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Restore a more maintainable version of the 64bit multiply code.

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git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3439 c046a42c-6fe2-441c-8c8c-71466251a162
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ths 2007-10-25 23:00:03 +00:00
parent 86f1d3ac73
commit e494ead521
1 changed files with 75 additions and 40 deletions
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115
host-utils.c
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@ -1,6 +1,7 @@
/*
* 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
@ -24,54 +25,88 @@
#include "vl.h"
/* Signed 64x64 -> 128 multiplication */
void muls64(int64_t *phigh, int64_t *plow, int64_t a, int64_t b)
/* Long integer helpers */
static void add128 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)
{
#if defined(__x86_64__)
__asm__ ("imul %0\n\t"
: "=d" (*phigh), "=a" (*plow)
: "a" (a), "0" (b)
);
#else
int64_t ph;
uint64_t pm1, pm2, pl;
pl = (uint64_t)((uint32_t)a) * (uint64_t)((uint32_t)b);
pm1 = (a >> 32) * (uint32_t)b;
pm2 = (uint32_t)a * (b >> 32);
ph = (a >> 32) * (b >> 32);
ph += (int64_t)pm1 >> 32;
ph += (int64_t)pm2 >> 32;
pm1 = (uint64_t)((uint32_t)pm1) + (uint64_t)((uint32_t)pm2) + (pl >> 32);
*phigh = ph + ((int64_t)pm1 >> 32);
*plow = (pm1 << 32) + (uint32_t)pl;
#endif
*plow += a;
/* carry test */
if (*plow < a)
(*phigh)++;
*phigh += b;
}
static void neg128 (uint64_t *plow, uint64_t *phigh)
{
*plow = ~*plow;
*phigh = ~*phigh;
add128(plow, phigh, 1, 0);
}
static void mul64 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)
{
uint32_t a0, a1, b0, b1;
uint64_t v;
a0 = a;
a1 = a >> 32;
b0 = b;
b1 = b >> 32;
v = (uint64_t)a0 * (uint64_t)b0;
*plow = v;
*phigh = 0;
v = (uint64_t)a0 * (uint64_t)b1;
add128(plow, phigh, v << 32, v >> 32);
v = (uint64_t)a1 * (uint64_t)b0;
add128(plow, phigh, v << 32, v >> 32);
v = (uint64_t)a1 * (uint64_t)b1;
*phigh += v;
}
/* Unsigned 64x64 -> 128 multiplication */
void mulu64(uint64_t *phigh, uint64_t *plow, uint64_t a, uint64_t b)
void mulu64 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)
{
#if defined(__x86_64__)
__asm__ ("mul %0\n\t"
: "=d" (*phigh), "=a" (*plow)
: "a" (a), "0" (b)
);
: "a" (a), "0" (b));
#else
uint64_t ph, pm1, pm2, pl;
pl = (uint64_t)((uint32_t)a) * (uint64_t)((uint32_t)b);
pm1 = (a >> 32) * (uint32_t)b;
pm2 = (uint32_t)a * (b >> 32);
ph = (a >> 32) * (b >> 32);
ph += pm1 >> 32;
ph += pm2 >> 32;
pm1 = (uint64_t)((uint32_t)pm1) + (uint64_t)((uint32_t)pm2) + (pl >> 32);
*phigh = ph + (pm1 >> 32);
*plow = (pm1 << 32) + (uint32_t)pl;
mul64(plow, phigh, a, b);
#endif
#if defined(DEBUG_MULDIV)
printf("mulu64: 0x%016llx * 0x%016llx = 0x%016llx%016llx\n",
a, b, *phigh, *plow);
#endif
}
/* Signed 64x64 -> 128 multiplication */
void muls64 (uint64_t *plow, uint64_t *phigh, int64_t a, int64_t b)
{
#if defined(__x86_64__)
__asm__ ("imul %0\n\t"
: "=d" (*phigh), "=a" (*plow)
: "a" (a), "0" (b));
#else
int sa, sb;
sa = (a < 0);
if (sa)
a = -a;
sb = (b < 0);
if (sb)
b = -b;
mul64(plow, phigh, a, b);
if (sa ^ sb) {
neg128(plow, phigh);
}
#endif
#if defined(DEBUG_MULDIV)
printf("muls64: 0x%016llx * 0x%016llx = 0x%016llx%016llx\n",
a, b, *phigh, *plow);
#endif
}