; EX58.ASM      C.P. Diduch 2001
;
; Generate the assembler list "file" output for the following
; program by hand then compare with that generated by the DECE
; assembler.
;
;    Author(s):
; Signature(s):                              Date:
;-----------------------------------------------------------------
      	.ORG	0x8000          ; Assemble at 0x8000.
.EQU   	TSF    	0x0000          ; Constant.
				; Program instructions.
				; do {
D0:     XORL    R0, R0, 1       ;    X = X ^ 1;
 	STOREP  0x0002, R0      ;    outport(2, R0);
   	ADDL	R1, NULL, TSF   ;    Y = TSF;
D1:	SUBL	R1, R1, 1    	;    do {Y = Y - 1;}
 	JMPNZ	D1              ;    while(Y != 0)
	JMP	D0		;    }