Hey guys what I'm trying to do is to sum two arrays and return a new array; for example if given

  uint8_t a[] = { 2, 4, 6};
  uint8_t b[] = {1, 2, 3};

I should get { 3, 6, 9} What I'm trying to do is have a .ino file call on an assembly file that will do this in assembly and not in C and this is what I currently have in assembly:

// mimics void sumArrays(uint8_t *a, uint8_t *b, uint8_t *c, byte length){} method
    .global sumArrays
    sumArrays:
      //r18 is the byte length
      //r24 and r25 first array 31,30
      //r23 and r22 second array 29,28
      //r21 and r20 third array 27, 26

      mov r30, r24
      mov r31, r25
      mov r28, r22
      mov r29, r23
      mov r26, r20
      mov r27, r21
      ldi r17, 0 //counter variable
      ldi r19, 1
      call printRegs
      //jmp sumLoop
 

         ret
    sumLoop:
      cp r17, r18
      brge endSumLoop
      ldi r16, 0
      add r16, Z+
      add r16, Y+
      st X+, r16
      add r17, r23
      jmp sumLoop:
    
    endSumLoop: 
      ret

However, I get sketch/assignment13.S:65: Error: constant value required which is most likely from the

add r16, Z+
add r16, Y+

Lines but otherwise, how would I add it to a temporary variable while progressing the pointer?

Hey guys what I'm trying to do is to sum two arrays and return a new array; for example if given

  uint8_t a[] = {2, 4, 6};
  uint8_t b[] = {1, 2, 3};

I should get { 3, 6, 9} What I'm trying to do is have a .ino file call on an assembly file that will do this in assembly and not in C and this is what I currently have in assembly:

// mimics void sumArrays(uint8_t *a, uint8_t *b, uint8_t *c, byte length){} method
    .global sumArrays
    sumArrays:
      //r18 is the byte length
      //r24 and r25 first  array 31,30
      //r23 and r22 second array 29,28
      //r21 and r20 third  array 27,26

      mov r30, r24
      mov r31, r25
      mov r28, r22
      mov r29, r23
      mov r26, r20
      mov r27, r21
      ldi r17, 0 //counter variable
      ldi r19, 1
      call printRegs
      //jmp sumLoop

      ret 

    sumLoop:
      cp r17, r18
      brge endSumLoop
      ldi r16, 0
      add r16, Z+
      add r16, Y+
      st X+, r16
      add r17, r23
      jmp sumLoop:
    
    endSumLoop: 
      ret

However, I get sketch/assignment13.S:65: Error: constant value required which is most likely from the

add r16, Z+
add r16, Y+

Lines but otherwise, how would I add it to a temporary variable while progressing the pointer?