diff options
Diffstat (limited to 'third_party/heimdal/lib/hcrypto/libtommath/bn_mp_log_u32.c')
| -rw-r--r-- | third_party/heimdal/lib/hcrypto/libtommath/bn_mp_log_u32.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_log_u32.c b/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_log_u32.c index f7bca01ded3..c9cc157911e 100644 --- a/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_log_u32.c +++ b/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_log_u32.c @@ -91,13 +91,24 @@ mp_err mp_log_u32(const mp_int *a, uint32_t base, uint32_t *c) return MP_VAL; } + /* `base' is at least 2 */ + /* A small shortcut for bases that are powers of two. */ if ((base & (base - 1u)) == 0u) { int y, bit_count; + for (y=0; (y < 7) && ((base & 1u) == 0u); y++) { + /* We must go through this loop at least once */ base >>= 1; } bit_count = mp_count_bits(a) - 1; + /* + * `y' is necessarily at least 1 because `base' is a power of two and + * larger than 1, so we must have gone through the loop at least once, so + * we can't be dividing by zero. + * + * scan-build thinks we can be dividing by zero... WAT. + */ *c = (uint32_t)(bit_count/y); return MP_OKAY; } |