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/**
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0.
*/
/*
* MSVC wants us to use the non-portable _dupenv_s instead; since we need
* to remain portable, tell MSVC to suppress this warning.
*/
#define _CRT_SECURE_NO_WARNINGS
#include <aws/common/cpuid.h>
#include <stdlib.h>
extern void aws_run_cpuid(uint32_t eax, uint32_t ecx, uint32_t *abcd);
typedef bool(has_feature_fn)(void);
static bool s_has_clmul(void) {
uint32_t abcd[4];
uint32_t clmul_mask = 0x00000002;
aws_run_cpuid(1, 0, abcd);
if ((abcd[2] & clmul_mask) != clmul_mask)
return false;
return true;
}
static bool s_has_sse41(void) {
uint32_t abcd[4];
uint32_t sse41_mask = 0x00080000;
aws_run_cpuid(1, 0, abcd);
if ((abcd[2] & sse41_mask) != sse41_mask)
return false;
return true;
}
static bool s_has_sse42(void) {
uint32_t abcd[4];
uint32_t sse42_mask = 0x00100000;
aws_run_cpuid(1, 0, abcd);
if ((abcd[2] & sse42_mask) != sse42_mask)
return false;
return true;
}
static bool s_has_avx2(void) {
uint32_t abcd[4];
uint32_t avx2_bmi12_mask = (1 << 5) | (1 << 3) | (1 << 8);
/* CPUID.(EAX=01H, ECX=0H):ECX.FMA[bit 12]==1 &&
CPUID.(EAX=01H, ECX=0H):ECX.MOVBE[bit 22]==1 &&
CPUID.(EAX=01H, ECX=0H):ECX.OSXSAVE[bit 27]==1 */
aws_run_cpuid(7, 0, abcd);
if ((abcd[1] & avx2_bmi12_mask) != avx2_bmi12_mask)
return false;
return true;
}
has_feature_fn *s_check_cpu_feature[AWS_CPU_FEATURE_COUNT] = {
[AWS_CPU_FEATURE_CLMUL] = s_has_clmul,
[AWS_CPU_FEATURE_SSE_4_1] = s_has_sse41,
[AWS_CPU_FEATURE_SSE_4_2] = s_has_sse42,
[AWS_CPU_FEATURE_AVX2] = s_has_avx2,
};
bool aws_cpu_has_feature(enum aws_cpu_feature_name feature_name) {
if (s_check_cpu_feature[feature_name])
return s_check_cpu_feature[feature_name]();
return false;
}
#define CPUID_AVAILABLE 0
#define CPUID_UNAVAILABLE 1
static int cpuid_state = 2;
bool aws_common_private_has_avx2(void) {
if (AWS_LIKELY(cpuid_state == 0)) {
return true;
}
if (AWS_LIKELY(cpuid_state == 1)) {
return false;
}
/* Provide a hook for testing fallbacks and benchmarking */
const char *env_avx2_enabled = getenv("AWS_COMMON_AVX2");
if (env_avx2_enabled) {
int is_enabled = atoi(env_avx2_enabled);
cpuid_state = !is_enabled;
return is_enabled;
}
bool available = aws_cpu_has_feature(AWS_CPU_FEATURE_AVX2);
cpuid_state = available ? CPUID_AVAILABLE : CPUID_UNAVAILABLE;
return available;
}
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