_cpuinfo.asm

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;****************************************************************************
;*
;*                  SciTech OS Portability Manager Library
;*
;*  ========================================================================
;*
;*    The contents of this file are subject to the SciTech MGL Public
;*    License Version 1.0 (the "License"); you may not use this file
;*    except in compliance with the License. You may obtain a copy of
;*    the License at http://www.scitechsoft.com/mgl-license.txt
;*
;*    Software distributed under the License is distributed on an
;*    "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
;*    implied. See the License for the specific language governing
;*    rights and limitations under the License.
;*
;*    The Original Code is Copyright (C) 1991-1998 SciTech Software, Inc.
;*
;*    The Initial Developer of the Original Code is SciTech Software, Inc.
;*    All Rights Reserved.
;*
;*  ========================================================================
;*
;* Language:    NASM or TASM Assembler
;* Environment: Intel 32 bit Protected Mode.
;*
;* Description: Code to determine the Intel processor type.
;*
;****************************************************************************

        IDEAL

include "scitech.mac"

header      _cpuinfo

begdataseg  _cpuinfo                ; Start of data segment

cache_id    db  "01234567890123456"
intel_id    db  "GenuineIntel"      ; Intel vendor ID
cyrix_id    db  "CyrixInstead"      ; Cyrix vendor ID
amd_id      db  "AuthenticAMD"      ; AMD vendor ID
idt_id      db  "CentaurHauls"      ; IDT vendor ID

CPU_IDT     EQU 01000h              ; Flag for IDT processors
CPU_Cyrix   EQU 02000h              ; Flag for Cyrix processors
CPU_AMD     EQU 04000h              ; Flag for AMD processors
CPU_Intel   EQU 08000h              ; Flag for Intel processors

enddataseg  _cpuinfo

begcodeseg  _cpuinfo                ; Start of code segment

ifdef   USE_NASM
%macro mCPU_ID 0
db  00Fh,0A2h
%endmacro
else
MACRO   mCPU_ID
db  00Fh,0A2h
ENDM
endif

ifdef   USE_NASM
%macro mRDTSC 0
db  00Fh,031h
%endmacro
else
MACRO   mRDTSC
db  00Fh,031h
ENDM
endif

;----------------------------------------------------------------------------
; bool _CPU_check80386(void)
;----------------------------------------------------------------------------
; Determines if we have an i386 processor.
;----------------------------------------------------------------------------
cprocstart  _CPU_check80386

        enter_c

        xor     edx,edx             ; EDX = 0, not an 80386
        mov     bx, sp
ifdef   USE_NASM
        and     sp, ~3
else
        and     sp, not 3
endif
        pushfd                      ; Push original EFLAGS
        pop     eax                 ; Get original EFLAGS
        mov     ecx, eax            ; Save original EFLAGS
        xor     eax, 40000h         ; Flip AC bit in EFLAGS
        push    eax                 ; Save new EFLAGS value on
                                    ;   stack
        popfd                       ; Replace current EFLAGS value
        pushfd                      ; Get new EFLAGS
        pop     eax                 ; Store new EFLAGS in EAX
        xor     eax, ecx            ; Can't toggle AC bit,
                                    ;   processor=80386
        jnz     @@Done              ; Jump if not an 80386 processor
        inc     edx                 ; We have an 80386

@@Done: push    ecx
        popfd
        mov     sp, bx
        mov     eax, edx
        leave_c
        ret

cprocend

;----------------------------------------------------------------------------
; bool _CPU_check80486(void)
;----------------------------------------------------------------------------
; Determines if we have an i486 processor.
;----------------------------------------------------------------------------
cprocstart  _CPU_check80486

        enter_c

; Distinguish between the i486 and Pentium by the ability to set the ID flag
; in the EFLAGS register. If the ID flag is set, then we can use the CPUID
; instruction to determine the final version of the chip. Otherwise we
; simply have an 80486.

; Distinguish between the i486 and Pentium by the ability to set the ID flag
; in the EFLAGS register. If the ID flag is set, then we can use the CPUID
; instruction to determine the final version of the chip. Otherwise we
; simply have an 80486.

        pushfd                      ; Get original EFLAGS
        pop     eax
        mov     ecx, eax
        xor     eax, 200000h        ; Flip ID bit in EFLAGS
        push    eax                 ; Save new EFLAGS value on stack
        popfd                       ; Replace current EFLAGS value
        pushfd                      ; Get new EFLAGS
        pop     eax                 ; Store new EFLAGS in EAX
        xor     eax, ecx            ; Can not toggle ID bit,
        jnz     @@1                 ; Processor=80486
        mov     eax,1               ; We dont have a Pentium
        jmp     @@Done
@@1:    mov     eax,0               ; We have Pentium or later
@@Done: leave_c
        ret

cprocend

;----------------------------------------------------------------------------
; bool _CPU_checkClone(void)
;----------------------------------------------------------------------------
; Checks if the i386 or i486 processor is a clone or genuine Intel.
;----------------------------------------------------------------------------
cprocstart  _CPU_checkClone

        enter_c

        mov     ax,5555h            ; Check to make sure this is a 32-bit processor
        xor     dx,dx
        mov     cx,2h
        div     cx                  ; Perform Division
        clc
        jnz     @@NoClone
        jmp     @@Clone
@@NoClone:
        stc
@@Clone:
        pushfd
        pop     eax                 ; Get the flags
        and     eax,1
        xor     eax,1               ; EAX=0 is probably Intel, EAX=1 is a Clone

        leave_c
        ret

cprocend

;----------------------------------------------------------------------------
; bool _CPU_haveCPUID(void)
;----------------------------------------------------------------------------
; Determines if we have support for the CPUID instruction.
;----------------------------------------------------------------------------
cprocstart  _CPU_haveCPUID

        enter_c

ifdef flatmodel
        pushfd                      ; Get original EFLAGS
        pop     eax
        mov     ecx, eax
        xor     eax, 200000h        ; Flip ID bit in EFLAGS
        push    eax                 ; Save new EFLAGS value on stack
        popfd                       ; Replace current EFLAGS value
        pushfd                      ; Get new EFLAGS
        pop     eax                 ; Store new EFLAGS in EAX
        xor     eax, ecx            ; Can not toggle ID bit,
        jnz     @@1                 ; Processor=80486
        mov     eax,0               ; We dont have CPUID support
        jmp     @@Done
@@1:    mov     eax,1               ; We have CPUID support
else
        mov     eax,0               ; CPUID requires 32-bit pmode
endif
@@Done: leave_c
        ret

cprocend

;----------------------------------------------------------------------------
; uint _CPU_checkCPUID(void)
;----------------------------------------------------------------------------
; Determines the CPU type using the CPUID instruction.
;----------------------------------------------------------------------------
cprocstart  _CPU_checkCPUID

        enter_c

        xor     eax, eax            ; Set up for CPUID instruction
        mCPU_ID                     ; Get and save vendor ID
        cmp     eax, 1              ; Make sure 1 is valid input for CPUID
        jl      @@Fail              ; We dont have the CPUID instruction
        xor     eax,eax             ; Assume vendor is unknown

; Check for GenuineIntel processors

        LEA_L   esi,intel_id
        cmp     [DWORD esi], ebx
        jne     @@NotIntel
        cmp     [DWORD esi+4], edx
        jne     @@NotIntel
        cmp     [DWORD esi+8], ecx
        jne     @@NotIntel
        mov     eax,CPU_Intel       ; Flag that we have GenuineIntel
        jmp     @@FoundVendor

; Check for CyrixInstead processors

@@NotIntel:
        LEA_L   esi,cyrix_id
        cmp     [DWORD esi], ebx
        jne     @@NotCyrix
        cmp     [DWORD esi+4], edx
        jne     @@NotCyrix
        cmp     [DWORD esi+8], ecx
        jne     @@NotCyrix
        mov     eax,CPU_Cyrix       ; Flag that we have CyrixInstead
        jmp     @@FoundVendor

; Check for AuthenticAMD processors

@@NotCyrix:
        LEA_L   esi,amd_id
        cmp     [DWORD esi], ebx
        jne     @@NotAMD
        cmp     [DWORD esi+4], edx
        jne     @@NotAMD
        cmp     [DWORD esi+8], ecx
        jne     @@NotAMD
        mov     eax,CPU_AMD         ; Flag that we have AuthenticAMD
        jmp     @@FoundVendor

; Check for CentaurHauls processors

@@NotAMD:
        LEA_L   esi,idt_id
        cmp     [DWORD esi], ebx
        jne     @@NotIDT
        cmp     [DWORD esi+4], edx
        jne     @@NotIDT
        cmp     [DWORD esi+8], ecx
        jne     @@NotIDT
        mov     eax,CPU_IDT         ; Flag that we have AuthenticIDT
        jmp     @@FoundVendor

@@NotIDT:

@@FoundVendor:
        push    eax
        xor     eax, eax
        inc     eax
        mCPU_ID                     ; Get family/model/stepping/features
        and     eax, 0F00h
        shr     eax, 8              ; Isolate family
        and     eax, 0Fh
        pop     ecx
        or      eax,ecx             ; Combine in the clone flag
@@Done: leave_c
        ret

@@Fail: xor     eax,eax
        jmp     @@Done

cprocend

;----------------------------------------------------------------------------
; uint _CPU_getCPUIDModel(void)
;----------------------------------------------------------------------------
; Determines the CPU type using the CPUID instruction.
;----------------------------------------------------------------------------
cprocstart  _CPU_getCPUIDModel