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* random.c: Bugfix: Retrieve and store most significant 32 bits in

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different order if the machine is bigendian.
(scm_init_random): Added safety check for bignum digit size.
This commit is contained in:
Mikael Djurfeldt 1999-01-21 02:13:23 +00:00
parent 6bcb5a82c3
commit 2a0279c9b8
1 changed files with 21 additions and 0 deletions
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21
libguile/random.c
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@ -247,7 +247,11 @@ scm_i_random_bignum (SCM m, scm_rstate *state)
#endif #endif
{ {
/* fix most significant 32 bits */ /* fix most significant 32 bits */
#if SIZEOF_INT == 4 && defined (WORDS_BIGENDIAN)
w = SCM_BDIGITS (m)[nd - 1] << 16 | SCM_BDIGITS (m)[nd - 2];
#else
w = ((LONG32 *) SCM_BDIGITS (m))[nd / 2 - 1]; w = ((LONG32 *) SCM_BDIGITS (m))[nd / 2 - 1];
#endif
mask = (w < 0x10000 mask = (w < 0x10000
? (w < 0x100 ? (w < 0x100
? scm_masktab[w] ? scm_masktab[w]
@ -274,7 +278,12 @@ scm_i_random_bignum (SCM m, scm_rstate *state)
{ {
/* fix most significant 32 bits */ /* fix most significant 32 bits */
i /= 2; i /= 2;
#if SIZEOF_INT == 4 && defined (WORDS_BIGENDIAN)
w = scm_the_rng.random_bits (state) & mask;
bits[--i] = (w & 0xffff) << 16 | w >> 16;
#else
bits[--i] = scm_the_rng.random_bits (state) & mask; bits[--i] = scm_the_rng.random_bits (state) & mask;
#endif
} }
/* now fill up the rest of the bignum */ /* now fill up the rest of the bignum */
while (i) while (i)
@ -553,5 +562,17 @@ scm_init_random ()
#include "random.x" #include "random.x"
/* Check that the assumptions about bits per bignum digit are correct. */
#if SIZEOF_INT == 4
m = 16;
#else
m = 32;
#endif
if (m != SCM_BITSPERDIG)
{
fprintf (stderr, "Internal inconsistency: Confused about bignum digit size in random.c\n");
exit (1);
}
scm_add_feature ("random"); scm_add_feature ("random");
} }