harikrishnan's micro86
basic2:

; shows some of the data addressing modes of 8086
; step this program

; immediate addressing
	mov	BX,1011 ; copy 1011 to bx
	mov	AL,50	; copy 50 to AL
		
; register addressing
	mov	cx,bx ; copy bx to cx

; direct addressing
	mov	[1010] , AL ; place AL's contents to
		   ; memory address 1010
		   ; see ram while stepping

; register indirect addressing
	mov	[bx], AL ; place AL's contents to
		  ; memory address bx
		  ; here bx is 1011. so 
		  ; AL is copied to [1011], in effect.
		  		  

; base plus index
	mov	ch,[bx+si]; here si = 0 and bx = 1011
		 ; thus a byte from memory location bx+si
		 ; ie,(1011+0) is copied to ch
	hlt




basic3:
; shows some arithmetic instructions
; step the program and watch registers
; note:- all numbers are in hex form

	Add	ax,5	; ax = ax + 5
	dec	ax	; ax = ax - 1 (decrement)
	inc	ax	; ax = ax + 1 (increment)
	sub	ax,2	; ax = ax - 2
		
; 8-bit multiplication and division
	mov	bl, 2	; copy 2 to bl
	mul	bl	; aX = al * bl; (result is 16-bit)
	
	mov	dh,4	; copy 4 to dh
	div	dh	; aL = aX / dh (quotient in AL)
			; remainder in ah
	hlt



basic4:
; demo of a loop
	;;
	mov	cx,5 ; copy count to cx
		    ; cx determines how many times
		    ; loop should execute
		    		    
NEXT:		    ; 'NEXT' is a label
	inc	ax; ax  = ax + 1 ;
	
	loop	NEXT ; goto NEXT if cx not zero
	hlt	
;loop instruction does two things
;first cx = cx - 1
;next it checks whether cx is 0
;if cx is not zero,it jumps to a label (here 'NEXT')
;if cx is zero, execution of next instruction is continued



basic5:
; demo of a loop using 'jmp'
; step this program
		    		    
START:		    ; 'START' is a label

	Add	cx,3 ; your instructions
	Add	cx,3 ; your instructions
	Add	cx,3 ;  your instructions
	
	jmp	START ; jump to START
		
; 'jmp' jumps to the given label


basic6:
; demo of a procedure
; 'call' is used to call a procedure
; procedures can be called  many times
; step the program
; it does'nt do anything in particular

	mov	ax,ffff ;
	call	myproc1  ; call the procedure myproc
	mov	ah,ee   ;
	call	myproc2  ; call the procedure myproc again
	hlt		; stop 

proc	myproc1		; this is how we name a procedure
	dec	ax	; instructions to do
	ret		; return from here

proc	myproc2		; this is how we name a procedure
	inc	ax	; instructions to do
	ret		; return from here