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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* compile-time and runtime tests for whether to use SSE instructions */
#include "SSE.h"
#ifdef HAVE_CPUID_H
// cpuid.h is available on gcc 4.3 and higher on i386 and x86_64
#include <cpuid.h>
#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_AMD64))
// MSVC 2005 or newer on x86-32 or x86-64
#include <intrin.h>
#endif
namespace {
// SSE.h has parallel #ifs which declare MOZILLA_SSE_HAVE_CPUID_DETECTION.
// We can't declare these functions in the header file, however, because
// <intrin.h> conflicts with <windows.h> on MSVC 2005, and some files want to
// include both SSE.h and <windows.h>.
#ifdef HAVE_CPUID_H
enum CPUIDRegister { eax = 0, ebx = 1, ecx = 2, edx = 3 };
static bool
has_cpuid_bits(unsigned int level, CPUIDRegister reg, unsigned int bits)
{
unsigned int regs[4];
unsigned int eax, ebx, ecx, edx;
unsigned max = __get_cpuid_max(0, NULL);
if (level > max)
return false;
__cpuid_count(level, 0, eax, ebx, ecx, edx);
regs[0] = eax;
regs[1] = ebx;
regs[2] = ecx;
regs[3] = edx;
return (regs[reg] & bits) == bits;
}
#if !defined(MOZILLA_PRESUME_AVX)
static uint64_t xgetbv(uint32_t xcr) {
uint32_t eax, edx;
__asm__ ( ".byte 0x0f, 0x01, 0xd0" : "=a"(eax), "=d"(edx) : "c"(xcr));
return (uint64_t)(edx) << 32 | eax;
}
#endif
#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_AMD64))
enum CPUIDRegister { eax = 0, ebx = 1, ecx = 2, edx = 3 };
static bool
has_cpuid_bits(unsigned int level, CPUIDRegister reg, unsigned int bits)
{
// Check that the level in question is supported.
int regs[4];
__cpuid(regs, level & 0x80000000u);
if (unsigned(regs[0]) < level)
return false;
// "The __cpuid intrinsic clears the ECX register before calling the cpuid instruction."
__cpuid(regs, level);
return (unsigned(regs[reg]) & bits) == bits;
}
#if !defined(MOZILLA_PRESUME_AVX)
static uint64_t xgetbv(uint32_t xcr) { return _xgetbv(xcr); }
#endif
#elif (defined(__GNUC__) || defined(__SUNPRO_CC)) && (defined(__i386) || defined(__x86_64__))
enum CPUIDRegister { eax = 0, ebx = 1, ecx = 2, edx = 3 };
#ifdef __i386
static void
moz_cpuid(int CPUInfo[4], int InfoType)
{
asm (
"xchg %esi, %ebx\n"
"xor %ecx, %ecx\n" // ecx is the sub-leaf (we only ever need 0)
"cpuid\n"
"movl %eax, (%edi)\n"
"movl %ebx, 4(%edi)\n"
"movl %ecx, 8(%edi)\n"
"movl %edx, 12(%edi)\n"
"xchg %esi, %ebx\n"
:
: "a"(InfoType), // %eax
"D"(CPUInfo) // %edi
: "%ecx", "%edx", "%esi"
);
}
#else
static void
moz_cpuid(int CPUInfo[4], int InfoType)
{
asm (
"xchg %rsi, %rbx\n"
"xor %ecx, %ecx\n" // ecx is the sub-leaf (we only ever need 0)
"cpuid\n"
"movl %eax, (%rdi)\n"
"movl %ebx, 4(%rdi)\n"
"movl %ecx, 8(%rdi)\n"
"movl %edx, 12(%rdi)\n"
"xchg %rsi, %rbx\n"
:
: "a"(InfoType), // %eax
"D"(CPUInfo) // %rdi
: "%ecx", "%edx", "%rsi"
);
}
#endif
static bool
has_cpuid_bits(unsigned int level, CPUIDRegister reg, unsigned int bits)
{
// Check that the level in question is supported.
volatile int regs[4];
moz_cpuid((int *)regs, level & 0x80000000u);
if (unsigned(regs[0]) < level)
return false;
moz_cpuid((int *)regs, level);
return (unsigned(regs[reg]) & bits) == bits;
}
#endif // end CPUID declarations
} // namespace
namespace mozilla {
namespace sse_private {
#if defined(MOZILLA_SSE_HAVE_CPUID_DETECTION)
#if !defined(MOZILLA_PRESUME_MMX)
bool mmx_enabled = has_cpuid_bits(1u, edx, (1u<<23));
#endif
#if !defined(MOZILLA_PRESUME_SSE)
bool sse_enabled = has_cpuid_bits(1u, edx, (1u<<25));
#endif
#if !defined(MOZILLA_PRESUME_SSE2)
bool sse2_enabled = has_cpuid_bits(1u, edx, (1u<<26));
#endif
#if !defined(MOZILLA_PRESUME_SSE3)
bool sse3_enabled = has_cpuid_bits(1u, ecx, (1u<<0));
#endif
#if !defined(MOZILLA_PRESUME_SSSE3)
bool ssse3_enabled = has_cpuid_bits(1u, ecx, (1u<<9));
#endif
#if !defined(MOZILLA_PRESUME_SSE4A)
bool sse4a_enabled = has_cpuid_bits(0x80000001u, ecx, (1u<<6));
#endif
#if !defined(MOZILLA_PRESUME_SSE4_1)
bool sse4_1_enabled = has_cpuid_bits(1u, ecx, (1u<<19));
#endif
#if !defined(MOZILLA_PRESUME_SSE4_2)
bool sse4_2_enabled = has_cpuid_bits(1u, ecx, (1u<<20));
#endif
#if !defined(MOZILLA_PRESUME_AVX) || !defined(MOZILLA_PRESUME_AVX2)
static bool has_avx()
{
#if defined(MOZILLA_PRESUME_AVX)
return true;
#else
const unsigned AVX = 1u << 28;
const unsigned OSXSAVE = 1u << 27;
const unsigned XSAVE = 1u << 26;
const unsigned XMM_STATE = 1u << 1;
const unsigned YMM_STATE = 1u << 2;
const unsigned AVX_STATE = XMM_STATE | YMM_STATE;
return has_cpuid_bits(1u, ecx, AVX | OSXSAVE | XSAVE) &&
// ensure the OS supports XSAVE of YMM registers
(xgetbv(0) & AVX_STATE) == AVX_STATE;
#endif // MOZILLA_PRESUME_AVX
}
#endif // !MOZILLA_PRESUME_AVX || !MOZILLA_PRESUME_AVX2
#if !defined(MOZILLA_PRESUME_AVX)
bool avx_enabled = has_avx();
#endif
#if !defined(MOZILLA_PRESUME_AVX2)
bool avx2_enabled = has_avx() && has_cpuid_bits(7u, ebx, (1u<<5));
#endif
#endif
} // namespace sse_private
} // namespace mozilla
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