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#include <cstdint>
struct alignas(16) float80_raw {
uint64_t mantissa;
uint16_t sign_exp;
};
int main() {
float80_raw st[] = {
{0x8000000000000000, 0x4000}, // +2.0
{0x3f00000000000000, 0x0000}, // 1.654785e-4932 (denormal)
{0x0000000000000000, 0x0000}, // +0
{0x0000000000000000, 0x8000}, // -0
{0x8000000000000000, 0x7fff}, // +inf
{0x8000000000000000, 0xffff}, // -inf
{0xc000000000000000, 0xffff}, // nan
// st7 will be freed to test tag word better
{0x0000000000000000, 0x0000}, // +0
};
// unmask divide-by-zero exception
uint16_t cw = 0x037b;
// used as single-precision float
uint32_t zero = 0;
asm volatile(
"finit\n\t"
"fldcw %1\n\t"
// load on stack in reverse order to make the result easier to read
"fldt 0x70(%0)\n\t"
"fldt 0x60(%0)\n\t"
"fldt 0x50(%0)\n\t"
"fldt 0x40(%0)\n\t"
"fldt 0x30(%0)\n\t"
"fldt 0x20(%0)\n\t"
"fldt 0x10(%0)\n\t"
"fldt 0x00(%0)\n\t"
// free st7
"ffree %%st(7)\n\t"
// this should trigger a divide-by-zero
"fdivs (%2)\n\t"
"int3\n\t"
:
: "a"(st), "m"(cw), "b"(&zero)
: "st"
);
return 0;
}
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