Files
Catacomb3D/JABHACK.ASM
2026-03-12 19:22:23 +01:00

116 lines
2.6 KiB
NASM

; Catacomb 3-D Source Code
; Copyright (C) 1993-2014 Flat Rock Software
;
; This program is free software; you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation; either version 2 of the License, or
; (at your option) any later version.
;
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
; GNU General Public License for more details.
;
; You should have received a copy of the GNU General Public License along
; with this program; if not, write to the Free Software Foundation, Inc.,
; 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
; JABHACK.ASM
.386C
IDEAL
MODEL MEDIUM
EXTRN LDIV@:far
;============================================================================
DATASEG
EXTRN _intaddr:word
;============================================================================
CODESEG
; Hacked up Juan Jimenez's code a bit to just return 386/not 386
PROC _CheckIs386
PUBLIC _CheckIs386
pushf ; Save flag registers, we use them here
xor ax,ax ; Clear AX and...
push ax ; ...push it onto the stack
popf ; Pop 0 into flag registers (all bits to 0),
pushf ; attempting to set bits 12-15 of flags to 0's
pop ax ; Recover the save flags
and ax,08000h ; If bits 12-15 of flags are set to
cmp ax,08000h ; zero then it's 8088/86 or 80188/186
jz not386
mov ax,07000h ; Try to set flag bits 12-14 to 1's
push ax ; Push the test value onto the stack
popf ; Pop it into the flag register
pushf ; Push it back onto the stack
pop ax ; Pop it into AX for check
and ax,07000h ; if bits 12-14 are cleared then
jz not386 ; the chip is an 80286
mov ax,1 ; We now assume it's a 80386 or better
popf
retf
not386:
xor ax,ax
popf
retf
ENDP
PROC _jabhack2
PUBLIC _jabhack2
jmp @@skip
@@where:
int 060h
retf
@@skip:
push es
mov ax,seg LDIV@
mov es,ax
mov ax,[WORD PTR @@where]
mov [WORD FAR es:LDIV@],ax
mov ax,[WORD PTR @@where+2]
mov [WORD FAR es:LDIV@+2],ax
mov ax,offset @@jabdiv
mov [_intaddr],ax
mov ax,seg @@jabdiv
mov [_intaddr+2],ax
pop es
retf
@@jabdiv:
add sp,4 ;Nuke IRET address, but leave flags
push bp
mov bp,sp ;Save BP, and set it equal to stack
cli
mov eax,[bp+8]
cdq
idiv [DWORD PTR bp+12]
mov edx,eax
shr edx,16
pop bp ;Restore BP
popf ;Restore flags (from INT)
retf 8 ;Return to original caller
ENDP
END