From c0b13d7fc1eeef8398f4ef4dad2b87ba34a392f4 Mon Sep 17 00:00:00 2001
From: daniel-Jones <daniel@danieljon.es>
Date: Sat, 20 Jan 2018 15:44:42 +1030
Subject: task 4, multiplication using sub routine

---
 TASK4.asm | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 TASK4.asm

diff --git a/TASK4.asm b/TASK4.asm
new file mode 100644
index 0000000..cd32da8
--- /dev/null
+++ b/TASK4.asm
@@ -0,0 +1,29 @@
+; CALLING A ROUTINE AND PREPARE A MEMORY ADDRESS
+; ROUTINE WILL REQUIRE 3 BYTES FIRST NUMBER -> SECOND NUMBER -> RESULT STORAGE
+; ROUTINE WILL MULTIPLY M WITH M+1 AND STORE RESULT IN M+2
+
+JMP START
+			; DEFINE A LIST TO STORE OUR REQUIRED BYTES
+			; DB = DEFINE BYTE
+			; DS = DEFINE STORAGE. OPERAND IS NUMBER OF BYTES
+MULTI1:	DB 05H		; MULTIPLICAND
+	DB 03H		; MULTIPLIER
+	DS 01H		; RESERVES "ONE BYTE OF STORAGE
+START:	LXI H,MULTI1	; LOAD HL AS POINTER TO MULTI1 LIST MEMORY ADDRESS
+	MVI A,0		; CLEAR A
+	MOV D,M		; STORE MULTIPLICAND IN D
+	INX H		; INCREASE MEMORY POINTER TO GET MULTIPLIER
+	MOV E,M		; STORE MULTIPLIER IN E
+	MVI C,00H	; COUNTER SET TO 0
+	CALL MULT	; CALL MULTIPLY FUNCTION
+	INX H 		; INCREASE MEMORY POINTER TO RESULT STORAGE
+	MOV M,A		; STORE RESULT
+	HLT		; HALT
+MULT:	MOV B,A		; STORE A
+	MOV A,C		; MOVE COUNTER INTO A
+	CMP E		; COMPARE MULTIPLIER TO COUNTER
+	MOV A,B		; MOVE B STORAGE BACK INTO A
+	RZ		; RETURN IF ZERO FLAG SET (COUNTER == MULTIPLIER)
+	INR C		; INCREASE COUNTER
+	ADD D		; ADD MULTIPLICAND TO A
+	JMP MULT	; JUMP TO MULT
\ No newline at end of file
-- 
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