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Merge pull request #3125 from SparkiDev/mp_leading_bit 

Change mp_leading_bit (integer.c) to not to require a copy
pull/3142/head
toddouska 2020-07-16 11:05:09 -07:00 committed by GitHub
parent 859a1eebe4 e754076c37
commit 50f228af0a
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 3 additions and 16 deletions
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19
wolfcrypt/src/integer.c
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@ -271,23 +271,10 @@ int mp_count_bits (mp_int * a)
int mp_leading_bit (mp_int * a) int mp_leading_bit (mp_int * a)
{ {
int bit = 0; int c = mp_count_bits(a);
mp_int t;
if (mp_init_copy(&t, a) != MP_OKAY) if (c == 0) return 0;
return 0; return (c % 8) == 0;
while (mp_iszero(&t) == MP_NO) {
#ifndef MP_8BIT
bit = (t.dp[0] & 0x80) != 0;
#else
bit = ((t.dp[0] | ((t.dp[1] & 0x01) << 7)) & 0x80) != 0;
#endif
if (mp_div_2d (&t, 8, &t, NULL) != MP_OKAY)
break;
}
mp_clear(&t);
return bit;
} }
int mp_to_unsigned_bin_at_pos(int x, mp_int *t, unsigned char *b) int mp_to_unsigned_bin_at_pos(int x, mp_int *t, unsigned char *b)