CHANGE.PRN

Proc	RESET_DSP	near
       MOV    DX,[_io_addx]
       ADD    DL,6

;       MOV    AL,1                     ;JCM (GET RID OF THIS CODE)
;       OUT    DX,AL                    ;JCM
;       IN     AL,DX                    ;JCM
;@@RDSP05:                              ;JCM
;       INC    AL                       ;JCM
;       JNZ    @@RDSP05                 ;JCM
;       OUT    DX,AL                    ;JCM

                mov al,1                ;JCM (USE THIS INSTEAD)
                out dx,al               ;JCM
                                        ;JCM
                mov cx,20               ;JCM
@@wait:         in al,dx                ;JCM  ;wait > 3 uS
                loop @@wait             ;JCM
                                        ;JCM
                mov al,0                ;JCM  ;drop reset
                out dx,al               ;JCM

       MOV    CL,20H

@@RDSP10:
       CALL   READ_DSP_TIME
       CMP    AL,0AAH
       JE     @@RDSP20
       DEC    CL
       JNZ    @@RDSP10
       MOV    AX,2
       JMP    SHORT @@RDSP90
@@RDSP20:
       SUB    AX,AX
@@RDSP90:
       OR     AX,AX
       RET
       endp


PIC0_val	db	?
PIC1_val	db	?
;-------------------------------------------------
; entry: AL = INTERRUPT NUM                      |
;        DX = new vector ofs, seg is alway CS    |
;        BX = offset of store buffer             :
;-------------------------------------------------
Proc	SETUP_INTERRUPT near
       PUSH   BX
       PUSH   CX
       PUSH   DX

       CLI
	xor	ah,ah		; Zero high byte.
       MOV    CL,AL                    ; preserve interrupt number for use
       cmp     al,8
       jb      @@calc_vect
	add	al,60h	       ; index slcae PIC vectors if IRQ > 7
@@calc_vect:
       ADD    AL,8                     ; calculate interrupt vector addx
       SHL    Ax,1
       SHL    Ax,1
       MOV    DI,AX

       PUSH   ES                       ; setup and preserve interrupt

       SUB    AX,AX
       MOV    ES,AX
       MOV    AX,[ES:DI]
       MOV    [cs:BX],AX               ;JCM
       MOV    [ES:DI],DX

       MOV    AX,[ES:DI+2]
       MOV    [cs:BX+2],AX             ;JCM
       MOV    [ES:DI+2],CS

       POP    ES

	mov	bx,1
	shl	bx,cl
	not	bx
	in	al,0a1h
	mov	[PIC1_val],al
	and	al,bh
	out	0a1h,al
	in	al,21h
	mov	[PIC0_val],al
	and	al,bl
	out	21h,al

       STI
       POP    DX
       POP    CX
       POP    BX
       RET
       endp

;-------------------------------------------------
; entry: AL = INTERRUPT NUM                      |
;        BX = offset to stored addx              |
;-------------------------------------------------
Proc	RESTORE_INTERRUPT	near
       CLI

       MOV    CL,AL

                push bx                 ;JCM
	mov	bx,1
	shl	bx,cl
	in	al,0a1h
	or	al,bh
	and	al,[PIC1_val]	      ;don't kill any interrupts that were
	out	0a1h,al 	    ;initially active
	in	al,21h
	or	al,bl
	and	al,[PIC0_val]
	out	21h,al
                pop bx                  ;JCM

	mov	al,cl		; Get back interrupt number.
	xor	ah,ah

       cmp	al,8
       jb	@@calc_vect
       add	al,60h		; index slave PIC if IRQ > 7
@@calc_vect:
       ADD    AL,8                      ; calculate interrupt vector addx
       SHL    Ax,1
       SHL    Ax,1
       MOV    DI,AX

       PUSH   ES                       ; restore interrupt vector
       SUB    AX,AX
       MOV    ES,AX
       MOV    AX,[cs:BX]               ;JCM
       MOV    [ES:DI],AX

       MOV    AX,[cs:BX+2]             ;JCM
       MOV    [ES:DI+2],AX

       POP    ES


       STI
       RET
       endp