asm1_b.s

s3c44b0 arm指令实验

#*********************************************************************************************
# NAME:		asm1_a.s																		 *
# Author: 	Embest																			 *
# Desc:		ARM instruction examples														 *
# History:	shw.He 2005.02.22																 *
#*********************************************************************************************

/*------------------------------------------------------------------------------------------*/
/*	 								constant define						 				    */
/*------------------------------------------------------------------------------------------*/
.equ	x, 45										/* x=45 */
.equ	y, 64										/* y=64 */
.equ	z, 87										/* z=87 */
.equ	stack_top, 0x1000							/* define the top address for stacks */
.global _start

/*------------------------------------------------------------------------------------------*/
/*	 								code								 				    */
/*------------------------------------------------------------------------------------------*/
.text

_start:												/* code start */
		mov		r0, #x 								/* put x value into R0  */
		mov		r0, r0, lsl #8						/* R0 = R0 << 8  */
		mov		r1, #y								/* put y value into R1  */
		add		r2, r0, r1, lsr #1					/* R2 = (R1>>1) + R0 */
		MOV		sp, #0x1000
		STR		r2, [sp]

		mov		r0, #z								/* put z value into R0  */
		and		r0, r0, #0xFF						/* get low 8 bit from R0 */
		mov		r1, #y								/* put y value into R1  */
		add		r2, r0, r1, lsr #1					/* R2 = (R1>>1) + R0 */
		
		LDR		r0, [sp]							/* put y value into R1 */
		MOV		r1, #0x01
		ORR		r0, r0, r1
		mov		r1, R2								/* put y value into R1  */
		add		r2, r0, r1, lsr #1					/* R2 = (R1>>1) + R0  */

stop:
		b		stop								/* end the code ，cycling*/
.end