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#ifndef _ARITH_C_ /* -*- linux-c -*- */
#define _ARITH_C_
/** @file arith.
* @brief Implements 64-bit signed division/multiplication.
*/
struct context;
void _stp_divmod64 (unsigned *errorcount, int64_t x, int64_t y,
int64_t *quo, int64_t *rem);
/** Divide x by y. In case of overflow or division-by-zero,
* increment context errorcount, and return any old value.
*/
inline int64_t _stp_div64 (unsigned *errorcount, int64_t x, int64_t y)
{
if (likely ((x >= LONG_MIN && x <= LONG_MAX) &&
(y >= LONG_MIN && y <= LONG_MAX)))
{
long xx = (long) x;
long yy = (long) y;
// check for division-by-zero and overflow
if (unlikely (yy == 0 || (xx == LONG_MIN && yy == -1)))
{
(*errorcount) ++;
return 0;
}
return xx / yy;
}
else
{
int64_t quo = 0;
_stp_divmod64 (errorcount, x, y, &quo, NULL);
return quo;
}
}
/** Modulo x by y. In case of overflow or division-by-zero,
* increment context errorcount, and return any old value.
*/
inline int64_t _stp_mod64 (unsigned *errorcount, int64_t x, int64_t y)
{
if (likely ((x >= LONG_MIN && x <= LONG_MAX) &&
(y >= LONG_MIN && y <= LONG_MAX)))
{
long xx = (long) x;
long yy = (long) y;
// check for division-by-zero and overflow
if (unlikely (yy == 0 || (xx == LONG_MIN && yy == -1)))
{
(*errorcount) ++;
return 0;
}
return xx % yy;
}
else
{
int64_t rem = 0;
_stp_divmod64 (errorcount, x, y, NULL, &rem);
return rem;
}
}
/** Perform general long division/modulus. */
void _stp_divmod64 (unsigned *errorcount, int64_t x, int64_t y,
int64_t *quo, int64_t *rem)
{
// XXX: wimp out for now
(*errorcount) ++;
if (quo) *quo = 0;
if (rem) *rem = 0;
}
#endif /* _ARITH_C_ */
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