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#include <stdint.h>
#include <stdio.h>
typedef struct {
uint32_t eax, ebx, ecx, edx;
} cpuid_t;
// in: eax is the cpuid leaf number
static inline cpuid_t cpuid(uint32_t eax) {
cpuid_t r;
asm volatile("cpuid"
: "=a"(r.eax), "=b"(r.ebx), "=c"(r.ecx), "=d"(r.edx)
: "a"(eax), "c"(0));
return r;
};
// in: eax is the cpuid leaf number
// in: ecx is the cpuid sub-leaf number
static inline cpuid_t cpuid_subleaf(uint32_t eax, uint32_t ecx) {
cpuid_t r;
asm volatile("cpuid"
: "=a"(r.eax), "=b"(r.ebx), "=c"(r.ecx), "=d"(r.edx)
: "a"(eax), "c"(ecx));
return r;
};
int main() {
cpuid_t r;
uint32_t leafs = 1;
for (uint32_t l = 0; l < leafs; ++l) {
r = cpuid(l);
if (l == 0) {
// leaf 0 returns the highest available cpuid leaf in eax.
leafs = r.eax;
// ebx, edx, ecx contain the vendor string
// clang-format off
printf("vendor: %c%c%c%c%c%c%c%c%c%c%c%c\n",
(r.ebx & 0xFF), (r.ebx >> 8) & 0xFF, (r.ebx >> 16) & 0xFF, (r.ebx >> 24) & 0xFF,
(r.edx & 0xFF), (r.edx >> 8) & 0xFF, (r.edx >> 16) & 0xFF, (r.edx >> 24) & 0xFF,
(r.ecx & 0xFF), (r.ecx >> 8) & 0xFF, (r.ecx >> 16) & 0xFF, (r.ecx >> 24) & 0xFF);
// clang-format on
}
printf("[0x%08x] eax=%08x ebx=%08x ecx=%08x edx=%08x\n", l, r.eax, r.ebx, r.ecx, r.edx);
}
}
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