diff options
Diffstat (limited to 'bignum.c')
| -rw-r--r-- | bignum.c | 14 |
1 files changed, 14 insertions, 0 deletions
@@ -308,6 +308,19 @@ rb_int2inum(SIGNED_VALUE n) # error unexpected SIZEOF_LONG : SIZEOF_BDIGITS ratio #endif +/* + * buf is an array of long integers. + * buf is ordered from least significant word to most significant word. + * buf[0] is the least significant word and + * buf[num_longs-1] is the most significant word. + * This means words in buf is little endian. + * However each word in buf is native endian. + * (buf[i]&1) is the least significant bit and + * (buf[i]&(1<<(SIZEOF_LONG*CHAR_BIT-1))) is the most significant bit + * for each 0 <= i < num_longs. + * So buf is little endian at whole on a little endian machine. + * But buf is mixed endian on a big endian machine. + */ void rb_big_pack(VALUE val, unsigned long *buf, long num_longs) { @@ -349,6 +362,7 @@ rb_big_pack(VALUE val, unsigned long *buf, long num_longs) } } +/* See rb_big_pack comment for endianness of buf. */ VALUE rb_big_unpack(unsigned long *buf, long num_longs) { |