* Volume 2A: Instruction Set Reference, A-M
*/
-#ifdef ARCH_HAVE_SSE
+int crc32c_intel_available = 0;
+
+#ifdef ARCH_HAVE_SSE4_2
#if BITS_PER_LONG == 64
#define REX_PRE "0x48, "
#define SCALE_F 4
#endif
-uint32_t crc32c_intel_le_hw_byte(uint32_t crc, unsigned char const *data,
- unsigned long length)
+static int crc32c_probed;
+
+static uint32_t crc32c_intel_le_hw_byte(uint32_t crc, unsigned char const *data,
+ unsigned long length)
{
while (length--) {
__asm__ __volatile__(
return crc;
}
-static void do_cpuid(unsigned int *eax, unsigned int *ebx, unsigned int *ecx,
- unsigned int *edx)
+void crc32c_intel_probe(void)
{
- int id = *eax;
+ if (!crc32c_probed) {
+ unsigned int eax, ebx, ecx = 0, edx;
- asm("movl %4, %%eax;"
- "cpuid;"
- "movl %%eax, %0;"
- "movl %%ebx, %1;"
- "movl %%ecx, %2;"
- "movl %%edx, %3;"
- : "=r" (*eax), "=r" (*ebx), "=r" (*ecx), "=r" (*edx)
- : "r" (id)
- : "eax", "ebx", "ecx", "edx");
-}
+ eax = 1;
-int crc32c_intel_works(void)
-{
- unsigned int eax, ebx, ecx, edx;
-
- eax = 1;
-
- do_cpuid(&eax, &ebx, &ecx, &edx);
- return (ecx & (1 << 20)) != 0;
+ do_cpuid(&eax, &ebx, &ecx, &edx);
+ crc32c_intel_available = (ecx & (1 << 20)) != 0;
+ crc32c_probed = 1;
+ }
}
#endif /* ARCH_HAVE_SSE */