/*
 * p2_7.s
 * Assembly program to toggle the LED0
 */ 

			.section .text
			.global main

			.equ	PORTBDIR, 0x41004480
			.equ	PORTBOUTCLR, 0x41004484
			.equ	PORTBOUTSET, 0x41004488
			.thumb_func

main:
			ldr     r4, =0x40000000     @ make PB30 output
			ldr     r5, =PORTBDIR
			str     r4, [r5]
L1:			ldr     r5, =PORTBOUTCLR    @ clear PB30 to turn on LED0
			str     r4, [r5]
			ldr     r0, =500            @ delay 500 ms
			bl      delay
			ldr     r5, =PORTBOUTSET    @ set PB30 to turn off LED0
			str     r4, [r5]
			ldr     r0, =500            @ delay 500 ms
			bl      delay
			b       L1                  @ loop forever

@ delay milliseconds in R0
delay:			ldr     r1, =332
DL1:			sub     r1, r1, #1
			bne     DL1
			sub     r0, r0, #1
			bne     delay
			bx      lr

			.end