+++ /dev/null
-/*
- * x86_cpu_features.c - feature detection for x86 processors
- *
- * Copyright 2022 Eric Biggers
- *
- * Permission is hereby granted, free of charge, to any person
- * obtaining a copy of this software and associated documentation
- * files (the "Software"), to deal in the Software without
- * restriction, including without limitation the rights to use,
- * copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following
- * conditions:
- *
- * The above copyright notice and this permission notice shall be
- * included in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
- * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
- * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
- * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
- * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
- * OTHER DEALINGS IN THE SOFTWARE.
- */
-
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
-
-#include "wimlib/x86_cpu_features.h"
-
-#if defined(__i386__) || defined(__x86_64__)
-
-#define DEBUG 0
-
-#if DEBUG
-# include <stdio.h>
-#endif
-
-u32 _x86_cpu_features = 0;
-
-/* With old GCC versions we have to manually save and restore the x86_32 PIC
- * register (ebx). See: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47602 */
-#if defined(__i386__) && defined(__PIC__)
-# define EBX_CONSTRAINT "=r"
-#else
-# define EBX_CONSTRAINT "=b"
-#endif
-
-/* Execute the CPUID instruction. */
-static inline void
-cpuid(u32 leaf, u32 subleaf, u32 *a, u32 *b, u32 *c, u32 *d)
-{
- __asm__(".ifnc %%ebx, %1; mov %%ebx, %1; .endif\n"
- "cpuid \n"
- ".ifnc %%ebx, %1; xchg %%ebx, %1; .endif\n"
- : "=a" (*a), EBX_CONSTRAINT (*b), "=c" (*c), "=d" (*d)
- : "a" (leaf), "c" (subleaf));
-}
-
-/* Read an extended control register. */
-static inline u64
-read_xcr(u32 index)
-{
- u32 edx, eax;
-
- /* Execute the "xgetbv" instruction. Old versions of binutils do not
- * recognize this instruction, so list the raw bytes instead. */
- __asm__ (".byte 0x0f, 0x01, 0xd0" : "=d" (edx), "=a" (eax) : "c" (index));
-
- return ((u64)edx << 32) | eax;
-}
-
-#define IS_SET(reg, bit) ((reg) & ((u32)1 << (bit)))
-
-/* Initialize _x86_cpu_features with bits for interesting processor features. */
-void
-x86_setup_cpu_features(void)
-{
- u32 features = 0;
- u32 dummy1, dummy2, dummy3, dummy4;
- u32 max_function;
- u32 features_1, features_2, features_3, features_4;
- bool os_saves_ymm_regs = false;
-
- /* Get maximum supported function */
- cpuid(0, 0, &max_function, &dummy2, &dummy3, &dummy4);
- if (max_function < 1)
- goto out;
-
- /* Standard feature flags */
- cpuid(1, 0, &dummy1, &dummy2, &features_2, &features_1);
-
- if (IS_SET(features_1, 25))
- features |= X86_CPU_FEATURE_SSE;
-
- if (IS_SET(features_1, 26))
- features |= X86_CPU_FEATURE_SSE2;
-
- if (IS_SET(features_2, 0))
- features |= X86_CPU_FEATURE_SSE3;
-
- if (IS_SET(features_2, 9))
- features |= X86_CPU_FEATURE_SSSE3;
-
- if (IS_SET(features_2, 19))
- features |= X86_CPU_FEATURE_SSE4_1;
-
- if (IS_SET(features_2, 20))
- features |= X86_CPU_FEATURE_SSE4_2;
-
- if (IS_SET(features_2, 27)) /* OSXSAVE set? */
- if ((read_xcr(0) & 0x6) == 0x6)
- os_saves_ymm_regs = true;
-
- if (os_saves_ymm_regs && IS_SET(features_2, 28))
- features |= X86_CPU_FEATURE_AVX;
-
- if (max_function < 7)
- goto out;
-
- /* Extended feature flags */
- cpuid(7, 0, &dummy1, &features_3, &features_4, &dummy4);
-
- if (IS_SET(features_3, 3))
- features |= X86_CPU_FEATURE_BMI;
-
- if (os_saves_ymm_regs && IS_SET(features_3, 5))
- features |= X86_CPU_FEATURE_AVX2;
-
- if (IS_SET(features_3, 8))
- features |= X86_CPU_FEATURE_BMI2;
-
-out:
-
-#if DEBUG
- printf("Detected x86 CPU features: ");
- if (features & X86_CPU_FEATURE_SSE)
- printf("SSE ");
- if (features & X86_CPU_FEATURE_SSE2)
- printf("SSE2 ");
- if (features & X86_CPU_FEATURE_SSE3)
- printf("SSE3 ");
- if (features & X86_CPU_FEATURE_SSSE3)
- printf("SSSE3 ");
- if (features & X86_CPU_FEATURE_SSE4_1)
- printf("SSE4.1 ");
- if (features & X86_CPU_FEATURE_SSE4_2)
- printf("SSE4.2 ");
- if (features & X86_CPU_FEATURE_BMI)
- printf("BMI ");
- if (features & X86_CPU_FEATURE_AVX)
- printf("AVX ");
- if (features & X86_CPU_FEATURE_BMI2)
- printf("BMI2 ");
- if (features & X86_CPU_FEATURE_AVX2)
- printf("AVX2 ");
- printf("\n");
-#endif /* DEBUG */
-
- _x86_cpu_features = features | X86_CPU_FEATURES_KNOWN;
-}
-
-#endif /* __i386__ || __x86_64__ */
git://wimlib.net / wimlib / blobdiff