,flag)<BR>
+f = BigDecimal::mode(BigDecimal::EXCEPTION_ZERODIVIDE,flag)<BR>
+f = BigDecimal::mode(BigDecimal::EXCEPTION_ALL,flag)<BR>
+</BLOCKQUOTE>
+EXCEPTION_NaN controls the execution when computation results to NaN.<BR>
+EXCEPTION_INFINITY controls the execution when computation results to Infinity(�}Infinity).<BR>
+EXCEPTION_UNDERFLOW controls the execution when computation underflows.<BR>
+EXCEPTION_OVERFLOW controls the execution when computation overflows.<BR>
+EXCEPTION_ZERODIVIDE controls the execution when zero-division occures.<BR>
+EXCEPTION_ALL controls the execution for any exception defined occures.<BR>
+If the flag is true,then the relating exception is thrown.<BR>
+No exception is thrown when the flag is false(default) and computation 
+continues with the result:<BR>
+<BLOCKQUOTE>
+EXCEPTION_NaN results to NaN<BR>
+EXCEPTION_INFINITY results to +Infinity or -Infinity<BR>
+EXCEPTION_UNDERFLOW results to 0.<BR>
+EXCEPTION_OVERFLOW results to +Infinity or -Infinity<BR>
+EXCEPTION_ZERODIVIDE results to +Infinity or -Infinity<BR>
+</BLOCKQUOTE>
+EXCEPTION_INFINITY,EXCEPTION_OVERFLOW, and EXCEPTION_ZERODIVIDE are
+ currently the same.<BR>
+The return value of mode method is the previous value set.<BR>
+nil is returned if any argument is wrong.<BR>
+Suppose the return value of the mode method is f,then 
+ f &amp; BigDecimal::EXCEPTION_NaN !=0 means EXCEPTION_NaN is set to on.
+<P>
+<B>[ROUND error control]</B><P>
+Rounding operation can be controlled as:
+<BLOCKQUOTE>
+f = BigDecimal::mode(BigDecimal::COMP_MODE,flag)
+</BLOCKQUOTE>
+where flag must be one of:
+<TABLE>
+<TR><TD>COMP_MODE_TRUNCATE</TD><TD>truncate</TD></TR>
+<TR><TD>COMP_MODE_ROUNDUP</TD><TD>roundup,default</TD></TR>
+<TR><TD>COMP_MODE_CEIL</TD><TD>ceil</TD></TR>
+<TR><TD>COMP_MODE_FLOOR</TD><TD>floor</TD></TR>
+<TR><TD>COMP_MODE_EVEN</TD><TD>Banker's rounding</TD></TR>
+</TABLE>
+nil is returned if any argument is illegal.<BR>
+The digit location for rounding operation can not be specified by mode method,
+use truncate/roundup/ceil/floor mthods for each instance instead.
+
+</BLOCKQUOTE>
 
-<LI><B>double_fig</B></LI><BR>
+<LI><B>limit[(n)]</B></LI><BLOCKQUOTE>
+Limits the maximum digits that the newly created BigDecimal objects can hold
+never exceed n. Returns maximum value before set.
+Zero,the default value,means no upper limit.<BR>
+mf = BigDecimal::limit(n)<BR>
+</BLOCKQUOTE>
+
+<LI><B>double_fig</B></LI><BLOCKQUOTE>
 double_fig is a class method which returns the number of digits 
 the Float class can have.
 <CODE><PRE>
@@ -180,71 +180,71 @@ double_fig is:
     v /= 10;
  }
 </PRE></CODE>
+</BLOCKQUOTE>
 
-<LI><B>prec</B></LI><BR>
-r,m = a.prec<BR>
-where r is the number of significant digits of a,
-m is the maximum number of significant digits a can hold.<br>
-<CODE><PRE>
-  require "bigdecimal"
-  a = BigDecimal.new("0.12345")
-  p a.prec                              # ==> [8, 12]
-  b = BigDecimal.new("0.1234500000000")
-  p b.prec                              # ==> [8, 20]
-  c = BigDecimal.new("0.12345",20)
-  p c.prec                              # ==> [8, 24]
-</PRE></CODE>
-r and m are always the multiple of log10(BigDecimal::BASE).
+<LI><B>BASE</B></LI><BLOCKQUOTE>
+Base value used in the BigDecimal calculation.
+On 32 bits integer system,the value of BASE is 10000.<BR>
+b = BigDecimal::BASE<BR>
+</BLOCKQUOTE>
+
+<LI><B>E</B></LI><BLOCKQUOTE>
+e = BigDecimal::E(n)<BR>
+where e(=2.718281828....) is the base value of natural logarithm.<BR>
+n specifies the length of significant digits of e.
+
+</BLOCKQUOTE>
+<LI><B>PI</B></LI><BLOCKQUOTE>
+e = BigDecimal::PI(n)<BR>
+returns at least n digits of the ratio of the circumference of a circle to its diameter
+(pi=3.14159265358979....) using J.Machin's formula.<BR>
+</BLOCKQUOTE>
+</UL>
 
-<LI><B>+</B></LI><BR>
+<H4><U>Instance methods</U></H4>
+<UL>
+<LI><B>+</B></LI><BLOCKQUOTE>
 addition(c = a + b)<BR>
 For the resulting number of significant digits of c,see <A HREF="#PREC">Resulting number of significant digits</A>.
 
-<LI><B>-</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>-</B></LI><BLOCKQUOTE>
 subtraction (c = a - b) or negation (c = -a)<BR>
 For the resulting number of significant digits of c,see <A HREF="#PREC">Resulting number of significant digits</A>.
 
-<LI><B>*</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>*</B></LI><BLOCKQUOTE>
 multiplication(c = a * b)<BR>
 For the resulting number of significant digits of c,see <A HREF="#PREC">Resulting number of significant digits</A>.
 
-<LI><B>/</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>/</B></LI><BLOCKQUOTE>
 division(c = a / b)<BR>
 For the resulting number of significant digits of c,see <A HREF="#PREC">Resulting number of significant digits</A>.
+</BLOCKQUOTE>
 
-<LI><B>assign</B></LI><BR>
-c = a.assign(n,f)<BR>
-assigns the value of a to c.<BR>
-n is the number of significant digits of resulting c.<BR>
-If f > 0,then a is assigned to c.<BR>
-If f < 0,then -a is assigned to c.<BR>
-The absolute value of f (|f|) must be 1 or 2.
-If |f|=2,then proper round operation over c is performed,when the maximum 
-number of significant digits of c is less than current 
-number of significant digits of a.
-If |f|=1 then extra digits are discarded when the maximum 
-number of significant digits of c is less than current 
-number of significant digits of a.
-
-<LI><B>add</B></LI><BR>
+<LI><B>add</B></LI><BLOCKQUOTE>
 c = a.add(b,n)<BR>
 c = a.add(b,n) performs c = a + b.
 If n is less than the actual significant digits of a + b,
 then c is rounded properly.
 
-<LI><B>sub</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>sub</B></LI><BLOCKQUOTE>
 c = a.sub(b,n)<BR>
 c = a.sub(b,n) performs c = a - b.
 If n is less than the actual significant digits of a - b,
 then c is rounded properly.
 
-<LI><B>mult</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>mult</B></LI><BLOCKQUOTE>
 c = a.mult(b,n)<BR>
 c = a.mult(b,n) performs c = a * b.
 If n is less than the actual significant digits of a * b,
 then c is rounded properly.
 
-<LI><B>div</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>div</B></LI><BLOCKQUOTE>
 c,r = a.div(b,n)<BR>
 c,r = a.div(b,n) performs c = a / b, r is the residue of a / b.
 If necessary,the divide operation continues to n digits which c
@@ -253,169 +253,154 @@ Unlike the divmod method,c is not always an integer.
 c is never rounded,and the equation a = c*b + r is always 
 valid unless c is NaN or Infinity.
 
-<LI><B>%</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>%</B></LI><BLOCKQUOTE>
 r = a%b <BR>
 is the same as:<BR>
 r = a-((a/b).floor)*b<BR>
 
-<LI><B>fix</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>fix</B></LI><BLOCKQUOTE>
 c = a.fix<BR>
 returns integer part of a.<BR>
 
-<LI><B>frac</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>frac</B></LI><BLOCKQUOTE>
 c = a.frac<BR>
 returns fraction part of a.<BR>
 
-<LI><B>floor[(n)]</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>floor[(n)]</B></LI><BLOCKQUOTE>
 c = a.floor<BR>
-returns the maximum integer value (in BigDecimal) which is less than or equal to a.<BR>
-As shown in the following example,an optional integer argument (n) specifying the position 
-of 'floor'ed digit can be given.
-If n> 0,then the (n+1)th digit counted from the decimal point in fraction part is 'floor'ed.
-If n<0,then the n-th digit counted from the decimal point in integer part is 'floor'ed.<BR>
+returns the maximum integer value (in BigDecimal) which is less than or equal to a.
+<PRE><CODE>
+ c = BigDecimal("1.23456").floor  #  ==> 1
+ c = BigDecimal("-1.23456").floor #  ==> -2
+</CODE></PRE>
 
-c = BigDecimal::new("1.23456")<BR>
-d = c.floor(4) # d = 1.2345<BR>
-c = BigDecimal::new("15.23456")<BR>
-d = c.floor(-1) # d = 10.0<BR>
+As shown in the following example,an optional integer argument (n) specifying the position 
+of the target digit can be given.<BR>
+If n> 0,then the (n+1)th digit counted from the decimal point in fraction part is processed(resulting number of fraction part digits is less than or equal to n).<BR>
+If n<0,then the n-th digit counted from the decimal point in integer part is processed(at least n 0's are placed from the decimal point to left).
+<PRE><CODE>
+ c = BigDecimal::new("1.23456").floor(4)   #  ==> 1.2345
+ c = BigDecimal::new("15.23456").floor(-1) #  ==> 10.0
+</CODE></PRE>
 
-<LI><B>ceil[(n)]</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>ceil[(n)]</B></LI><BLOCKQUOTE>
 c = a.ceil<BR>
-returns the minimum integer value (in BigDecimal) which is greater than or equal to a.<BR>
-As shown in the following example,an optional integer argument (n) specifying the position 
-of 'ceil'ed digit can be given.
-If n>0,then the (n+1)th digit counted from the decimal point in fraction part is 'ceil'ed.
-If n<0,then the n-th digit counted from the decimal point in integer part is 'ceil'ed.<BR>
+returns the minimum integer value (in BigDecimal) which is greater than or equal to a.
+<PRE><CODE>
+ c = BigDecimal("1.23456").ceil  #  ==> 2
+ c = BigDecimal("-1.23456").ceil #  ==> -1
+</CODE></PRE>
 
-c = BigDecimal::new("1.23456")<BR>
-d = c.ceil(4) # d = 1.2346<BR>
-c = BigDecimal::new("15.23456")<BR>
-d = c.ceil(-1) # d = 20.0<BR>
+As shown in the following example,an optional integer argument (n) specifying the position 
+of the target digit can be given.<BR>
+If n>0,then the (n+1)th digit counted from the decimal point in fraction part is processed(resulting number of fraction part digits is less than or equal to n).<BR>
+If n<0,then the n-th digit counted from the decimal point in integer part is processed(at least n 0's are placed from the decimal point to left).
+<PRE><CODE>
+ c = BigDecimal::new("1.23456").ceil(4)   # ==> 1.2346
+ c = BigDecimal::new("15.23456").ceil(-1) # ==> 20.0
+</CODE></PRE>
 
-<LI><B>round[(n)]</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>round[(n[,b])]</B></LI><BLOCKQUOTE>
 c = a.round<BR>
-round off a to the nearest 1�D<BR>
+round a to the nearest 1�D<BR>
+<PRE><CODE>
+ c = BigDecimal("1.23456").round  #  ==> 1
+ c = BigDecimal("-1.23456").round #  ==> -1
+</CODE></PRE>
+
 As shown in the following example,an optional integer argument (n) specifying the position 
-of rounded digit can be given.
-If n>0,then the (n+1)th digit counted from the decimal point in fraction part is rounded.
-If n<0,then the n-th digit counted from the decimal point in integer part is rounded.<BR>
+of the target digit can be given.<BR>
+If n>0,then the (n+1)th digit counted from the decimal point in fraction part is processed(resulting number of fraction part digits is less than or equal to n).<BR>
+If n<0,then the n-th digit counted from the decimal point in integer part is processed(at least n 0's are placed from the decimal point to left).
+<PRE><CODE>
+c = BigDecimal::new("1.23456").round(4)   #  ==> 1.2346
+c = BigDecimal::new("15.23456").round(-1) #  ==> 20.0
+</CODE></PRE>
 
-c = BigDecimal::new("1.23456")<BR>
-d = c.round(4)  # d = 1.235 <BR>
-c = BigDecimal::new("15.23456")<BR>
-d = c.round(-1) # d = 20.0<BR>
+If the second optional argument b is given with the non-zero value(default is zero) then 
+so called Banker's rounding is performed.<BR>
+Suppose the digit p is to be rounded,then:<BR>
+ If p<5 then p is truncated<BR>
+ If p>5 then p is rounded up<BR>
+ If p is 5 then round up operation is taken only when the left hand side digit of p is odd.
+<PRE><CODE>
+c = BigDecimal::new("1.23456").round(3,1)   #  ==> 1.234
+c = BigDecimal::new("1.23356").round(3,1)   #  ==> 1.234
+</CODE></PRE>
 
-<LI><B>truncate[(n)]</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>truncate[(n)]</B></LI><BLOCKQUOTE>
 c = a.truncate<BR>
 truncate a to the nearest 1�D<BR>
 As shown in the following example,an optional integer argument (n) specifying the position 
-of truncated digit can be given.
-If n>0,then the (n+1)th digit counted from the decimal point in fraction part is truncated.
-If n<0,then the n-th digit counted from the decimal point in integer part is truncated.<BR>
+of the target digit can be given.<BR>
+If n>0,then the (n+1)th digit counted from the decimal point in fraction part is processed(resulting number of fraction part digits is less than or equal to n).<BR>
+If n<0,then the n-th digit counted from the decimal point in integer part is processed(at least n 0's are placed from the decimal point to left).
 
-c = BigDecimal::new("1.23456")<BR>
-d = c.truncate(4)  # d = 1.2345<BR>
-c = BigDecimal::new("15.23456")<BR>
-d = c.truncate(-1) # d = 10.0<BR>
+<PRE><CODE>
+c = BigDecimal::new("1.23456").truncate(4)   #  ==> 1.2345
+c = BigDecimal::new("15.23456").truncate(-1) #  ==> 10.0
+</CODE></PRE>
 
-<LI><B>divmod</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>divmod</B></LI><BLOCKQUOTE>
 c,r = a.divmod(b) # a = c*b + r<BR>
 returns the quotient and remainder of a/b.<BR>
 a = c * b + r is always satisfied.<BR>
-where c is the integer sutisfying
+where c is the integer satisfying
 c = (a/b).floor <BR>
 and,therefore 
 r = a - c*b<BR>
 
-<LI><B>remainder</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>remainder</B></LI><BLOCKQUOTE>
 r=a.remainder(b)<BR>
 returns the remainder of a/b.<BR>
-where c is the integer sutisfying 
+where c is the integer satisfying 
 c = (a/b).fix <BR>
 and,therefore: 
 r = a - c*b<BR>
 
-<LI><B>abs</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>abs</B></LI><BLOCKQUOTE>
 c = a.abs<BR>
 returns an absolute value of a.<BR>
 
-<LI><B>to_i</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>to_i</B></LI><BLOCKQUOTE>
 changes a to an integer.<BR>
 i = a.to_i<BR>
 i becomes to Fixnum or Bignum.
-IF a is Infinity or NaN,then i becomes to nil.
+If a is Infinity or NaN,then i becomes to nil.
 
-<LI><B>to_s[(n)]</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>to_s[(n)]</B></LI><BLOCKQUOTE>
 converts to string(results look like "0.xxxxxEn").<BR>
 s = a.to_s<BR>
 If n is given,then a space is inserted after every n digits for readability.<BR>
 s = a.to_s(n)
 
-<LI><B>exponent</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>exponent</B></LI><BLOCKQUOTE>
 returns an integer holding exponent value of a.<BR>
 n = a.exponent <BR>
 means a = 0.xxxxxxx*10**n.
 
-<LI><B>to_f</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>to_f</B></LI><BLOCKQUOTE>
 same as dup method.
 creates a new BigDecimal object having same value.
+</BLOCKQUOTE>
 
-<LI><B>E</B></LI><BR>
-e = BigDecimal::E(n)<BR>
-where e(=2.718281828....) is the base value of natural logarithm.<BR>
-n specifies the length of significant digits of e.
-
-<LI><B>PI</B></LI><BR>
-e = BigDecimal::PI(n)<BR>
-returns at least n digits of the ratio of the circumference of a circle to its dirmeter
-(pi=3.14159265358979....) using J.Machin's formula.<BR>
-
-<LI><B>BASE</B></LI><BR>
-Base value used in the BigDecimal calculation.
-On 32 bit integer system,the value of BASE is 10000.<BR>
-b = BigDecimal::BASE<BR>
-
-<LI><B>mode</B></LI><BR>
-mode method controls BigDecimal computation.
-Following usage are defined.<BR>
-
-f = BigDecimal::mode(BigDecimal::EXCEPTION_NaN,flag)<BR>
-f = BigDecimal::mode(BigDecimal::EXCEPTION_INFINITY,flag)<BR>
-f = BigDecimal::mode(BigDecimal::EXCEPTION_UNDERFLOW,flag)<BR>
-f = BigDecimal::mode(BigDecimal::EXCEPTION_OVERFLOW,flag)<BR>
-f = BigDecimal::mode(BigDecimal::EXCEPTION_ZERODIVIDE,flag)<BR>
-f = BigDecimal::mode(BigDecimal::EXCEPTION_ALL,flag)<BR>
-
-EXCEPTION_NaN controls the execution once computation results to NaN.
-EXCEPTION_INFINITY controls the execution once computation results to Infinity(�}Infinity).
-EXCEPTION_UNDERFLOW controls the execution once computation underflows.
-EXCEPTION_OVERFLOW controls the execution once computation overflows.
-EXCEPTION_ZERODIVIDE controls the execution once zero-division occures.
-EXCEPTION_ALL controls the execution for any exception defined occures.
-If the flag is true,then the relating exception is thrown.
-No exception is thrown when the flag is false(default) and computation 
-continues with the result:<BR>
-EXCEPTION_NaN results to NaN<BR>
-EXCEPTION_INFINITY results to +Infinity or -Infinity<BR>
-EXCEPTION_UNDERFLOW results to 0.<BR>
-EXCEPTION_OVERFLOW results to +Infinity or -Infinity<BR>
-EXCEPTION_ZERODIVIDE results to +Infinity or -Infinity<BR>
-EXCEPTION_INFINITY,EXCEPTION_OVERFLOW, and EXCEPTION_ZERODIVIDE are
- currently the same.<BR>
-The return value of mode method is the value set.
-Suppose the return value of the mode method is f,then 
- f & BigDecimal::EXCEPTION_NaN !=0 means EXCEPTION_NaN is set to on.
-If the value of the argument flag is other than nil,true nor false then 
-current mode status is returned.
-
-<LI><B>limit[(n)]</B></LI><BR>
-Limits the maximum digits that the newly created BigDecimal objects can hold
-never exceed n. Returns maximum value before set.
-Zero,the default value,means no upper limit.<BR>
-mf = BigDecimal::limit(n)<BR>
-
-<LI><B>sign</B></LI><BR>
-returns the 'attribute'.
+</BLOCKQUOTE>
+<LI><B>sign</B></LI><BLOCKQUOTE>
+returns the 'attribute' of a.
 n = a.sign <BR>
 where the value of n means that a is:<BR>
 n = BigDecimal::SIGN_NaN(0) : a is NaN<BR>
@@ -427,28 +412,42 @@ n = BigDecimal::SIGN_POSITIVE_INFINITE(3) : a is +Infinity<BR>
 n = BigDecimal::SIGN_NEGATIVE_INFINITE(-3) : a is -Infinity<BR>
 The value in () is the actual value,see (<A HREF="#STRUCT">Internal structure</A>.<BR>
 
-<LI><B>nan?</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>nan?</B></LI><BLOCKQUOTE>
 a.nan? returns True when a is NaN.
 
-<LI><B>infinite?</B></LI><BR>
-a.infinite? returns True when a is +�� or -��.
+</BLOCKQUOTE>
+<LI><B>infinite?</B></LI><BLOCKQUOTE>
+a.infinite? returns 1 when a is +��,-1 when a is -��, nil otherwise.
+
+</BLOCKQUOTE>
+<LI><B>finite?</B></LI><BLOCKQUOTE>
+a.finite? returns true when a is neither �� nor NaN.
+</BLOCKQUOTE>
 
-<LI><B>finite?</B></LI><BR>
-a.finite? returns True when a is neither �� nor NaN.
+<LI><B>zero?</B></LI><BLOCKQUOTE>
+c = a.zero?<BR>
+returns true if a is equal to 0,otherwise returns false<BR>
+</BLOCKQUOTE>
+<LI><B>nonzero?</B></LI><BLOCKQUOTE>
+c = a.nonzero?<BR>
+returns nil if a is 0,otherwise returns a itself.<BR>
+</BLOCKQUOTE>
 
-<LI><B>to_parts</B></LI><BR>
+<LI><B>split</B></LI><BLOCKQUOTE>
 decomposes a BigDecimal value to 4 parts.
 All 4 parts are returned as an array.<BR>
 Parts consist of a sign(0 when the value is NaN,+1 for positive and
  -1 for negative value), a string representing fraction part,base value(always 10 currently),and an integer(Fixnum) for exponent respectively.
-a=BigDecimal::new("3.14159265",10)<BR>
-f,x,y,z = a.to_parts<BR>
+a=BigDecimal::new("3.14159265")<BR>
+f,x,y,z = a.split<BR>
 where f=+1,x="314159265",y=10 and z=1<BR>
 therefore,you can translate BigDecimal value to Float as:<BR>
 s = "0."+x<BR>
 b = f*(s.to_f)*(y**z)<BR>
 
-<LI><B>inspect</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>inspect</B></LI><BLOCKQUOTE>
 is used for debugging output.<BR>
 p a=BigDecimal::new("3.14",10)<BR>
 should produce output like "#&lt;0x112344:'0.314E1',4(12)%gt;".
@@ -457,38 +456,44 @@ where "0x112344" is the address,
 and 12 is the maximum number of the significant digits 
 the object can hold.
 
-<LI><B>dup</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>dup</B></LI><BLOCKQUOTE>
 creates a new BigDecimal object having same value.
 
-<LI><B>sqrt</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>sqrt</B></LI><BLOCKQUOTE>
 c = a.sqrt(n)<BR>
 computes square root value of a with significant digit number n at least.<BR>
 
-<LI><B>sincos</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>sincos</B></LI><BLOCKQUOTE>
 computes and returns sine and cosine value of a with significant digit number n at least.<BR>
 sin,cos = a.sincos(n)<BR>
 Computation may return bad results unless |a|<2*3.1415..... 
-<LI><B>exp</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>exp</B></LI><BLOCKQUOTE>
 c = a.exp(n)<BR>
 computes the base of natural logarithm value(e=2.718281828....) powered by a
 with significant digit number n at least.<BR>
 
-<LI><B>power</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>**</B></LI><BLOCKQUOTE>
+c = a ** n<BR>
+returns the value of a powered by n.
+n must be an integer.<BR>
+
+</BLOCKQUOTE>
+<LI><B>power</B></LI><BLOCKQUOTE>
+The same as ** method.<BR>
 c = a.power(n)<BR>
 returns the value of a powered by n(c=a**n).
 n must be an integer.<BR>
 
-<LI><B>zero?</B></LI><BR>
-c = a.zero?<BR>
-returns true if a is equal to 0,otherwise returns false<BR>
-
-<LI><B>nonzero?</B></LI><BR>
-c = a.nonzero?<BR>
-returns false if a is 0,otherwise returns a itself.<BR>
-
-<LI><B>&lt;=&gt;</B></LI><BR>
+</BLOCKQUOTE>
+<LI><B>&lt;=&gt;</B></LI><BLOCKQUOTE>
 c = a &lt;=&gt; b <BR>
 returns 0 if a==b,1 if a &gt b,and returns -1 if a &lt b.<BR>
+</BLOCKQUOTE>
 </UL>
 
 Following methods need no explanation.<BR>
diff --git a/ext/bigdecimal/bigdecimal_ja.html b/ext/bigdecimal/bigdecimal_ja.html
index efd4228d9a..56bebaa863 100644
--- a/ext/bigdecimal/bigdecimal_ja.html
+++ b/ext/bigdecimal/bigdecimal_ja.html
@@ -2,90 +2,30 @@
 <HEAD>
 <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=Shift_JIS">
 <style type="text/css"><!--
-body {
-  color: #3f0f0f;
-  background: #fefeff;
-  margin-left: 2em; margin-right: 2em;
+body { color: #3f0f0f;  background: #fefeff; margin-left: 2em; margin-right: 2em;}
+h1 { color: #ffffff;  background-color: #3939AD;  border-color: #FF00FF;  width: 100%;
+  border-style: solid;  border-top-width: 0.1em;  border-bottom-width: 0.1em;  border-right: none;
+  border-left: none;  padding: 0.1em;  font-weight: bold;  font-size: 160%;  text-align: center;
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-h1 {
-  color: #ffffff;
-  background-color: #3939AD;
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-  border-style: solid;
-  border-top-width: 0.1em;
-  border-bottom-width: 0.1em;
-  border-right: none;
-  border-left: none;
+h2 {  color: #00007f;  background-color: #e7e7ff;  border-color: #000094;  width: 100%;
+  border-style: solid; border-left: none;  border-right: none;  border-top-width: 0.1em;  border-bottom-width: 0.1em;
   padding: 0.1em;
-  font-weight: bold;
-  font-size: 160%;
-  text-align: center;
-}
-h2 {
-  color: #00007f;
-  background-color: #e7e7ff;
-  border-color: #000094;
-  width: 100%;
-  border-style: solid;
-  border-left: none;
-  border-right: none;
-  border-top-width: 0.1em;
-  border-bottom-width: 0.1em;
-  padding: 0.1em;
-  font-weight: bold;
-  font-size: 110%;
-}
-h3 {
-  color: #00007f;
-  padding: 0.2em;
-  font-size: 110%;
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-h4, h5 {
-  color: #000000;
-  padding: 0.2em;
-  font-size: 100%;
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-table {
-  margin-top: 0.2em; margin-bottom: 0.2em;
-  margin-left: 2em; margin-right: 2em;
-}
-caption {
-  color: #7f0000;
-  font-weight: bold;
-}
-th {
-  background: #e7e7ff;
-  padding-left: 0.2em; padding-right: 0.2em;
-}
-td {
-  background: #f3f7ff;
-  padding-left: 0.2em; padding-right: 0.2em;
-}
-code {
-  color: #0000df;
-}
-dt {
-  margin-top: 0.2em;
-}
-li {
-  margin-top: 0.2em;
+  font-weight: bold;  font-size: 110%;
 }
+h3 {  color: #00007f;  padding: 0.2em;  font-size: 110%;}
+h4, h5 {  color: #000000;  padding: 0.2em;  font-size: 100%;}
+table {  margin-top: 0.2em; margin-bottom: 0.2em;  margin-left: 2em; margin-right: 2em;}
+caption {  color: #7f0000;  font-weight: bold;}
+th {  background: #e7e7ff;  padding-left: 0.2em; padding-right: 0.2em;}
+td {  background: #f3f7ff;  padding-left: 0.2em; padding-right: 0.2em;}
+code {  color: #0000df;}
+dt {  margin-top: 0.2em;}
+li {  margin-top: 0.2em;}
 pre
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-    PADDING-LEFT: 12px;
-    PADDING-RIGHT: 12px;
-    PADDING-TOP: 12px;
-    WHITE-SPACE: pre;
-    WIDTH: 100%
+{    BACKGROUND-COLOR: #d0d0d0;    BORDER-BOTTOM: medium none;    BORDER-LEFT: medium none;
+    BORDER-RIGHT: medium none;    BORDER-TOP: medium none;    LINE-HEIGHT: 100%;    MARGIN: 12px 12px 12px 12px;
+    PADDING-BOTTOM: 12px;    PADDING-LEFT: 12px;    PADDING-RIGHT: 12px;    PADDING-TOP: 12px;
+    WHITE-SPACE: pre;    WIDTH: 100%
 }
 --></style>
 
@@ -99,7 +39,6 @@ BigDecimal �̓I�u�W�F�N�g�w���̋��͂ȃX�N���v�g����ł��� Ruby �ɉϒ����������
 Ruby �ɂ��Ă̏ڂ������e�͈ȉ���URL���Q�Ƃ��Ă��������B
 <UL>
 <LI><A HREF="http://www.ruby-lang.org/ja/">http://www.ruby-lang.org/ja/</A>�FRuby�����y�[�W</LI>
-<LI><A HREF="http://ruby.freak.ne.jp/">http://ruby.freak.ne.jp/</A>�FRuby�Ɋւ�����y�[�W</LI>
 <LI><A HREF="http://kahori.com/ruby/ring/">http://kahori.com/ruby/ring/</A>�FRuby�Ɋւ���y�[�W��H��܂�</LI>
 </UL> 
 <hr>
@@ -160,8 +99,9 @@ c=a+b
 �Ⴆ�΂R�Q�r�b�g�̃V�X�e���ł͂P�O�i�łS�����Ɍv�Z���܂��B�]���āA����ł́A
 �����́u�L�������v�͂S�̔{���ƂȂ��Ă��܂��B
 
+<H4><U>�N���X���\�b�h</U></H4>
 <UL>
-<LI>new</LI><BR>
+<LI><B>new</B></LI><BLOCKQUOTE>
 �V���� BigDecimal �I�u�W�F�N�g�𐶐����܂��B<BR>
 a=BigDecimal::new(s[,n])<BR>
 s �͏����l�𕶎���Ŏw�肵�܂��D
@@ -169,50 +109,151 @@ n �͕K�v�ȗL�������ia �̍ő�L�������j�𐮐��Ŏw�肵�܂��B
 n �� 0 �܂��͏ȗ����ꂽ�Ƃ��́An �̒l�� s �̗L�������Ƃ݂Ȃ���܂��B
 s �̗L��������� n ���������Ƃ��� n=0 �̂Ƃ��Ɠ����ł��B
 a �̍ő�L�������� n ���኱�傢�l���̗p����܂��B
-<LI>+</LI><BR>
+</BLOCKQUOTE>
+
+<LI><B>mode</B></LI><BLOCKQUOTE>
+BigDecimal�̎��s���ʂ𐧌䂵�܂��B�ȉ��̎g�p���@����`����Ă��܂��B
+<P>
+<B>[��O����]</B><P>
+�v�Z���ʂ���(NaN)��[���ɂ�鏜�Z�ɂȂ����Ƃ��̏������`���邱�Ƃ��ł��܂��B
+<BLOCKQUOTE>
+f = BigDecimal::mode(BigDecimal::EXCEPTION_NaN,flag)<BR>
+f = BigDecimal::mode(BigDecimal::EXCEPTION_INFINITY,flag)<BR>
+f = BigDecimal::mode(BigDecimal::EXCEPTION_UNDERFLOW,flag)<BR>
+f = BigDecimal::mode(BigDecimal::EXCEPTION_OVERFLOW,flag)<BR>
+f = BigDecimal::mode(BigDecimal::EXCEPTION_ZERODIVIDE,flag)<BR>
+f = BigDecimal::mode(BigDecimal::EXCEPTION_ALL,flag)<BR>
+</BLOCKQUOTE>
+
+EXCEPTION_NaN �͌��ʂ� NaN �ɂȂ����Ƃ��̎w��ł��B<BR>
+EXCEPTION_INFINITY �͌��ʂ�������(�}Infinity)�ɂȂ����Ƃ��̎w��ł��B<BR>
+EXCEPTION_UNDERFLOW �͎w�������A���_�[�t���[����Ƃ��̎w��ł��B<BR>
+EXCEPTION_OVERFLOW �͎w�������I�[�o�[�t���[����Ƃ��̎w��ł��B<BR>
+EXCEPTION_ZERODIVIDE �̓[���ɂ�銄��Z�����s�����Ƃ��̎w��ł��B<BR>
+EXCEPTION_ALL �́A�\�ȑS�Ăɑ΂��Ĉꊇ���Đݒ肷��Ƃ��Ɏg�p���܂��B<BR><BR>
+
+flag �� true �̂Ƃ��́A�w�肵����ԂɂȂ����Ƃ��ɗ�O�𔭍s����悤�ɂȂ�܂��B<BR>
+flag �� false�i�f�t�H���g�j�Ȃ�A��O�͔��s����܂���B�v�Z���ʂ͈ȉ��̂悤�ɂȂ�܂��B<BR>
+<BLOCKQUOTE>
+EXCEPTION_NaN �̂Ƃ��A��(NaN)<BR>
+EXCEPTION_INFINITY �̂Ƃ��A����(+ or -Infinity)<BR>
+EXCEPTION_UNDERFLOW �̂Ƃ��A�[��<BR>
+EXCEPTION_OVERFLOW �̂Ƃ��A+Infinity �� -Infinity<BR>
+EXCEPTION_ZERODIVIDE �̂Ƃ��A+Infinity �� -Infinity<BR>
+</BLOCKQUOTE>
+EXCEPTION_INFINITY�AEXCEPTION_OVERFLOW�AEXCEPTION_ZERODIVIDE
+�͍��̂Ƃ��듯���ł��B<BR>
+�߂�l�́A�ݒ�O�̒l�ł��B�u�l�v�̈Ӗ��́A�Ⴆ��
+BigDecimal::EXCEPTION_NaN�Ɓu�l�v�� & �� �[���ȊO�Ȃ��
+EXCEPTION_NaN���ݒ肳��Ă���Ƃ����Ӗ��ł��B<BR>
+�����ɐ������Ȃ����̂��w�肳�ꂽ�ꍇ�� nil ���Ԃ�܂��B
+
+<P>
+<B>[�ۂߏ����w��]</B><P>
+�v�Z�r���̊ۂߑ���̎w�肪�ł��܂��B
+<BLOCKQUOTE>
+f = BigDecimal::mode(BigDecimal::COMP_MODE,flag)
+</BLOCKQUOTE>
+�̌`���Ŏw�肵�܂��B<BR>
+�����ŁAflag �͈ȉ��̈���w�肵�܂��B
+<TABLE>
+<TR><TD>COMP_MODE_TRUNCATE</TD><TD>�S�Đ؂�̂Ă܂�(truncate)�B</TD></TR>
+<TR><TD>COMP_MODE_ROUNDUP</TD><TD>�l�̌ܓ����܂�(roundup�A�f�t�H���g)�B</TD></TR>
+<TR><TD>COMP_MODE_CEIL</TD><TD>���l�̑傫�����ɌJ��グ�܂�(ceil)�B</TD></TR>
+<TR><TD>COMP_MODE_FLOOR</TD><TD>���l�̏��������ɌJ�艺���܂�(floor)�B</TD></TR>
+<TR><TD>COMP_MODE_EVEN</TD><TD>�l�̘Z�����܂��B�T�̎��͏�ʂP������̎��̂݌J��グ�܂�(Banker's rounding)�B</TD></TR>
+</TABLE>
+�߂�l�͎w��O�� flag �̒l�ł��B
+�����ɐ������Ȃ����̂��w�肳�ꂽ�ꍇ�� nil ���Ԃ�܂��B<BR>
+mode ���\�b�h�ł͊ۂߑ���̈ʒu�����[�U���w�肷�邱�Ƃ͂ł��܂���B
+�ۂߑ���ƈʒu�������Ő��䂵�����ꍇ�� truncate/roundup/ceil/floor �Ƃ�����
+�C���X�^���X���\�b�h���g�p���ĉ������B
+</BLOCKQUOTE>
+<LI><B>limit([n])</B></LI><BLOCKQUOTE>
+���������BigDecimal�I�u�W�F�N�g�̍ő包����n���ɐ������܂��B�߂�l��
+�ݒ肷��O�̒l�ł��B�ݒ�l�̃f�t�H���g�l�͂O�ŁA�����������Ƃ����Ӗ��ł��B
+n���w�肵�Ȃ��ꍇ�́A����̍ő包�����Ԃ�܂��B<BR>
+mf = BigDecimal::limit(n)<BR>
+</BLOCKQUOTE>
+<LI><B>double_fig</B></LI><BLOCKQUOTE>
+Ruby �� Float �N���X���ێ��ł���L�������̐���Ԃ��܂��B
+<CODE><PRE>
+  p BigDecimal::double_fig  # ==> 20 (depends on the CPU etc.)
+</PRE></CODE>
+double_fig�͈ȉ��� C �v���O�����̌��ʂƓ����ł��B
+<CODE><PRE>
+ double v          = 1.0;
+ int    double_fig = 0;
+ while(v + 1.0 > 1.0) {
+    ++double_fig;
+    v /= 10;
+ }
+</PRE></CODE>
+</BLOCKQUOTE>
+
+<LI><B>BASE</B></LI><BLOCKQUOTE>
+�����Ŏg�p������̒l�ł��B������ 32 �r�b�g�̏����n�ł�10000�ł��B<BR>
+b = BigDecimal::BASE<BR>
+</BLOCKQUOTE>
+
+<LI><B>E</B></LI><BLOCKQUOTE>
+���R�ΐ��̒�e(=2.718281828....)���v�Z���܂��i�����Ƀe�C���[�W�J�Łj�B<BR>
+e = BigDecimal::E(n)<BR>
+n�͕K�v�ȗL�������𐮐��Ŏw�肵�܂��B
+</BLOCKQUOTE>
+<LI><B>PI</B></LI><BLOCKQUOTE>
+�~����(=3.14159265358979....)���v�Z���܂��iJ�DMachin�̌�����p���܂��j�B<BR>
+e = BigDecimal::PI(n)<BR>
+n �͕K�v�ȗL�������𐮐��Ŏw�肵�܂��B
+</BLOCKQUOTE>
+</UL>
+
+<H4><U>�C���X�^���X���\�b�h</U></H4>
+<UL>
+<LI><B>+</B></LI><BLOCKQUOTE>
 ���Z�ic = a + b�j<BR>
 c �̐��x�ɂ��Ắu<A HREF="#PREC">�v�Z���x�ɂ���</A>�v���Q�Ƃ��Ă��������B
-<LI>-</LI><BR>
+</BLOCKQUOTE>
+
+<LI><B>-</B></LI><BLOCKQUOTE>
 ���Z�ic = a - b�j�A�܂��͕������]�ic = -a�j<BR>
 c �̐��x�ɂ��Ắu<A HREF="#PREC">�v�Z���x�ɂ���</A>�v���Q�Ƃ��Ă��������B
-<LI>*</LI><BR>
+
+</BLOCKQUOTE>
+<LI><B>*</B></LI><BLOCKQUOTE>
 ��Z(c = a * b)<BR>
 c�̐��x��(a�̐��x)+(b�̐��x)���x�ł��B<br>
 �ڂ����́u<A HREF="#PREC">�v�Z���x�ɂ���</A>�v���Q�Ƃ��Ă��������B
 
-<LI>/</LI><BR>
+</BLOCKQUOTE>
+<LI><B>/</B></LI><BLOCKQUOTE>
 ���Z(c = a / b)<BR>
 c �̐��x�ɂ��Ắu<A HREF="#PREC">�v�Z���x�ɂ���</A>�v���Q�Ƃ��Ă��������B
 
-<LI>assign</LI><BR>
-�ȉ��̂悤�Ɏg�p���܂��B<BR>
-c = a.assign(n,f)<BR>
-f > 0 �Ȃ�Aa �� c �ɁA���̂܂ܑ�����܂��B
-f < 0 �Ȃ�A-a �� c �ɑ�����܂��B
-f �̐�Βl�i|f|�j�͂P���Q���w�肵�Ă��������B
-|f|=2 �̂Ƃ��́Ac �̍ő吸�x�� a �̎����x��菬�����Ƃ��ɂ�
-�ۂ߂��܂��B|f|=1 �̂Ƃ��͐؂�̂Ă��܂��B
-n �� c �̗L�������ł��in ���ȏ�̐��x������ c ����������܂��j�B
-
-<LI>add</LI><BR>
+</BLOCKQUOTE>
+
+<LI><B>add</B></LI><BLOCKQUOTE>
 �ȉ��̂悤�Ɏg�p���܂��B<BR>
 c = a.add(b,n)<BR>
 c = a + b ���ő�� n ���܂Ōv�Z���܂��B
 a + b �̐��x�� n ���傫���Ƃ��͊ۂ߂��܂��B
 
-<LI>sub</LI><BR>
+</BLOCKQUOTE>
+<LI><B>sub</B></LI><BLOCKQUOTE>
 �ȉ��̂悤�Ɏg�p���܂��B<BR>
 c = a.sub(b,n)<BR>
 c = a - b ���ő�� n ���܂Ōv�Z���܂��B
 a - b �̐��x�� n ���傫���Ƃ��͊ۂ߂��܂��B
 
-<LI>mult</LI><BR>
+</BLOCKQUOTE>
+<LI><B>mult</B></LI><BLOCKQUOTE>
 �ȉ��̂悤�Ɏg�p���܂��B<BR>
 c = a.mult(b,n)<BR>
 c = a * b ���ő�� n ���܂Ōv�Z���܂��B
 a * b �̐��x�� n ���傫���Ƃ��͊ۂ߂��܂��B
 
-<LI>div</LI><BR>
+</BLOCKQUOTE>
+<LI><B>div</B></LI><BLOCKQUOTE>
 �ȉ��̂悤�Ɏg�p���܂��B<BR>
 c,r = a.div(b,n)<BR>
 c=a/b �̌v�Z�����܂��B r �ɂ͏�]���������܂��Ba/b��
@@ -220,63 +261,91 @@ c=a/b �̌v�Z�����܂��B r �ɂ͏�]���������܂��Ba/b��
 �ƈقȂ�Ac �͐����Ƃ͌���܂���B
 �܂��A c �͊ۂ߂��邱�Ƃ͂���܂���B
  a = c*b + r �̊֌W�͐������܂��B
-<LI>%</LI><BR>
+</BLOCKQUOTE>
+<LI><B>%</B></LI><BLOCKQUOTE>
 r = a%b <BR>
 a/b �̗]����v�Z���܂��B�ȉ��̌v�Z�Ɠ������̂ł��B<BR>
 r = a-((a/b).floor)*b<BR>
-<LI>fix</LI><BR>
+</BLOCKQUOTE>
+<LI><B>fix</B></LI><BLOCKQUOTE>
 a �̏����_�ȉ��̐؂�̂āB<BR>
 c = a.fix
-<LI>frac</LI><BR>
+</BLOCKQUOTE>
+<LI><B>frac</B></LI><BLOCKQUOTE>
 a �̐��������̐؂�̂āB<BR>
 c = a.frac
-<LI>floor</LI><BR>
-a �ȉ��̍ő吮����\���l�iBigDecimal �l�j��Ԃ��܂��B<BR>
+</BLOCKQUOTE>
+
+<LI><B>floor[(n)]</B></LI><BLOCKQUOTE>
 c = a.floor<BR>
-�ȉ��̂悤�Ɉ�����^���āA�����_�ȉ� n+1 �ʂ̐����𑀍삷�邱�Ƃ��ł��܂�
-(�����_�ȉ����A�ő� n ���ɂ��܂�)�B<BR>
-c = BigDecimal("1.23456")<BR>
-d = c.floor(4) # d = 1.2345 �ɂȂ�܂��B<BR>
- n �����̂Ƃ��͏����_�ȏ� n ���ڂ𑀍삵�܂��B<BR>
-c = BigDecimal("15.23456")<BR>
-d = c.floor(-1) # d = 10.0 �ɂȂ�܂��B<BR>
-
-<LI>ceil</LI><BR>
-a �ȏ�̐����̂����A�ł��������������v�Z���A���̒l�iBigDecimal �l�j��Ԃ��܂��B<BR>
+a �ȉ��̍ő吮���iBigDecimal �l�j��Ԃ��܂��B
+<PRE><CODE>
+c = BigDecimal("1.23456").floor  #  ==> 1
+c = BigDecimal("-1.23456").floor #  ==> -2
+</CODE></PRE>
+�ȉ��̂悤�Ɉ��� n ��^���邱�Ƃ��ł��܂��B<BR>
+n>=0 �Ȃ�A�����_�ȉ� n+1 �ʂ̐����𑀍삵�܂�(�����_�ȉ����A�ő� n ���ɂ��܂�)�B<BR>
+n �����̂Ƃ��͏����_�ȏ� n ���ڂ𑀍삵�܂�(�����_�ʒu���獶�ɏ��Ȃ��Ƃ� n �� 0 �����т܂�)�B<BR>
+<PRE><CODE>
+ c = BigDecimal::new("1.23456").floor(4)   #  ==> 1.2345
+ c = BigDecimal::new("15.23456").floor(-1) #  ==> 10.0
+</CODE></PRE>
+
+</BLOCKQUOTE>
+<LI><B>ceil[(n)]</B></LI><BLOCKQUOTE>
 c = a.ceil<BR>
-�ȉ��̂悤�Ɉ�����^���āA�����_�ȉ� n+1 �ʂ̐����𑀍삷�邱�Ƃ��ł��܂�
-(�����_�ȉ����A�ő� n ���ɂ��܂�)�B<BR>
-c = BigDecimal::new("1.23456")<BR>
-d = c.ceil(4) # d = 1.2346 �ɂȂ�܂��B<BR>
- n �����̂Ƃ��͏����_�ȏ� n ���ڂ��𑀍삵�܂��B<BR>
-c = BigDecimal::new("15.23456")<BR>
-d = c.ceil(-1) # d = 20.0 �ɂȂ�܂��B<BR>
-
-<LI>round</LI><BR>
-�����_�ȉ����ʂ̐����l�̌ܓ����Đ����iBigDecimal �l�j�ɂ��܂��B<BR>
+a �ȏ�̐����̂����A�ł��������������v�Z���A���̒l�iBigDecimal �l�j��Ԃ��܂��B
+<PRE><CODE>
+c = BigDecimal("1.23456").ceil  #  ==> 2
+c = BigDecimal("-1.23456").ceil #  ==> -1
+</CODE></PRE>
+
+�ȉ��̂悤�Ɉ�����^���āA�����_�ȉ� n+1 �ʂ̐����𑀍삷�邱�Ƃ��ł��܂��B<BR>
+n>=0 �Ȃ�A�����_�ȉ� n+1 �ʂ̐����𑀍삵�܂�(�����_�ȉ����A�ő� n ���ɂ��܂�)�B<BR>
+ n �����̂Ƃ��͏����_�ȏ� n ���ڂ��𑀍삵�܂�(�����_�ʒu���獶�ɏ��Ȃ��Ƃ� n �� 0 �����т܂�)�B<BR>
+<PRE><CODE>
+ c = BigDecimal::new("1.23456").ceil(4)   # ==> 1.2346
+ c = BigDecimal::new("15.23456").ceil(-1) # ==> 20.0
+</CODE></PRE>
+
+</BLOCKQUOTE>
+<LI><B>round[(n[,b])]</B></LI><BLOCKQUOTE>
 c = a.round<BR>
-�ȉ��̂悤�Ɉ�����^���āA�����_�ȉ� n+1 �ʂ̐����𑀍삷�邱�Ƃ��ł��܂�
-(�����_�ȉ����A�ő� n ���ɂ��܂�)�B<BR>
-n �����̎��́A�����_�ȉ� n+1 �ʂ̐������l�̌ܓ����܂��B
-c = BigDecimal::new("1.23456")<BR>
-d = c.round(4)  # d = 1.235 �ɂȂ�܂��B<BR>
- n �����̂Ƃ��͏����_�ȏ� n ���ڂ��𑀍삵�܂��B<BR>
-c = BigDecimal::new("15.23456")<BR>
-d = c.round(-1) # d = 20.0 �ɂȂ�܂��B<BR>
-
-<LI>truncate</LI><BR>
-�����_�ȉ��̐���؂�̂ĂĐ����iBigDecimal �l�j�ɂ��܂��B<BR>
+�����_�ȉ����ʂ̐����l�̌ܓ����Đ����iBigDecimal �l�j�ɂ��܂��B<BR>
+<PRE><CODE>
+ c = BigDecimal("1.23456").round  #  ==> 1
+ c = BigDecimal("-1.23456").round #  ==> -1
+</CODE></PRE>
+
+�ȉ��̂悤�Ɉ�����^���āA�����_�ȉ� n+1 �ʂ̐����𑀍삷�邱�Ƃ��ł��܂��B<BR>
+n �����̎��́A�����_�ȉ� n+1 �ʂ̐������l�̌ܓ����܂�(�����_�ȉ����A�ő� n ���ɂ��܂�)�B<BR>
+n �����̂Ƃ��͏����_�ȏ� n ���ڂ��𑀍삵�܂�(�����_�ʒu���獶�ɏ��Ȃ��Ƃ� n �� 0 �����т܂�)�B
+<PRE><CODE>
+c = BigDecimal::new("1.23456").round(4)   #  ==> 1.2346
+c = BigDecimal::new("15.23456").round(-1) #  ==> 20.0
+</CODE></PRE>
+�Q�Ԗڂ̈����i�f�t�H���g�� 0�j�Ƀ[���ȊO���w�肷��ƁA������ Banker's rounding �ɂȂ�܂��B<BR>
+ Banker's rounding �Ƃ́A�l�̌ܓ����鐔���� p �Ƃ��āAp &lt; 5 �Ȃ�؂�̂� p &gt; 5 �Ȃ�؂�グ�A
+p �����傤�ǂT�̂Ƃ������͐؂�グ��̐����{�P�������ɂȂ�Ƃ������؂�グ�܂��B
+<PRE><CODE>
+c = BigDecimal::new("1.23456").round(3,1)   #  ==> 1.234
+c = BigDecimal::new("1.23356").round(3,1)   #  ==> 1.234
+</CODE></PRE>
+
+</BLOCKQUOTE>
+<LI><B>truncate</B></LI><BLOCKQUOTE>
 c = a.truncate<BR>
-�ȉ��̂悤�Ɉ�����^���āA�����_�ȉ� n+1 �ʂ̐����𑀍삷�邱�Ƃ��ł��܂�
-(�����_�ȉ����A�ő� n ���ɂ��܂�)�B<BR>
-n �����̎��́A�����_�ȉ� n+1 �ʂ̐�����؂�̂Ă܂��B
-c = BigDecimal::new("1.23456")<BR>
-d = c.truncate(4)  # d = 1.2345 �ɂȂ�܂��B<BR>
- n �����̂Ƃ��͏����_�ȏ� n ���ڂ��𑀍삵�܂��B<BR>
-c = BigDecimal::new("15.23456")<BR>
-d = c.truncate(-1) # d = 10.0 �ɂȂ�܂��B<BR>
-
-<LI>divmod</LI><BR>
+�����_�ȉ��̐���؂�̂ĂĐ����iBigDecimal �l�j�ɂ��܂��B<BR>
+�ȉ��̂悤�Ɉ�����^���āA�����_�ȉ� n+1 �ʂ̐����𑀍삷�邱�Ƃ��ł��܂��B<BR>
+n �����̎��́A�����_�ȉ� n+1 �ʂ̐�����؂�̂Ă܂�(�����_�ȉ����A�ő� n ���ɂ��܂�)�B
+n �����̂Ƃ��͏����_�ȏ� n ���ڂ��𑀍삵�܂�(�����_�ʒu���獶�ɏ��Ȃ��Ƃ� n �� 0 �����т܂�)�B<BR>
+<PRE><CODE>
+c = BigDecimal::new("1.23456").truncate(4)   #  ==> 1.2345
+c = BigDecimal::new("15.23456").truncate(-1) #  ==> 10.0
+</CODE></PRE>
+
+</BLOCKQUOTE>
+<LI><B>divmod</B></LI><BLOCKQUOTE>
 ���Ə�]�̔z���Ԃ��܂��B<BR>
 c,r = a.divmod(b) # a = c*b + r<BR>
 divmod���\�b�h�� a = c * b + r �ƂȂ� a / b �̕��������_�^�̏� c �Ə�] r ��
@@ -284,85 +353,44 @@ divmod���\�b�h�� a = c * b + r �ƂȂ� a / b �̕��������_�^�̏� c �Ə�] r ��
 c = (a/b).floor <BR>
 r = a - c*b<BR>
 �Ōv�Z����܂��B
-<LI>remainder</LI><BR>
+</BLOCKQUOTE>
+<LI><B>remainder</B></LI><BLOCKQUOTE>
 r=a.remainder(b)<BR>
 a/b �̏�] r ���v�Z���܂��B<BR>
 c = (a/b).fix <BR>
 r = a - c*b<BR>
 �Ōv�Z����܂��B
 
-<LI>abs</LI><BR>
+</BLOCKQUOTE>
+<LI><B>abs</B></LI><BLOCKQUOTE>
 ���̐�Βl<BR>
 c = a.abs<BR>
 
-<LI>to_i</LI><BR>
+</BLOCKQUOTE>
+<LI><B>to_i</B></LI><BLOCKQUOTE>
 �����_�ȉ���؂�̂ĂĐ����ɕϊ����܂��B<BR>
 i = a.to_i<BR>
 i �͒l�ɉ����� Fixnum �� Bignum �ɂȂ�܂��B
 a �� Infinity �� NaN �̂Ƃ��Ai �� nil �ɂȂ�܂��B
-<LI>to_f</LI><BR>
+</BLOCKQUOTE>
+<LI><B>to_f</B></LI><BLOCKQUOTE>
 dup �ƑS�������ł��B
 �����l�� BigDecimal �I�u�W�F�N�g�𐶐����܂��B
-<LI>to_s[(n)]</LI><BR>
+</BLOCKQUOTE>
+<LI><B>to_s[(n)]</B></LI><BLOCKQUOTE>
 ������ɕϊ����܂�("0.xxxxxEn"�̌`�ɂȂ�܂��j�B<BR>
 s = a.to_s<BR>
 n ���w�肳�ꂽ�Ƃ��́A���������� n �����ɋ󔒂ŋ�؂�܂��B<BR>
 s = a.to_s(n)
-<LI>exponent</LI><BR>
+</BLOCKQUOTE>
+<LI><B>exponent</B></LI><BLOCKQUOTE>
 �w�����𐮐��l�ŕԂ��܂��B
 n = a.exponent <BR>
 �� a �̒l�� 0.xxxxxxx*10**n ���Ӗ����܂��B
 
-<LI>E</LI><BR>
-���R�ΐ��̒�e(=2.718281828....)���v�Z���܂��i�����Ƀe�C���[�W�J�Łj�B<BR>
-e = BigDecimal::E(n)<BR>
-n�͕K�v�ȗL�������𐮐��Ŏw�肵�܂��B
-<LI>PI</LI><BR>
-�~����(=3.14159265358979....)���v�Z���܂��iJ�DMachin�̌�����p���܂��j�B<BR>
-e = BigDecimal::PI(n)<BR>
-n �͕K�v�ȗL�������𐮐��Ŏw�肵�܂��B
-<LI>BASE</LI><BR>
-�����Ŏg�p������̒l�ł��B������ 32 �r�b�g�̏����n�ł�10000�ł��B<BR>
-b = BigDecimal::BASE<BR>
-<LI>mode</LI><BR>
-BigDecimal�̎��s���ʂ𐧌䂵�܂��B�ȉ��̎g�p���@����`����Ă��܂��B<BR>
-f = BigDecimal::mode(BigDecimal::EXCEPTION_NaN,flag)<BR>
-f = BigDecimal::mode(BigDecimal::EXCEPTION_INFINITY,flag)<BR>
-f = BigDecimal::mode(BigDecimal::EXCEPTION_UNDERFLOW,flag)<BR>
-f = BigDecimal::mode(BigDecimal::EXCEPTION_OVERFLOW,flag)<BR>
-f = BigDecimal::mode(BigDecimal::EXCEPTION_ZERODIVIDE,flag)<BR>
-f = BigDecimal::mode(BigDecimal::EXCEPTION_ALL,flag)<BR>
-
-EXCEPTION_NaN �͌��ʂ� NaN �ɂȂ����Ƃ��̎w��ł��B
-EXCEPTION_INFINITY �͌��ʂ�������(�}Infinity)
-�ɂȂ����Ƃ��̎w��ł��B
-EXCEPTION_UNDERFLOW �͎w�������A���_�[�t���[����Ƃ��̎w��ł��B
-EXCEPTION_OVERFLOW �͎w�������I�[�o�[�t���[����Ƃ��̎w��ł��B
-EXCEPTION_ZERODIVIDE �̓[���ɂ�銄��Z�����s�����Ƃ��̎w��ł��B
-EXCEPTION_ALL �́A�\�ȑS�Ăɑ΂��Ĉꊇ���Đݒ肷��Ƃ���
-�g�p���܂��B
-flag �� true �̂Ƃ��́A�w�肵����ԂɂȂ����Ƃ��ɗ�O�𔭍s
-����悤�ɂȂ�܂��B
-flag �� false�i�f�t�H���g�j�Ȃ�A��O�͔��s����܂���B�v�Z���ʂ�
-�ȉ��̂悤�ɂȂ�܂��B<BR>
-EXCEPTION_NaN �̂Ƃ��A��(NaN)<BR>
-EXCEPTION_INFINITY �̂Ƃ��A����(+ or -Infinity)<BR>
-EXCEPTION_UNDERFLOW �̂Ƃ��A�[��<BR>
-EXCEPTION_OVERFLOW �̂Ƃ��A+Infinity �� -Infinity<BR>
-EXCEPTION_ZERODIVIDE �̂Ƃ��A+Infinity �� -Infinity<BR>
-EXCEPTION_INFINITY�AEXCEPTION_OVERFLOW�AEXCEPTION_ZERODIVIDE
-�͍��̂Ƃ��듯���ł��B<BR>
-�߂�l�́A�ݒ��̒l�ł��B�u�l�v�̈Ӗ��́A�Ⴆ��
-BigDecimal::EXCEPTION_NaN�Ɓu�l�v�� & �� �[���ȊO�Ȃ��
-EXCEPTION_NaN���ݒ肳��Ă���Ƃ����Ӗ��ł��B
-flag �� nil�A�܂��́Atrue �� false �ȊO�Ȃ猻�݂̐ݒ�l���Ԃ�܂��B
+</BLOCKQUOTE>
 
-<LI>limit([n])</LI><BR>
-���������BigDecimal�I�u�W�F�N�g�̍ő包����n���ɐ������܂��B�߂�l��
-�ݒ肷��O�̒l�ł��B�ݒ�l�̃f�t�H���g�l�͂O�ŁA�����������Ƃ����Ӗ��ł��B
-n���w�肵�Ȃ��ꍇ�́A����̍ő包�����Ԃ�܂��B<BR>
-mf = BigDecimal::limit(n)<BR>
-<LI>sign</LI><BR>
+<LI><B>sign</B></LI><BLOCKQUOTE>
 �l�̑�����Ԃ��܂��B
 n = a.sign <BR>
 �Ƃ����Ƃ� n �̒l�� a ���ȉ��̂Ƃ����Ӗ����܂��B<BR>
@@ -375,26 +403,40 @@ n = BigDecimal::SIGN_NEGATIVE_FINITE(-2) : a �͕��̒l<BR>
 n = BigDecimal::SIGN_POSITIVE_INFINITE(3) : a ��+Infinity<BR>
 n = BigDecimal::SIGN_NEGATIVE_INFINITE(-3) : a ��-Infinity<BR>
 
-<LI>nan?</LI><BR>
+</BLOCKQUOTE>
+<LI><B>nan?</B></LI><BLOCKQUOTE>
 a.nan? �� a ��NaN�̂Ƃ��^��Ԃ��܂��B
-<LI>infinite?</LI><BR>
-a.infinite? �� a ��+���܂���-���̂Ƃ��^��Ԃ��܂��B
-<LI>finite?</LI><BR>
+</BLOCKQUOTE>
+<LI><B>infinite?</B></LI><BLOCKQUOTE>
+a.infinite? �� a ��+���̂Ƃ� 1 �A-���̂Ƃ��� -1�A����ȊO�̂Ƃ��� nil ��Ԃ��܂��B
+</BLOCKQUOTE>
+<LI><B>finite?</B></LI><BLOCKQUOTE>
 a.finite? �� a �����܂��� NaN �łȂ��Ƃ��^��Ԃ��܂��B
+</BLOCKQUOTE>
 
-<LI>to_parts</LI><BR>
+<LI><B>zero?</B></LI><BLOCKQUOTE>
+a �� 0 �Ȃ� true �ɂȂ�܂��B<BR>
+c = a.zero?
+</BLOCKQUOTE>
+<LI><B>nonzero?</B></LI><BLOCKQUOTE>
+a �� 0 �Ȃ� nil�A0 �ȊO�Ȃ� a ���̂��̂��Ԃ�܂��B<BR>
+c = a.nonzero?
+
+</BLOCKQUOTE>
+<LI><B>split</B></LI><BLOCKQUOTE>
 BigDecimal �l�� 0.xxxxxxx*10**n �ƕ\�������Ƃ��ɁA�����iNaN�̂Ƃ���
 0�A����ȊO��+1��-1�ɂȂ�܂��j�A
 ���������̕�����i"xxxxxxx"�j�ƁA��i10�j�A�X�Ɏw�� n ��z���
 �Ԃ��܂��B<BR>
-a=BigDecimal::new("3.14159265",10)<BR>
-f,x,y,z = a.to_parts<BR>
+a=BigDecimal::new("3.14159265")<BR>
+f,x,y,z = a.split<BR>
 �Ƃ���ƁAf=+1�Ax="314159265"�Ay=10�Az=1�ɂȂ�܂��B<BR>
 �]���āA<BR>
 s = "0."+x<BR>
 b = f*(s.to_f)*(y**z)<BR>
 �� Float �ɕϊ����邱�Ƃ��ł��܂��B
-<LI>inspect</LI><BR>
+</BLOCKQUOTE>
+<LI><B>inspect</B></LI><BLOCKQUOTE>
 �f�o�b�O�o�͂Ɏg�p����܂��B<BR>
 p a=BigDecimal::new("3.14",10)<BR>
 �Ƃ���ƁA[0x112344:'0.314E1',4(12)]�̂悤�ɏo�͂���܂��B
@@ -402,47 +444,54 @@ p a=BigDecimal::new("3.14",10)<BR>
 ����4�͌��݂̗L������(�\�����኱�傫�����Ƃ�����܂�)�A
 �Ō�̓I�u�W�F�N�g����蓾��ő包���ɂȂ�܂��B
 
-<LI>dup</LI><BR>
+</BLOCKQUOTE>
+<LI><B>dup</B></LI><BLOCKQUOTE>
 �����l�� BigDecimal �I�u�W�F�N�g�𐶐����܂��B
-<LI>sqrt</LI><BR>
+</BLOCKQUOTE>
+<LI><B>sqrt</B></LI><BLOCKQUOTE>
 a�̗L���� n ���̕������in �̕������ł͂���܂���j�B
 ����܂��A�����Ƀj���[�g���@�Ōv�Z���܂��B<BR>
 c = a.sqrt(n)<BR>
-<LI>sincos</LI><BR>
+</BLOCKQUOTE>
+<LI><B>sincos</B></LI><BLOCKQUOTE>
 a �̗L���� n ���� sin �� cos �𓯎��Ɂi�e�C���[�W�J�Łj�v�Z���āA
  sin �� cos �̔z���Ԃ��܂��B
 n �͕K�v�ȗL�������ł��i n �� sin �� cos ���v�Z����킯�ł͂���܂���j�B
 <BR>
 sin,cos = a.sincos(n)<BR>
 |a|<2*3.1415....�łȂ��Ɛ������������v�Z�ł��Ȃ����Ƃ�����܂��B
-<LI>exp</LI><BR>
+</BLOCKQUOTE>
+<LI><B>exp</B></LI><BLOCKQUOTE>
 ���R�ΐ��̒�e(=2.718281828....)�� a ����v�Z���܂��B<BR>
 c = a.exp(n)<BR>
 n �͕K�v�ȗL�������ł��B
-<LI>power</LI><BR>
+</BLOCKQUOTE>
+<LI><B>**</B></LI><BLOCKQUOTE>
 a �� n ����v�Z���܂��B���͐����B<BR>
+c = a ** n<BR>
+���ʂƂ��� c �̗L������ a �� n �{�ȏ�ɂȂ�̂Œ��ӁB
+</BLOCKQUOTE>
+<LI><B>power</B></LI><BLOCKQUOTE>
+** �Ɠ����ŁAa �� n ����v�Z���܂��B���͐����B<BR>
 c = a.power(n)<BR>
 ���ʂƂ��� c �̗L������ a �� n �{�ȏ�ɂȂ�̂Œ��ӁB
-<LI>zero?</LI><BR>
-a �� 0 �Ȃ� true �ɂȂ�܂��B<BR>
-c = a.zero?<BR>
-<LI>nonzero?</LI><BR>
-a �� 0 �Ȃ� false�A0 �ȊO�Ȃ� a ���̂��̂��Ԃ�܂��B<BR>
-c = a.nonzero?<BR>
-<LI>&lt=&gt</LI><BR>
+</BLOCKQUOTE>
+
+<LI><B>&lt=&gt</B></LI><BLOCKQUOTE>
 a==b �Ȃ� 0�Aa &gt b �Ȃ� 1�Aa &lt b �Ȃ� -1 �ɂȂ�܂��B<BR>
-c = a &lt=&gt b <BR>
+c = a &lt=&gt b 
+</BLOCKQUOTE>
 </UL>
 ��́A�ǂ�Ŏ��̔@���ł��B<BR>
 <UL>
-<LI>==</LI>
-<LI>===</LI>
+<LI><B>==</B></LI>
+<LI><B>===</B></LI>
 �u==�v�Ɠ����ł��� case ���Ŏg�p����܂��B
-<LI>!=</LI>
-<LI>&lt</LI>
-<LI>&lt=</LI>
-<LI>&gt</LI>
-<LI>&gt=</LI>
+<LI><B>!=</B></LI>
+<LI><B>&lt</B></LI>
+<LI><B>&lt=</B></LI>
+<LI><B>&gt</B></LI>
+<LI><B>&gt=</B></LI>
 </UL>
 <H3>coerce�ɂ���</H3>
 BigDecimal �I�u�W�F�N�g���Z�p���Z�q�̍��ɂ���Ƃ��́ABigDecimal �I�u�W�F�N�g��
author	shigek <shigek@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>	2003-06-27 04:38:57 +0000
committer	shigek <shigek@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>	2003-06-27 04:38:57 +0000
commit	d3ce235babf3a5fa9a7904c45ec193e8962fe845 (patch)
tree	6d2a550cb79cddaee7a52a6aae149d1b3f0d3c16 /ext/bigdecimal
parent	7e91b4b546634afa0203f7bd6d0e5092f8f7ee61 (diff)