From 1f57a334daa4cd27decdc756cd709163e00e6a0c Mon Sep 17 00:00:00 2001
From: naruse <naruse@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Fri, 5 Feb 2016 04:31:27 +0000
Subject: * insns.def (opt_mult): Use int128_t for overflow detection.

* bignum.c (rb_uint128t2big): added for opt_mult.

* bignum.c (rb_uint128t2big): added for rb_uint128t2big..

* configure.in: define int128_t, uint128_t and related MACROs.
  Initially introduced by r41379 but reverted by r50749.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53741 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 bignum.c | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

(limited to 'bignum.c')

diff --git a/bignum.c b/bignum.c
index afd264adec..bc24764b88 100644
--- a/bignum.c
+++ b/bignum.c
@@ -4367,6 +4367,46 @@ rb_ll2inum(LONG_LONG n)
 
 #endif  /* HAVE_LONG_LONG */
 
+#ifdef HAVE_INT128_T
+static VALUE
+rb_uint128t2big(uint128_t n)
+{
+    long i;
+    VALUE big = bignew(bdigit_roomof(SIZEOF_INT128_T), 1);
+    BDIGIT *digits = BDIGITS(big);
+
+    for (i = 0; i < bdigit_roomof(SIZEOF_INT128_T); i++) {
+	digits[i] = BIGLO(RSHIFT(n ,BITSPERDIG*i));
+    }
+
+    i = bdigit_roomof(SIZEOF_INT128_T);
+    while (i-- && !digits[i]) ;
+    BIGNUM_SET_LEN(big, i+1);
+    return big;
+}
+
+VALUE
+rb_int128t2big(int128_t n)
+{
+    int neg = 0;
+    uint128_t u;
+    VALUE big;
+
+    if (n < 0) {
+        u = 1 + (uint128_t)(-(n + 1)); /* u = -n avoiding overflow */
+	neg = 1;
+    }
+    else {
+        u = n;
+    }
+    big = rb_uint128t2big(u);
+    if (neg) {
+	BIGNUM_SET_SIGN(big, 0);
+    }
+    return big;
+}
+#endif
+
 VALUE
 rb_cstr2inum(const char *str, int base)
 {
-- 
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