String reversal assembly pic24

stringReverse.asm

.include "xc.inc"

.bss
sz_1:   .space 16        
sz_2:   .space 16        
mplab_x_bug: .space 2


.section .const, psv

sz_1_const: .asciz "Upper/LOWER."
sz_2_const: .asciz "mIXeD CaSe.."

.text

.global __reset          
__reset:
mov #__SP_init, W15   
mov #__SPLIM_init, W0
mov W0, SPLIM

call init_variables
rcall main
;reset ;not sure if we need this for now(?)

main:
;load addr for s1, s2
mov #sz_1, W1
mov #sz_2, W2
;start dostr
rcall dostr

;dostr(*s1, *s2)
;DEFINITIONS:
;*sz_1 w1
;*sz_2 w2
;w3 -> tmp
;w4 -> c
dostr:

;(i.e *psz_1 - 0, then check if the result is not zero,
; if result was 0 then *psz_1 must have been 0
mov[W1], W5
cp.b W5, #0
bra Z END_PROGRAM

mov.b [W1], W3
mov.b [W2], W4

cp.b W4, #0X2F; c - 0X2F
bra leu, LOOP1_ELSE ; if(c <= 0x2f go to the else{}
xor.b W4, #0X20, [W1];psz_1 = c ^ 0x20
rcall LOOP1_END

LOOP1_ELSE:
mov.b W4, [W1];*sz_1 = c
rcall LOOP1_END


LOOP1_END:
mov.b W3, [W3]
inc [W1], [W1]
inc [W2], [W2]
rcall dostr

END_DOSTR:
;do w/e the f