Re: A85: Matix

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Re: A85: Matix

Why don't you just use a matrix in the TEXT_MEM?  You won't have to
worry about checksums if you do this.  All you have to do is copy the
matrix from your program body into TEXT_MEM using the ldir
instruction.  then when you want to access the matrix, you will never
even have to add PROGRAM_ADDR (since you are using Zshell).  That is
the easiest way to do it.

TXTMTRX	=	TEXT_MEM+X	;64 bytes for matrix
				;X is an integer after the previous
				;variable
NEXTVAR	=	TEXT_MEM+X+N	;make sure next variable doesn't
				;start for N bytes, where N is the
				;number of bytes of your matrix

Your matrix is defined at the bottom:

;this matrix is 64 bytes, so N would be 64 bytes in this case
Matrix:
.db 0,1,0,1,0,1,0,1
.db 1,0,1,0,1,0,1,0
.db 0,1,0,1,0,1,0,1
.db 1,0,1,0,1,0,1,0
.db 0,1,0,1,0,1,0,1
.db 1,0,1,0,1,0,1,0
.db 0,1,0,1,0,1,0,1
.db 1,0,1,0,1,0,1,0


In your code, you have a function:
CopyMatrixToTEXT:
  ld bc,N		;N would be 64 in this example
  ld de,TXTMTRX
  ld hl,Matrix
  ldir
  ret

Now in your code, where before you would have called the function like
Andreas wrote below with:

  ld de,(PROGRAM_ADDR)
  ld hl,Matrix
  add hl,de
  ex de,hl		;matrix location in de
  ld a,(XPOS)
  ld b,a		;x pos in b
  ld a,(YPOS)
  ld c,a		;y pos in c
  CALL_(EssFunction)

You would now call it as such:

  ld de,TXTMTRX		;matrix location in de
  ld a,(XPOS)
  ld b,a		;x pos in b
  ld a,(YPOS)
  ld c,a		;y pos in c
  CALL_(EssFunction)

-mike pearce

On Sun, 07 Sep 1997 18:39:02 -0500, you wrote:

>I tried that and then put lh (hl),a and it didn't work andgave me a bad
>checksum!  Here is how I'm calling my matrix, if this matters, and I
>have the number I want stored in A!  but nothing is working!  Does
>anyone know why or ahve they run across this?
>
>John
>
>Ess Andreas wrote:
>> 
>> B = x coordinate
>> C = y coordinate
>> DE = addr of your matrix-like gameboard
>> 
>>         ld      H, 0
>>         ld      L, C
>>         add     HL, HL
>>         add     HL, HL
>>         add     HL, HL  ;you have an 8x8 matrix, right?
>>         ld      C, B
>>         ld      B, 0
>>         add     HL, BC
>>         add     HL, DE
>> 
>> Now you can perform ld A, (HL), ld (HL), A etc. etc.
>>         Andreas
>
References: