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/*
* Utility compute operations used by translated code.
*
* Copyright (c) 2003 Fabrice Bellard
* Copyright (c) 2007 Aurelien Jarno
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "qemu/host-utils.h"
#ifndef CONFIG_INT128
/* Long integer helpers */
static inline void mul64(uint64_t *plow, uint64_t *phigh,
uint64_t a, uint64_t b)
{
typedef union {
uint64_t ll;
struct {
#ifdef HOST_WORDS_BIGENDIAN
uint32_t high, low;
#else
uint32_t low, high;
#endif
} l;
} LL;
LL rl, rm, rn, rh, a0, b0;
uint64_t c;
a0.ll = a;
b0.ll = b;
rl.ll = (uint64_t)a0.l.low * b0.l.low;
rm.ll = (uint64_t)a0.l.low * b0.l.high;
rn.ll = (uint64_t)a0.l.high * b0.l.low;
rh.ll = (uint64_t)a0.l.high * b0.l.high;
c = (uint64_t)rl.l.high + rm.l.low + rn.l.low;
rl.l.high = c;
c >>= 32;
c = c + rm.l.high + rn.l.high + rh.l.low;
rh.l.low = c;
rh.l.high += (uint32_t)(c >> 32);
*plow = rl.ll;
*phigh = rh.ll;
}
/* Unsigned 64x64 -> 128 multiplication */
void mulu64 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)
{
mul64(plow, phigh, a, b);
}
/* Signed 64x64 -> 128 multiplication */
void muls64 (uint64_t *plow, uint64_t *phigh, int64_t a, int64_t b)
{
uint64_t rh;
mul64(plow, &rh, a, b);
/* Adjust for signs. */
if (b < 0) {
rh -= a;
}
if (a < 0) {
rh -= b;
}
*phigh = rh;
}
/*
* Unsigned 128-by-64 division. Returns quotient via plow and
* remainder via phigh.
* The result must fit in 64 bits (plow) - otherwise, the result
* is undefined.
* This function will cause a division by zero if passed a zero divisor.
*/
void divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor)
{
uint64_t dhi = *phigh;
uint64_t dlo = *plow;
unsigned i;
uint64_t carry = 0;
if (divisor == 0 || dhi == 0) {
*plow = dlo / divisor;
*phigh = dlo % divisor;
} else {
for (i = 0; i < 64; i++) {
carry = dhi >> 63;
dhi = (dhi << 1) | (dlo >> 63);
if (carry || (dhi >= divisor)) {
dhi -= divisor;
carry = 1;
} else {
carry = 0;
}
dlo = (dlo << 1) | carry;
}
*plow = dlo;
*phigh = dhi;
}
}
/*
* Signed 128-by-64 division. Returns quotient via plow and
* remainder via phigh.
* The result must fit in 64 bits (plow) - otherwise, the result
* is undefined.
* This function will cause a division by zero if passed a zero divisor.
*/
void divs128(int64_t *plow, int64_t *phigh, int64_t divisor)
{
int sgn_dvdnd = *phigh < 0;
int sgn_divsr = divisor < 0;
if (sgn_dvdnd) {
*plow = ~(*plow);
*phigh = ~(*phigh);
if (*plow == (int64_t)-1) {
*plow = 0;
(*phigh)++;
} else {
(*plow)++;
}
}
if (sgn_divsr) {
divisor = 0 - divisor;
}
divu128((uint64_t *)plow, (uint64_t *)phigh, (uint64_t)divisor);
if (sgn_dvdnd ^ sgn_divsr) {
*plow = 0 - *plow;
}
}
#endif
/**
* urshift - 128-bit Unsigned Right Shift.
* @plow: in/out - lower 64-bit integer.
* @phigh: in/out - higher 64-bit integer.
* @shift: in - bytes to shift, between 0 and 127.
*
* Result is zero-extended and stored in plow/phigh, which are
* input/output variables. Shift values outside the range will
* be mod to 128. In other words, the caller is responsible to
* verify/assert both the shift range and plow/phigh pointers.
*/
void urshift(uint64_t *plow, uint64_t *phigh, int32_t shift)
{
shift &= 127;
if (shift == 0) {
return;
}
uint64_t h = *phigh >> (shift & 63);
if (shift >= 64) {
*plow = h;
*phigh = 0;
} else {
*plow = (*plow >> (shift & 63)) | (*phigh << (64 - (shift & 63)));
*phigh = h;
}
}
/**
* ulshift - 128-bit Unsigned Left Shift.
* @plow: in/out - lower 64-bit integer.
* @phigh: in/out - higher 64-bit integer.
* @shift: in - bytes to shift, between 0 and 127.
* @overflow: out - true if any 1-bit is shifted out.
*
* Result is zero-extended and stored in plow/phigh, which are
* input/output variables. Shift values outside the range will
* be mod to 128. In other words, the caller is responsible to
* verify/assert both the shift range and plow/phigh pointers.
*/
void ulshift(uint64_t *plow, uint64_t *phigh, int32_t shift, bool *overflow)
{
uint64_t low = *plow;
uint64_t high = *phigh;
shift &= 127;
if (shift == 0) {
return;
}
/* check if any bit will be shifted out */
urshift(&low, &high, 128 - shift);
if (low | high) {
*overflow = true;
}
if (shift >= 64) {
*phigh = *plow << (shift & 63);
*plow = 0;
} else {
*phigh = (*plow >> (64 - (shift & 63))) | (*phigh << (shift & 63));
*plow = *plow << shift;
}
}
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