detect cpu feature for all x64 and x86 platforms (no longer windows only).

base/cpu.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.

[fbarchard, 2011/02/15 01:42:56]

(C) 2011

 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/cpu.h"
+
+#if defined(ARCH_CPU_X86_FAMILY)
+#if defined(_MSC_VER)
 #include <intrin.h>
-#include <string>
+#endif
+#endif
+
+#include <string.h>
 
 namespace base {
 
 CPU::CPU()
   : type_(0),
     family_(0),
     model_(0),
     stepping_(0),
     ext_model_(0),
     ext_family_(0),
+    has_sse2_(false),
     cpu_vendor_("unknown") {
   Initialize();
 }
 
+#if defined(ARCH_CPU_X86_FAMILY)
+static void cpuid(int info[4], int info_type) {
+#if defined( _MSC_VER)
+  __cpuid(info, info_type);
+#else
+  asm volatile (
+      "cpuid            \n\t"
+      "movl %%ebx, %1   \n\t"
+      : "=a"(info[0]), "=r"(info[1]), "=c"(info[2]), "=d"(info[3])
+      : "a"(info_type)
+  );
+#endif
+}
+#endif

[fbarchard, 2011/02/15 01:42:56]

Your ebx usage seems -m32 -fpic unsafe?
I tried it, and it segfaulted
fbarchard@muni:~/icpuid$ g++ -fomit-frame-pointer -O3 -fpic -m32 -DGAS_ASM
-DCPU_DEBUG icpuid.cpp -o icpuid
fbarchard@muni:~/icpuid$ ./icpuid
Segmentation fault
fbarchard@muni:~/icpuid$ g++ -fomit-frame-pointer -O3 -m32 -DGAS_ASM -DCPU_DEBUG
icpuid.cpp -o icpuid
fbarchard@muni:~/icpuid$ ./icpuid
Brand: GenuineIntel
Cores: 4
ExtendedFamilyID 00000000
ExtendedModel 00000001
FamilyID 00000006
Model 00000007
SteppingID 0000000a
Hyperthreading 1
CPU has Intel "Core" Processor
fbarchard@muni:~/icpuid$ g++ -fomit-frame-pointer -O3 -m64 -DGAS_ASM -DCPU_DEBUG
icpuid.cpp -o icpuid
fbarchard@muni:~/icpuid$ ./icpuid
Brand: GenuineIntel
Cores: 1
ExtendedFamilyID 00000000
ExtendedModel 00000001
FamilyID 00000006
Model 00000007
SteppingID 0000000a
Hyperthreading 1
CPU has Intel "Core" Processor
fbarchard@muni:~/icpuid$ g++ -fomit-frame-pointer -O3 -fpic -m64 -DGAS_ASM
-DCPU_DEBUG icpuid.cpp -o icpuid
fbarchard@muni:~/icpuid$ ./icpuid
Segmentation fault

I have not found a clean way to do it either, though.
#if defined(__pic__) && defined(__i386__)
void my__cpuidex(int cpu_info[4], int InfoType, int InfoIndex) {
  int dummyeax, dummyecx;
  __asm__ volatile (
    "\n\t    pushl   %%ebx"
    "\n\t    cpuid"
    "\n\t    movl    %%eax, 0(%[cpu_info])"
    "\n\t    movl    %%ebx, 4(%[cpu_info])"
    "\n\t    movl    %%ecx, 8(%[cpu_info])"
    "\n\t    movl    %%edx, 12(%[cpu_info])"
    "\n\t    pop     %%ebx"
    : "=a" (dummyeax), "=c" (dummyecx)  // out
    : [cpu_info]"D" (&cpu_info[0]), "0" (InfoType), "1" (InfoIndex) // in
    : "memory", "%edx"  // modified
  );
}
#else
void my__cpuidex(int cpu_info[4], int InfoType, int InfoIndex) {
  int dummyeax, dummyecx;
  __asm__ volatile (
    "\n\t    cpuid"
    "\n\t    movl    %%eax, 0(%[cpu_info])"
    "\n\t    movl    %%ebx, 4(%[cpu_info])"
    "\n\t    movl    %%ecx, 8(%[cpu_info])"
    "\n\t    movl    %%edx, 12(%[cpu_info])"
    : "=a" (dummyeax), "=c" (dummyecx)  // out
    : [cpu_info]"D" (&cpu_info[0]), "0" (InfoType), "1" (InfoIndex) // in
    : "memory", "%ebx", "%edx"  // modified
  );
}
#endif

+
 void CPU::Initialize() {
+#if defined(ARCH_CPU_X86_FAMILY)
   int cpu_info[4] = {-1};
   char cpu_string[0x20];
 
   // __cpuid with an InfoType argument of 0 returns the number of
   // valid Ids in CPUInfo[0] and the CPU identification string in
   // the other three array elements. The CPU identification string is
   // not in linear order. The code below arranges the information
   // in a human readable form.
   //
   // More info can be found here:
   // http://msdn.microsoft.com/en-us/library/hskdteyh.aspx
-  __cpuid(cpu_info, 0);
+  cpuid(cpu_info, 0);
   int num_ids = cpu_info[0];
   memset(cpu_string, 0, sizeof(cpu_string));
   *(reinterpret_cast<int*>(cpu_string)) = cpu_info[1];
   *(reinterpret_cast<int*>(cpu_string+4)) = cpu_info[3];
   *(reinterpret_cast<int*>(cpu_string+8)) = cpu_info[2];
 
   // Interpret CPU feature information.
   if (num_ids > 0) {
-    __cpuid(cpu_info, 1);
+    cpuid(cpu_info, 1);
     stepping_ = cpu_info[0] & 0xf;
     model_ = (cpu_info[0] >> 4) & 0xf;
     family_ = (cpu_info[0] >> 8) & 0xf;
     type_ = (cpu_info[0] >> 12) & 0x3;
     ext_model_ = (cpu_info[0] >> 16) & 0xf;
     ext_family_ = (cpu_info[0] >> 20) & 0xff;
     cpu_vendor_ = cpu_string;
+    has_sse2_ = (cpu_info[3] & (1<<26)) != 0;

[fbarchard, 2011/02/15 01:42:56]

add has_ssse3_ while you're at it?  Or a todo

   }
+#endif
 }
 
+
+
 }  // namespace base