;
;     CPE 221 Assembly Example
;     3/6/18	
;     This code takes the absolute value of a number.

        AREA ABS, CODE, READONLY
	    ENTRY
	    LDR     r0, num
	    CMP     r0, #0
	    BPL     done
	    ;0 RSB    r0, r0, #0
        ;1 ADD     r1, r0, r0
        ;1 SUB     r0, r0, r1
        ;2 MVN     r0, r0
        ;2 ADD     r0, r0, #1
        ;3 MOV     r1, #0
        ;3 SUB     r0, r1, r0
        MOV     r1, #-1
        MUL     r2, r0, r1
        MOV     r0, r2
        MOV     r5, #47
        PUSH    {r5}
done    STR     r0, abs_num
num     DCD     -5
abs_num SPACE   4
        END