mozglue/misc/SSE.cpp

   1 /* vim: set shiftwidth=4 tabstop=8 autoindent cindent expandtab: */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 /* compile-time and runtime tests for whether to use SSE instructions */
   7
   8 #include "SSE.h"
   9
  10 #ifdef HAVE_CPUID_H
  11 // cpuid.h is available on gcc 4.3 and higher on i386 and x86_64
  12 #  include <cpuid.h>
  13 #elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_AMD64))
  14 // MSVC 2005 or newer on x86-32 or x86-64
  15 #  include <intrin.h>
  16 #endif
  17
  18 namespace {
  19
  20 // SSE.h has parallel #ifs which declare MOZILLA_SSE_HAVE_CPUID_DETECTION.
  21 // We can't declare these functions in the header file, however, because
  22 // <intrin.h> conflicts with <windows.h> on MSVC 2005, and some files want to
  23 // include both SSE.h and <windows.h>.
  24
  25 #ifdef HAVE_CPUID_H
  26
  27 enum CPUIDRegister { eax = 0, ebx = 1, ecx = 2, edx = 3 };
  28
  29 static bool has_cpuid_bits(unsigned int level, CPUIDRegister reg,
  30                            unsigned int bits) {
  31   unsigned int regs[4];
  32   unsigned int eax, ebx, ecx, edx;
  33   unsigned max = __get_cpuid_max(level & 0x80000000u, nullptr);
  34   if (level > max) return false;
  35   __cpuid_count(level, 0, eax, ebx, ecx, edx);
  36   regs[0] = eax;
  37   regs[1] = ebx;
  38   regs[2] = ecx;
  39   regs[3] = edx;
  40   return (regs[reg] & bits) == bits;
  41 }
  42
  43 #elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_AMD64))
  44
  45 enum CPUIDRegister { eax = 0, ebx = 1, ecx = 2, edx = 3 };
  46
  47 static bool has_cpuid_bits(unsigned int level, CPUIDRegister reg,
  48                            unsigned int bits) {
  49   // Check that the level in question is supported.
  50   int regs[4];
  51   __cpuid(regs, level & 0x80000000u);
  52   if (unsigned(regs[0]) < level) return false;
  53
  54   // "The __cpuid intrinsic clears the ECX register before calling the cpuid
  55   // instruction."
  56   __cpuid(regs, level);
  57   return (unsigned(regs[reg]) & bits) == bits;
  58 }
  59
  60 #elif (defined(__GNUC__) || defined(__SUNPRO_CC)) && \
  61     (defined(__i386) || defined(__x86_64__))
  62
  63 enum CPUIDRegister { eax = 0, ebx = 1, ecx = 2, edx = 3 };
  64
  65 #  ifdef __i386
  66 static void moz_cpuid(int CPUInfo[4], int InfoType) {
  67   asm("xchg %esi, %ebx\n"
  68       "xor %ecx, %ecx\n"  // ecx is the sub-leaf (we only ever need 0)
  69       "cpuid\n"
  70       "movl %eax, (%edi)\n"
  71       "movl %ebx, 4(%edi)\n"
  72       "movl %ecx, 8(%edi)\n"
  73       "movl %edx, 12(%edi)\n"
  74       "xchg %esi, %ebx\n"
  75       :
  76       : "a"(InfoType),  // %eax
  77         "D"(CPUInfo)    // %edi
  78       : "%ecx", "%edx", "%esi");
  79 }
  80 #  else
  81 static void moz_cpuid(int CPUInfo[4], int InfoType) {
  82   asm("xchg %rsi, %rbx\n"
  83       "xor %ecx, %ecx\n"  // ecx is the sub-leaf (we only ever need 0)
  84       "cpuid\n"
  85       "movl %eax, (%rdi)\n"
  86       "movl %ebx, 4(%rdi)\n"
  87       "movl %ecx, 8(%rdi)\n"
  88       "movl %edx, 12(%rdi)\n"
  89       "xchg %rsi, %rbx\n"
  90       :
  91       : "a"(InfoType),  // %eax
  92         "D"(CPUInfo)    // %rdi
  93       : "%ecx", "%edx", "%rsi");
  94 }
  95 #  endif
  96
  97 static bool has_cpuid_bits(unsigned int level, CPUIDRegister reg,
  98                            unsigned int bits) {
  99   // Check that the level in question is supported.
 100   volatile int regs[4];
 101   moz_cpuid((int*)regs, level & 0x80000000u);
 102   if (unsigned(regs[0]) < level) return false;
 103
 104   moz_cpuid((int*)regs, level);
 105   return (unsigned(regs[reg]) & bits) == bits;
 106 }
 107
 108 #endif  // end CPUID declarations
 109
 110 }  // namespace
 111
 112 namespace mozilla {
 113
 114 namespace sse_private {
 115
 116 #if defined(MOZILLA_SSE_HAVE_CPUID_DETECTION)
 117
 118 #  if !defined(MOZILLA_PRESUME_MMX)
 119 bool mmx_enabled = has_cpuid_bits(1u, edx, (1u << 23));
 120 #  endif
 121
 122 #  if !defined(MOZILLA_PRESUME_SSE)
 123 bool sse_enabled = has_cpuid_bits(1u, edx, (1u << 25));
 124 #  endif
 125
 126 #  if !defined(MOZILLA_PRESUME_SSE2)
 127 bool sse2_enabled = has_cpuid_bits(1u, edx, (1u << 26));
 128 #  endif
 129
 130 #  if !defined(MOZILLA_PRESUME_SSE3)
 131 bool sse3_enabled = has_cpuid_bits(1u, ecx, (1u << 0));
 132 #  endif
 133
 134 #  if !defined(MOZILLA_PRESUME_SSSE3)
 135 bool ssse3_enabled = has_cpuid_bits(1u, ecx, (1u << 9));
 136 #  endif
 137
 138 #  if !defined(MOZILLA_PRESUME_SSE4A)
 139 bool sse4a_enabled = has_cpuid_bits(0x80000001u, ecx, (1u << 6));
 140 #  endif
 141
 142 #  if !defined(MOZILLA_PRESUME_SSE4_1)
 143 bool sse4_1_enabled = has_cpuid_bits(1u, ecx, (1u << 19));
 144 #  endif
 145
 146 #  if !defined(MOZILLA_PRESUME_SSE4_2)
 147 bool sse4_2_enabled = has_cpuid_bits(1u, ecx, (1u << 20));
 148 #  endif
 149
 150 #  if !defined(MOZILLA_PRESUME_AVX) || !defined(MOZILLA_PRESUME_AVX2)
 151 static bool has_avx() {
 152 #    if defined(MOZILLA_PRESUME_AVX)
 153   return true;
 154 #    else
 155   const unsigned AVX = 1u << 28;
 156   const unsigned OSXSAVE = 1u << 27;
 157   const unsigned XSAVE = 1u << 26;
 158
 159   const unsigned XMM_STATE = 1u << 1;
 160   const unsigned YMM_STATE = 1u << 2;
 161   const unsigned AVX_STATE = XMM_STATE | YMM_STATE;
 162
 163   return has_cpuid_bits(1u, ecx, AVX | OSXSAVE | XSAVE) &&
 164          // ensure the OS supports XSAVE of YMM registers
 165          (xgetbv(0) & AVX_STATE) == AVX_STATE;
 166 #    endif  // MOZILLA_PRESUME_AVX
 167 }
 168 #  endif  // !MOZILLA_PRESUME_AVX || !MOZILLA_PRESUME_AVX2
 169
 170 #  if !defined(MOZILLA_PRESUME_AVX)
 171 bool avx_enabled = has_avx();
 172 #  endif
 173
 174 #  if !defined(MOZILLA_PRESUME_AVX2)
 175 bool avx2_enabled = has_avx() && has_cpuid_bits(7u, ebx, (1u << 5));
 176 #  endif
 177
 178 #  if !defined(MOZILLA_PRESUME_AES)
 179 bool aes_enabled = has_cpuid_bits(1u, ecx, (1u << 25));
 180 #  endif
 181
 182 bool has_constant_tsc = has_cpuid_bits(0x80000007u, edx, (1u << 8));
 183
 184 #endif
 185
 186 }  // namespace sse_private
 187
 188 #ifdef HAVE_CPUID_H
 189
 190 uint64_t xgetbv(uint32_t xcr) {
 191   uint32_t eax, edx;
 192   __asm__(".byte 0x0f, 0x01, 0xd0" : "=a"(eax), "=d"(edx) : "c"(xcr));
 193   return (uint64_t)(edx) << 32 | eax;
 194 }
 195
 196 #endif
 197
 198 }  // namespace mozilla