1 // Copyright 2018 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4
5 // +build 386 amd64 amd64p32
6 // +build gccgo
7
8 #include <cpuid.h>
9 #include <stdint.h>
10
11 // Need to wrap __get_cpuid_count because it's declared as static.
12 int
13 gccgoGetCpuidCount(uint32_t leaf, uint32_t subleaf,
14 uint32_t *eax, uint32_t *ebx,
15 uint32_t *ecx, uint32_t *edx)
16 {
17 return __get_cpuid_count(leaf, subleaf, eax, ebx, ecx, edx);
18 }
19
20 // xgetbv reads the contents of an XCR (Extended Control Register)
21 // specified in the ECX register into registers EDX:EAX.
22 // Currently, the only supported value for XCR is 0.
23 //
24 // TODO: Replace with a better alternative:
25 //
26 // #include <xsaveintrin.h>
27 //
28 // #pragma GCC target("xsave")
29 //
30 // void gccgoXgetbv(uint32_t *eax, uint32_t *edx) {
31 // unsigned long long x = _xgetbv(0);
32 // *eax = x & 0xffffffff;
33 // *edx = (x >> 32) & 0xffffffff;
34 // }
35 //
36 // Note that _xgetbv is defined starting with GCC 8.
37 void
38 gccgoXgetbv(uint32_t *eax, uint32_t *edx)
39 {
40 __asm(" xorl %%ecx, %%ecx\n"
41 " xgetbv"
42 : "=a"(*eax), "=d"(*edx));
43 }
44
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