8085 assembly #2: Task #1

7/1/2018

For my first task/learning excercise I wanted to start learning about using memory. To do this I came up with a simple goal: add the numbers together in memory from the memory location 0x00 until the first 0x00 byte is read. While a simple task in a language I am use to like C, I found it difficult to picture how I should control the registers to store and move around the bytes.

The final code to achieve this task (memory filled in manually inside the simulator):

; ADD NUMBERS IN MEMORY 00H -> NEXT 00H BYTE, STORE RESULT IN C

JMP START
START:	LXI H,00H	; HL AS MEMORY POINTER
	MVI C,00H	; CLEAR C
	MOV B,C		; CLEAR B
NEXT:	MOV A,M		; SET ACCUMULATOR TO VALUE AT MEMORY ADDRESS
	CPI 00H		; COMPARE ACCUMULATOR WITH 00H
	JZ END		; JUMP IF ZERO
	INX H		; INCREASE POINTER
	JMP SAVE	; JUMP TO SAVE
SAVE:	MOV B,A		; STORE ACCUMULATOR IN B
	MOV A,C		; MOVE C INTO ACCUMULATOR
	ADD B		; ADD B
	MOV C,A		; STORE NEW ADDED VALUED IN B
	MVI A,00H	; CLEAR ACCUMULATOR
	MOV B,A		; CLEAR B
	JMP NEXT	; NEXT BYTE
 END:	HLT		; HALT