Use the cpuid instruction to generate the CPU brand string. And

base/cpu.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/cpu.h"
 
 #include <string.h>
 
 #include "build/build_config.h"
 
@@ skipping 66 matching lines @@
   );
 }
 
 #endif
 #endif  // _MSC_VER
 #endif  // ARCH_CPU_X86_FAMILY
 
 void CPU::Initialize() {
 #if defined(ARCH_CPU_X86_FAMILY)
   int cpu_info[4] = {-1};
-  char cpu_string[0x20];
+  char cpu_string[48];
 
   // __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
+  // in a human readable form. The human readable order is CPUInfo[1] |
+  // CPUInfo[3] | CPUInfo[2]. So we swap the CPUInfo[2] and CPUInfo[3]

[Mark Mentovai, 2012/10/04 15:51:28]

Don’t write “we” in comments. This sentence reads more clearly if you remove the
“we.” And still more clearly if you also remove the “so.”

+  // before memcpy them to cpu_string.

[Mark Mentovai, 2012/10/04 15:51:28]

memcpy is not a verb.

   __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];
+  std::swap(cpu_info[2],cpu_info[3]);

[Mark Mentovai, 2012/10/04 15:51:28]

Space after comma.

+  memcpy(cpu_string, &cpu_info[1], 3*sizeof(int));

[Mark Mentovai, 2012/10/04 15:51:28]

Space around operators. Please familiarize yourself with the style guide.

[jar (doing other things), 2012/10/04 17:42:03]

Please also use sizeof(cpu_info[1)) instead of sizeof(int).

+  cpu_vendor_.assign(cpu_string, 3*sizeof(int));
 
   // Interpret CPU feature information.
   if (num_ids > 0) {
     __cpuid(cpu_info, 1);
     stepping_ = cpu_info[0] & 0xf;
     model_ = ((cpu_info[0] >> 4) & 0xf) + ((cpu_info[0] >> 12) & 0xf0);
     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_mmx_ = (cpu_info[3] & 0x00800000) != 0;
     has_sse_ = (cpu_info[3] & 0x02000000) != 0;
     has_sse2_ = (cpu_info[3] & 0x04000000) != 0;
     has_sse3_ = (cpu_info[2] & 0x00000001) != 0;
     has_ssse3_ = (cpu_info[2] & 0x00000200) != 0;
     has_sse41_ = (cpu_info[2] & 0x00080000) != 0;
     has_sse42_ = (cpu_info[2] & 0x00100000) != 0;
   }
+
+  // Get the brand string of the cpu.
+  __cpuid(cpu_info, 0x80000000);
+  const int parameter_end = 0x80000004;
+
+  if (cpu_info[0] >= parameter_end) {
+    char* cpu_string_ptr = cpu_string;
+
+    for (int parameter = 0x80000002; parameter <= parameter_end;

[jar (doing other things), 2012/10/04 17:42:03]

can you also condition this with:
cpu_string_ptr < &cpu_string[sizeof(cpu_string)]

It makes it much clearer to the reader that you're not overrunning your buffer.

+         parameter++) {
+      __cpuid(cpu_info, parameter);
+      memcpy(cpu_string_ptr, cpu_info, sizeof(cpu_info));
+      cpu_string_ptr += sizeof(cpu_info);
+    }
+    cpu_brand_.assign(cpu_string, sizeof(cpu_string));

[jar (doing other things), 2012/10/04 17:42:03]

Instead of sizeof(cpu_string), please use 
cpu_string_ptr - cpu_string
So that you include exactly what you wrote, and nothing more.

+  }
 #endif
 }
 
 }  // namespace base