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#include <string.h>
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <stdint.h>
#include <math.h>
#if defined(__x86_64__)
#error Nope!
#else
__attribute__((naked)) uint64_t _idiv_(uint32_t a, uint32_t b)
{
asm volatile (
"xor %%eax, %%eax\n"
"mov 4(%%esp), %%edx\n"
"mov 8(%%esp), %%ecx\n"
"shrd $0x10, %%edx, %%eax\n"
"sar $0x10, %%edx\n"
"idiv %%ecx\n"
"ret"
:::);
}
#endif
int main(int argc, const char** argv)
{
uint32_t tests[][2] = {
{0x000002d0, 0x00000500},
{0xfffffa5d, 0x000186a0},
{0x00001701, 0x000186a0},
{0xffff9a19, 0x000186a0},
{0xffffe7f3, 0x000186a0},
{0x00015840, 0x000186a0},
{0xff451330, 0x000186a0},
{0xffff626a, 0x000186a0},
{0x00009120, 0x000186a0},
};
int n = sizeof(tests)/sizeof(tests[0]);
uint64_t res;
for(int i=0; i<n; ++i) {
printf("SDHLD/SAR/IDIV 0x%x 0x%x ", tests[i][0], tests[i][1]);
res = _idiv_(tests[i][0], tests[i][1]);
uint32_t divi = res & 0xffffffffLL;
uint32_t modo = res >> 32;
printf("=> 0x%x / 0x%x (%lld/%d => %d + %d)\n", modo, divi, ((int64_t)tests[i][0])<<16, tests[i][1], divi, modo);
}
printf("\nDone\n");
}
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