Get CPU Brand

Get CPU Brand

Recent Intel and AMD processors have an extend CPUID function call, that returns the name of the processor. In earlier cpu models you had to use the version and feature information function of CPUID to look up names in a string list of your own.

The function GetBrandString shows how to access the brand string, provided the CPUID instuction is available.

Some AMD (K5 Model 1/2/3,K6 Model 6/7, K6 -2 Model 8, K6-III Model 9, all Athlon and Duron) and Intel Pentium IV support a Processor Name String that is a 0 byte terminated string that can be a up to 47 characters long (terminating 0 byte excluded) terminating.

function GetBrandString : string;

  function CPUIDAvail : boolean; assembler;
  {Thests wheter the CPUID instruction is available}
  asm
    pushfd                // get flags into ax
    pop   eax             // save a copy on the stack
    mov   edx,eax
    xor   eax, 0200000h   // flip bit 21
    push  eax             // load new value into flags
    popfd                 // get them back
    pushfd
    pop   eax
    xor   eax,edx
    and   eax, 0200000h   // clear all but bit 21
    shr   eax, 21
  end;

const
  CPUID=$a20f;
var
  s:array[0..48] of char;
begin
  fillchar(s,sizeof(s),0);
  if CPUIDAvail then begin
    asm
      //save regs
      push ebx
      push ecx
      push edx
      //check if necessary extended CPUID calls are
      //supported, if not return null string
      mov  eax,080000000h
      dw   CPUID
      cmp  eax,080000004h
      jb   @@endbrandstr
      //get first name part
      mov  eax,080000002h
      dw   CPUID
      mov  longword(s[0]),eax
      mov  longword(s[4]),ebx
      mov  longword(s[8]),ecx
      mov  longword(s[12]),edx
      //get second name part
      mov  eax,080000003h
      dw   CPUID
      mov  longword(s[16]),eax
      mov  longword(s[20]),ebx
      mov  longword(s[24]),ecx
      mov  longword(s[28]),edx
      //get third name part
      mov  eax,080000004h
      dw   CPUID
      mov  longword(s[32]),eax
      mov  longword(s[36]),ebx
      mov  longword(s[40]),ecx
      mov  longword(s[44]),edx
    @@endbrandstr:
      //restore regs
      pop  edx
      pop  ecx
      pop  ebx
     end;
   end;
   result:=StrPas(s);
end;