Need help with string reverse function ; ; string_reverse.asm .include \"m2560de

Question

 Need help with string reverse function ; ; string_reverse.asm  .include "m2560def.inc"  ;SPH, SPL, RAMEND, etc. are defined in "m2560def.inc"  .cseg         ; initialize the stack pointer         ldi r16, low(RAMEND)         out SPL, r16         ldi r16, high(RAMEND)         out SPH, r16                          ; prepare the parameters X and Z         ldi ZH, high(src<<1)         ldi ZL, low(src<<1)         ldi XH, high(dest)         ldi XL, low(dest)          ;call subroutine void strcpy(src, dest)         call strcpy          ;call subroutine: str_reverse(dest, mesg)         ;write your code here                   ; program ends here done:          jmp done   ; This subroutine (function) copies a null-terminated string  ; starting at some (source) program memory address to a location starting  ; at some (destination) memory address. ; The memory addresses are passed to the subroutine via the X and Z pointers strcpy:         ; copy the string from source (Z) to destination (X) next_char:         lpm r23, Z+         st X+, r23         tst r23         brne next_char  strcpy_done:         ret   ; Write your str_reverse subroutine and comments here. ; Using push and pop, reverse the c-string and store at a different memory  ; location. The memory addresses are passed to the subroutine via pointers. str_reverse: ; write your code here   src: .db "Hello, world!", 0 ; c-string format  .dseg .org 0x200 dest: .byte 14 reversed: .byte 14 

Explanation / Answer

include "m2560def.inc" ;SPH, SPL, RAMEND, etc. are defined in "m2560def.inc" .cseg ; initialize the stack pointer ldi r16, low(RAMEND) out SPL, r16 ldi r16, high(RAMEND) out SPH, r16 ; prepare the parameters X and Z ldi ZH, high(src

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