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#include <cassert>
#include <cinttypes>
#include <cstdint>
#include <cstdio>
struct alignas(16) float80_raw {
uint8_t data[10];
};
int main() {
float80_raw st[8];
uint16_t env[14];
union alignas(16) {
uint16_t i16[256];
uint32_t i32[128];
uint64_t i64[64];
} fxsave;
asm volatile(
"finit\n\t"
"int3\n\t"
#if defined(__x86_64__)
"fxsave64 %2\n\t"
#else
"fxsave %2\n\t"
#endif
"fnstenv %1\n\t"
"fnclex\n\t"
"fstpt 0x00(%0)\n\t"
"fstpt 0x10(%0)\n\t"
"fstpt 0x20(%0)\n\t"
"fstpt 0x30(%0)\n\t"
"fstpt 0x40(%0)\n\t"
"fstpt 0x50(%0)\n\t"
"fstpt 0x60(%0)\n\t"
"fstpt 0x70(%0)\n\t"
:
: "a"(st), "m"(env), "m"(fxsave)
: "st"
);
assert(env[0] == fxsave.i16[0]);
assert(env[2] == fxsave.i16[1]);
printf("fctrl = 0x%04" PRIx16 "\n", env[0]);
printf("fstat = 0x%04" PRIx16 "\n", env[2]);
printf("ftag = 0x%04" PRIx16 "\n", env[4]);
printf("fop = 0x%04" PRIx16 "\n", fxsave.i16[3]);
#if defined(__x86_64__)
printf("fip = 0x%016" PRIx64 "\n", fxsave.i64[1]);
printf("fdp = 0x%016" PRIx64 "\n", fxsave.i64[2]);
#else
printf("fip = 0x%08" PRIx32 "\n", fxsave.i32[2]);
printf("fcs = 0x%04" PRIx16 "\n", fxsave.i16[6]);
printf("fdp = 0x%08" PRIx32 "\n", fxsave.i32[4]);
printf("fds = 0x%04" PRIx16 "\n", fxsave.i16[10]);
#endif
printf("mxcsr = 0x%08" PRIx32 "\n", fxsave.i32[6]);
printf("mxcsr_mask = 0x%08" PRIx32 "\n", fxsave.i32[7]);
for (int i = 0; i < 8; ++i) {
printf("st%d = { ", i);
for (int j = 0; j < sizeof(st->data); ++j)
printf("0x%02" PRIx8 " ", st[i].data[j]);
printf("}\n");
}
return 0;
}
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