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CPU Detect
Submitted by |
I've had programmers block for a while now and I just had to write something. I remembered
something about the assembler 'cpuid' instruction so I decided to test it out. I figured this sort
of thing might be useful if I am writting an application that required a certain processor or I was
just writting really optimized code. So I wrote this and compiled it as a static library. I also
wrote an application that will spit out the features of your processor, thats availabe at my website.
Heres the first part of the code, the [.h] file. Each of the differant features detectable are defined.
The cpuID function returns a pointer to the processor string (like the one in system under control
panel for you Windows people, like the string GenuineIntel or AuthenticAMD)
(Editor's note: see cpuid.h)
And now the actual function definitions. Some of it is written in assembler, I optimized
most of the code (instruction pairing, etc.) but I didn't look at it real closely. One more thing,
you might notice that there isn't a function to tell the frequency of the processor. As far
as I know (after reading the intel documents), 'cpuid' doesn't support this, well the Penium4
does. If you know how, I would love to hear it! Email me if you do-> Assembler015@hotmail.com
(Editor's note: see cpuid.c)
If you have any questions, email me. You can freely use this code, I don't care,
but if you do, I'd at least like to hear from you! Hope this stuff is useful.
-Andrew
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Currently browsing [cpu.zip] (1,902 bytes) - [cpuID.h] - (3,085 bytes)
#ifndef _CPUID_H_
#define _CPUID_H_
/*
When cpuid is called with a value of 0 in the
EAX register, it returns a list of values in the
EDX register. Each bit represents a feature
(excluding reserved bits). If the bit is set, the
feature exists. If it's cleared the feature
isn't supported.
*/
#define CHECKFEATURE_ERROR 0x10000001 /* cpu feature check had a problem, call cpuFeatures */
#define CHECKFEATURE_X87FPU 0x00000001 /* cpu has x87 fpu */
#define CHECKFEATURE_VMODEE 0x00000002 /* cpu has Virtual 8086 mode enhancement */
#define CHECKFEATURE_DEBEXT 0x00000004 /* cpu has debugging extensions */
#define CHECKFEATURE_PGSEXT 0x00000008 /* cpu has page extensions */
#define CHECKFEATURE_TSCOUN 0x00000010 /* cpu has time stamp counter */
#define CHECKFEATURE_XXMSRS 0x00000020 /* cpu has RDMSR/WRMSR inst support */
#define CHECKFEATURE_PHAEXT 0x00000040 /* cpu has physical address extension */
#define CHECKFEATURE_MCHEXT 0x00000080 /* cpu has machine check exception */
#define CHECKFEATURE_CMPXCH 0x00000100 /* cpu has 8 byte cmp and xchg inst support */
#define CHECKFEATURE_APICON 0x00000200 /* cpu has APIC on chip */
#define CHECKFEATURE_SYSXXX 0x00000800 /* cpu has SYSENTER/SYSLEAVE */
#define CHECKFEATURE_MTRREG 0x00001000 /* cpu has memory type range registers */
#define CHECKFEATURE_PTEBIT 0x00002000 /* cpu has global PTE bit */
#define CHECKFEATURE_MCKARC 0x00004000 /* cpu has machine check architexture */
#define CHECKFEATURE_CMOVIN 0x00008000 /* cpu has CMOV inst support */
#define CHECKFEATURE_PGATTT 0x00010000 /* cpu has page attribute table */
#define CHECKFEATURE_PGSEX2 0x00020000 /* cpu has page size extension */
#define CHECKFEATURE_SERNUM 0x00040000 /* cpu has processor serial number */
#define CHECKFEATURE_CFLUSH 0x00080000 /* processor supports CFLUSH inst */
#define CHECKFEATURE_DBSTOR 0x00200000 /* cpu has debug store */
#define CHECKFEATURE_ACPICT 0x00400000 /* ACPI on processor */
#define CHECKFEATURE_MMXCMP 0x00800000 /* cpu has MMX technology */
#define CHECKFEATURE_FXXSTO 0x01000000 /* cpu supports FXSAVE/FXRSTORE inst */
#define CHECKFEATURE_SSEEXT 0x02000000 /* cpu has SSE extensions */
#define CHECKFEATURE_SSE2EX 0x04000000 /* cpu has sse2 extensions */
#define CHECKFEATURE_SSNOOP 0x08000000 /* cpu supports system snoop */
#define CHECKFEATURE_PTHERM 0x10000000 /* cpu has process thermomitor */
#ifdef _cplusplus
extern "C"
{
#endif
/* When called, obtains a list of features the cpu supports */
extern unsigned int __cdecl cpuFeatures (void);
/*
Pass this one of the above defined features, -1 = error and
if it returns the same value passed the feature exists if it
returns 0 then the feature is un supported
*/
extern unsigned int __cdecl cpuCheckFeature (unsigned int feature);
/*
Returns a pointer to a string that the processor sends to
the EBX, EDX, and ECX registers. e.g. GenuineIntel or
AuthenticAMD.
*/
extern char* __cdecl cpuID (void);
#ifdef _cplusplus
}
#endif
#endif |
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Currently browsing [cpu.zip] (1,902 bytes) - [cpuID.c] - (1,291 bytes)
#include "cpuID.h"
unsigned int cpufeatures = 0; /* cpuFeatures will set this to the appropriate value
to be used by cpuCheckFeature, DONT MODIFY */
unsigned int cpuFeatures (void)
{
unsigned int features;
__asm
{
mov eax, 1 ;set request type to a feature list from processor
cpuid ;send request
lea ebx, features
mov [ebx], edx ;save value
}
cpufeatures = features;
return features;
}
unsigned int cpuCheckFeature (unsigned int feature)
{
if(!cpufeatures) /* cpuFeatures not called ? */
return 0x10000001;
if(cpufeatures&feature) /* feature exists, good- tell user */
return feature;
return 0;
}
char* cpuID (void)
{
static char id[13];
__asm
{
lea ebx, id
mov cl, 0
CLEARID:
inc cl
mov dword ptr [ebx], 0
cmp cl, 13
jb CLEARID
}
__asm
{
xor eax, eax ;set request type to the string ID
cpuid ;send request
xchg eax, ebx ;swap so address register can be used
lea ebx, id ;get destination string offset
mov [ebx], eax ;save first four letters of string
add ebx, 4 ;go up anther four bytes
;repeat for next two registers
mov [ebx], edx
add ebx, 4
mov [ebx], ecx
}
return id; /* return pointer */
} |
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