A83: Re: Sprite routine problems

To: <assembly-83@lists.ticalc.org>
Subject: A83: Re: Sprite routine problems
From: "James Matthews" <jjj@matthewsfamily.fsnet.co.uk>
Date: Wed, 29 Sep 1999 22:25:02 +0100
References: <37F27086.FB562B09@geocities.com>
Reply-To: assembly-83@lists.ticalc.org


At the expense of sounding a prick (I apologize in advance)...just move the
aligned part after the aligned part - then compare to Movax's routine,
because it is pretty much identical. Apart from you use index registers a
bit more (which are slower incidentally - movax avoids using them in aligned
sprite blits)...you've used less pop/pushes, and knowing Movax they're there
for a reason.

Later,

James.

----- Original Message -----
From: Pizza of Hut <pizzaofhut@geocities.com>
To: Assembly-83 <assembly-83@lists.ticalc.org>
Sent: Wednesday, September 29, 1999 9:03 PM
Subject: A83: Sprite routine problems


>
> Hello. I've been working on a 8x8 xor sprite routine to test my z80
> skills. For some reason, the actual sprite wont display, so I'm hoping
> one of you would be able to help me out. The code is as follows:
>
> ;Input: a-x coord, e-y coord, ix-sprite address
> ;Output: 8x8 XOR sprite written to 8e29h
> 8x8_sprite:
>  ld hl,0
> ;*********Calculate addy in graphbuf********
>  sla e  ;Do y*12
>  sla e
>  add hl,de
>  add hl,de
>  add hl,de
>  srl a  ;Do x/8
>  srl a
>  srl a
>  ld d,0
>  ld e,a
>  add hl,de
>  ld de,8e29
>  add hl,de
>  ld b,00000111b
>  and b
>  cp 0 ;checks if sprite is aligned
>  jr z,Aligned_Sprite ;If so, goto aligned sprite bit
> ;********Non-aligned sprite blit starts here********
>  ld b,a  ;Shift counter
>  ld c,8  ;Line counter
> Line_Loop:
>  ld d,(ix+0)
>  push bc
> Shift_Loop:
>  srl d
>  rr e
>  djnz Shift_Loop
>  pop bc
>  ld a,d  ;Write line to graphbuf
>  xor (hl)
>  ld (hl),a
>  inc hl
>  ld a,e
>  xor (hl)
>  ld (hl),a
>  ld de,11
>  add hl,de
>  inc ix
>  dec c
>  jr nz,Line_Loop
>  ret
> ;********Aligned sprite blit starts here********
> Aligned_Sprite:
>  ld c,16  ;Line counter
> Aligned_Loop:
>  ld d,(ix+0)
>  ld a,d
>  xor (hl)
>  ld (hl),a
>  ld de,12
>  add hl,de
>  inc ix
>  dec c
>  jr nz,Aligned_Loop
>  ret
> .end
> END
>
> If anyone can find what I did wrong, I'd really appreciate it. Thanx.
> --
> Pizza of Hut
> http://www.antishrine.sacone.com/
>
>
>
>

References:

A83: Sprite routine problems

From: Pizza of Hut <pizzaofhut@geocities.com>