Mega Code Archive
Is my CPU branded
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Title: Is my CPU branded?
Question: 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 tring, provided the CPUID instuction is available.
Answer:
function GetBrandString:string;
{Newer 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 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;
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