99 lines
1.8 KiB
NASM
99 lines
1.8 KiB
NASM
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; JABHACK.ASM
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.386C
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IDEAL
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MODEL MEDIUM
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EXTRN LDIV@:far
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;============================================================================
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DATASEG
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EXTRN _intaddr:word
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;============================================================================
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CODESEG
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; Hacked up Juan Jimenez's code a bit to just return 386/not 386
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PROC _CheckIs386
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PUBLIC _CheckIs386
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pushf ; Save flag registers, we use them here
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xor ax,ax ; Clear AX and...
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push ax ; ...push it onto the stack
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popf ; Pop 0 into flag registers (all bits to 0),
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pushf ; attempting to set bits 12-15 of flags to 0's
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pop ax ; Recover the save flags
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and ax,08000h ; If bits 12-15 of flags are set to
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cmp ax,08000h ; zero then it's 8088/86 or 80188/186
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jz not386
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mov ax,07000h ; Try to set flag bits 12-14 to 1's
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push ax ; Push the test value onto the stack
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popf ; Pop it into the flag register
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pushf ; Push it back onto the stack
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pop ax ; Pop it into AX for check
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and ax,07000h ; if bits 12-14 are cleared then
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jz not386 ; the chip is an 80286
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mov ax,1 ; We now assume it's a 80386 or better
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popf
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retf
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not386:
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xor ax,ax
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popf
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retf
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ENDP
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PROC _jabhack2
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PUBLIC _jabhack2
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jmp @@skip
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@@where:
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int 060h
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retf
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@@skip:
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push es
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mov ax,seg LDIV@
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mov es,ax
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mov ax,[WORD PTR @@where]
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mov [WORD FAR es:LDIV@],ax
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mov ax,[WORD PTR @@where+2]
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mov [WORD FAR es:LDIV@+2],ax
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mov ax,offset @@jabdiv
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mov [_intaddr],ax
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mov ax,seg @@jabdiv
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mov [_intaddr+2],ax
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pop es
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retf
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@@jabdiv:
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add sp,4 ;Nuke IRET address, but leave flags
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push bp
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mov bp,sp ;Save BP, and set it equal to stack
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cli
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mov eax,[bp+8]
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cdq
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idiv [DWORD PTR bp+12]
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mov edx,eax
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shr edx,16
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pop bp ;Restore BP
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popf ;Restore flags (from INT)
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retf 8 ;Return to original caller
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ENDP
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END
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