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mpint: fix further integer-type confusions.

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This makes the test suite pass if I compile with -DBIGNUM_OVERRIDE=4
to fall back to 16-bit BignumInt. In that mode, BignumInt is smaller
than 'int', which means default promotion keeps causing things to get
promoted to 'int' unexpectedly, so I had to add some casts back down.
This commit is contained in:
Simon Tatham 2019-01-07 20:04:06 +00:00
parent 55ea49de1e
commit 7fd815014e
1 changed files with 11 additions and 5 deletions
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16
mpint.c
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@ -1,4 +1,5 @@
#include <assert.h> #include <assert.h>
#include <limits.h>
#include <stdio.h> #include <stdio.h>
#include "defs.h" #include "defs.h"
@ -8,6 +9,8 @@
#include "mpint.h" #include "mpint.h"
#include "mpint_i.h" #include "mpint_i.h"
#define SIZE_T_BITS (CHAR_BIT * sizeof(size_t))
/* /*
* Inline helpers to take min and max of size_t values, used * Inline helpers to take min and max of size_t values, used
* throughout this code. * throughout this code.
@ -212,8 +215,10 @@ mp_int *mp_from_hex_pl(ptrlen hex)
for (size_t nibble = 0; nibble < hex.len; nibble++) { for (size_t nibble = 0; nibble < hex.len; nibble++) {
BignumInt digit = ((char *)hex.ptr)[hex.len-1 - nibble]; BignumInt digit = ((char *)hex.ptr)[hex.len-1 - nibble];
BignumInt lmask = ~-(((digit-'a')|('f'-digit)) >> (BIGNUM_INT_BITS-1)); BignumInt lmask = ~-((BignumInt)((digit-'a')|('f'-digit))
BignumInt umask = ~-(((digit-'A')|('F'-digit)) >> (BIGNUM_INT_BITS-1)); >> (BIGNUM_INT_BITS-1));
BignumInt umask = ~-((BignumInt)((digit-'A')|('F'-digit))
>> (BIGNUM_INT_BITS-1));
BignumInt digitval = digit - '0'; BignumInt digitval = digit - '0';
digitval ^= (digitval ^ (digit - 'a' + 10)) & lmask; digitval ^= (digitval ^ (digit - 'a' + 10)) & lmask;
@ -267,7 +272,7 @@ void mp_set_bit(mp_int *x, size_t bit, unsigned val)
static inline unsigned normalise_to_1(BignumInt n) static inline unsigned normalise_to_1(BignumInt n)
{ {
n = (n >> 1) | (n & 1); /* ensure top bit is clear */ n = (n >> 1) | (n & 1); /* ensure top bit is clear */
n = (-n) >> (BIGNUM_INT_BITS - 1); /* normalise to 0 or 1 */ n = (BignumInt)(-n) >> (BIGNUM_INT_BITS - 1); /* normalise to 0 or 1 */
return n; return n;
} }
static inline unsigned normalise_to_1_u64(uint64_t n) static inline unsigned normalise_to_1_u64(uint64_t n)
@ -331,7 +336,8 @@ size_t mp_get_nbits(mp_int *x)
BignumInt hibit_index = 0; BignumInt hibit_index = 0;
for (size_t i = (1 << (BIGNUM_INT_BITS_BITS-1)); i != 0; i >>= 1) { for (size_t i = (1 << (BIGNUM_INT_BITS_BITS-1)); i != 0; i >>= 1) {
BignumInt shifted_word = hiword >> i; BignumInt shifted_word = hiword >> i;
BignumInt indicator = (-shifted_word) >> (BIGNUM_INT_BITS-1); BignumInt indicator =
(BignumInt)(-shifted_word) >> (BIGNUM_INT_BITS-1);
hiword ^= (shifted_word ^ hiword ) & -indicator; hiword ^= (shifted_word ^ hiword ) & -indicator;
hibit_index += i & -(size_t)indicator; hibit_index += i & -(size_t)indicator;
} }
@ -361,7 +367,7 @@ static void trim_leading_zeroes(char *buf, size_t bufsize, size_t maxtrim)
if (trim > 0) { if (trim > 0) {
for (size_t pos = trim; pos-- > 0 ;) { for (size_t pos = trim; pos-- > 0 ;) {
uint8_t diff = buf[pos] ^ '0'; uint8_t diff = buf[pos] ^ '0';
size_t mask = -((((size_t)diff) - 1) >> (BIGNUM_INT_BITS - 1)); size_t mask = -((((size_t)diff) - 1) >> (SIZE_T_BITS - 1));
trim ^= (trim ^ pos) & ~mask; trim ^= (trim ^ pos) & ~mask;
} }
} }