@ writeStrDriver3.s

		@ define system
		.cpu	cortex-a53
        .fpu	neon-fp-armv8
        .syntax	unified

        @ constants
        .equ	STDOUT, 1
        .equ	NEWLINE, 10

        @ program
        .text
        .align	2
        .global	main
        .type	main, %function

main:	@ variables:
		@ 	string buffer size
		@ 	string address
		@ 	newline address
		@	string size

		push	{ r4, r5, r6, r7, lr }	@ save registers

		mov		r4, 4 			@ r4 = string buffer size
		mov		r0, 8			@ get number of bytes for local vars
		sub		sp, sp, r0 		@ allocate memory
		sub		r1, r0, r4		@ get string address offset from sp
		add		r5, sp, r1		@ r5 = string address
		sub		r6, r5, 1		@ r6 = newline address
		mov		r7, 0			@ r7 = string size

		mov		r0, r4			@ pass string buffer size argument
		mov		r1, r5			@ pass string address argument
		bl		readLn			@ execute readLn
		mov		r7, r0			@ get string size

		mov		r0, r7			@ pass string size argument
		mov		r1, r5			@ pass string address argument
		bl		writeStr		@ execute writeStr

		mov		r0, NEWLINE		@ load newline character
		strb	r0, [r6]		@ store newline at newline address

		mov		r0, STDOUT		@ pass output argument
		mov		r1, r6			@ pass address argument
		mov		r2, 1			@ pass size argument
		bl		write			@ execute write

		mov		r0, 0			@ return success
		add		sp, sp, 8		@ deallocate memory
		pop		{ r4, r5, r6, r7, pc }	@ restore registers