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|
.386
.MODEL small
.DATA
.CODE
IF 0
#define PEL_WRITE_ADR 0x3c8
#define PEL_READ_ADR 0x3c7
#define PEL_DATA 0x3c9
ENDIF
;================
;
; I_DivException
;
;================
PROC I_DivException_
PUBLIC I_DivException_
mov edx,03c9h
mov al,63
out dx,al
mov ebx,0ffffffh
mov eax,[ebx]
retf
ENDP
;================
;
; I_SetDivException
;
;================
PROC I_SetDivException_
PUBLIC I_SetDivException_
pusha
mov eax,0212h
mov ebx,0
mov ecx,cs
mov edx,OFFSET I_DivException_
int 31h
jnc good
popa
mov eax,0
ret
good:
popa
mov eax,1
ret
ENDP
;================
;
; I_ReadJoystick
;
; Read the absolute joystick values
; returns false if not connected
;================
.data
_joystickx dd 0
_joysticky dd 0
PUBLIC _joystickx, _joysticky
.code
PROC I_ReadJoystick_
PUBLIC I_ReadJoystick_
pusha
pushf ; state of interrupt flag
cli
mov dx,0201h
in al,dx
out dx,al ; Clear the resistors
mov ah,1 ; Get masks into registers
mov ch,2
xor esi,esi ; Clear count registers
xor edi,edi
xor ebx,ebx ; Clear high byte of bx for later
mov ebp,10000 ; joystick is disconnected if value is this big
jloop:
in al,dx ; Get bits indicating whether all are finished
dec ebp ; Check bounding register
jz bad ; We have a silly value - abort
mov bl,al ; Duplicate the bits
and bl,ah ; Mask off useless bits (in [xb])
add esi,ebx ; Possibly increment count register
mov cl,bl ; Save for testing later
mov bl,al
and bl,ch ; [yb]
add edi,ebx
add cl,bl
jnz jloop ; If both bits were 0, drop out
done:
mov [_joystickx],esi
shr edi,1 ; because 2s were added
mov [_joysticky],edi
popf ; restore interrupt flag
popa
mov eax,1 ; read was ok
ret
bad:
popf ; restore interrupt flag
popa
xor eax, eax ; read was bad
ret
ENDP
END
|
