1/*
2 * Copyright 2010-2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License").
5 * You may not use this file except in compliance with the License.
6 * A copy of the License is located at
7 *
8 * http://aws.amazon.com/apache2.0
9 *
10 * or in the "license" file accompanying this file. This file is distributed
11 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
12 * express or implied. See the License for the specific language governing
13 * permissions and limitations under the License.
14 */
15
16#include <aws/checksums/private/cpuid.h>
17#include <stdint.h>
18
19#if defined(__x86_64__) && !(defined(__GNUC__) && defined(DEBUG_BUILD))
20
21static int32_t s_cpuid_output = 0;
22static int s_cpuid_ran = 0;
23
24int aws_checksums_do_cpu_id(int32_t *cpuid) {
25
26 if (!s_cpuid_ran) {
27
28 asm volatile("XOR %%rax, %%rax # zero the eax register\n"
29 "INC %%eax # eax=1 for processor feature bits\n"
30 "CPUID #get feature bits\n"
31 : "=c"(s_cpuid_output)
32 : // none
33 : "%rax", "%rbx", "%rdx", "cc");
34 s_cpuid_ran = 1;
35 }
36
37 *cpuid = s_cpuid_output;
38 return 1;
39}
40
41#endif /* defined(__x86_64__) && !(defined(__GNUC__) && defined(DEBUG_BUILD)) */
42