Re: A86: Erasing Old Sprites

To: assembly-86@lists.ticalc.org
Subject: Re: A86: Erasing Old Sprites
From: GrafixxHQ@aol.com
Date: Mon, 31 Aug 1998 20:34:49 EDT
Delivered-To: assembly-86-outgoing@towerguard.unix.edu.sollentuna.se
Reply-To: assembly-86@lists.ticalc.org

In a message dated 8/31/98 7:15:24 PM Central Daylight Time, diddy@apci.net
writes:

<< Here is the code.
 
 Thanks
  >>

I fixed it!!!! 
I tried to comment what I could, but if you have any questions, go ahead and
ask!

;***********************************
;*Move The Dude V 0.2.10 Build ????*
;***********************************
;*This Program Should Move The Dude*
;*Except It Doesn't... But It Will!*
;*Also This Is My First ASM Program*
;***********************************
;*Programming:  Super Llama        *
:*GFX: Super Llama                 *
;***********************************
;*       Known Bugs In Game:       *
;***********************************
;*1. Will Not Move More Than 3     *
;*   Spaces Left Or Right.         *
;*2. Does Not Correctly Erase Old  *
;*   Dude And Put Up The New One.  *
;*3. Only Erases If You Move       *
;*   Backwards.                    *
;***********************************

#include "asm86.h"	   ;ASM 86 Include File
#include "ti86asm.inc"     ;TI's Include File

.org _asm_exec_ram         ;Starting Point
    call _clrLCD           ;Clears The LCD
    call BUSY_OFF          ;Turns Off Run Thingy
    jr Setup               ;Goto Setup


Setup:
    ld b,0                 ;Loads 0 As Y-Coordinate
    ld c,0                 ;Loads 0 As X-Coordinate
    ld ix,0                ;Clears Image Bank
    ld ix,Dude             ;Loads Dude As Sprite
	push bc				;****Save the coordinates
    call PutSprite         ;Run PutSprite Routine

Move:
    call GET_KEY           ;Getkey Function
    cp K_EXIT              ;Is It Exit
    jr z,Exit              ;Then Goto Exit
    cp K_UP                ;Is It Up
    jr z,Up                ;Then Goto Up
    cp K_DOWN              ;Is It Down
    jr z,Down              ;Then Goto Down
    cp K_LEFT              ;Is It Left
    jr z,Left              ;Then Goto Left
    cp K_RIGHT             ;Is It Right
    jr z,Right             ;Then Goto Right
    jr Move                ;If None Try Again

Up:
	pop bc					;****get back coords (incase something messed it up)
	call ClearOld			;****Clear the old and put the new
    ld a,c                 ;Load C Into A
    sub 8                  ;Subtract 8 From A
    ld c,a                 ;Load A Into C
	push bc					;****save bc again
    jp DrawNew             ;Goto DrawNew

Down:
	pop bc					;same as above
	call ClearOld			;****Clear the old and put the new
    ld a,c                 ;Load C Into A
    add a,8                ;Add 8 To A
    ld c,a                 ;Load A Into C
	push bc					;same as above
    jp DrawNew             ;Goto DrawNew

Left:
	pop bc					;same as above
	call ClearOld			;****Clear the old and put the new
    ld a,b                 ;Load B Into A
    sub 8                  ;Subtract 8 From A
    ld b,a                 ;Load A Into B
	push bc					;same as above
    jp DrawNew             ;Goto DrawNew

Right:
	pop	bc					;same as above
	call ClearOld			;****Clear the old and put the new              
    ld a,b                 ;Load B Into A
    add a,8                ;Add 8 To A
    ld b,a                 ;Load A Into B
	push bc					;same as above
    jp DrawNew             ;Goto DrawNew

Exit:
	pop bc				;***have to pop what has been pushed at the end
    call _clrLCD           ;Clear The LCD
    ret                    ;End Program

ClearOld:
		;removed ld b,b  (b is already b)
    ld ix,0                ;Flush Image Bank
    ld ix,Dude            ;Load Clear As Image
    call PutSprite         ;Run PutSprite Routine
    ret                ;changed so you can call this

DrawNew:
    ld ix,0                ;Flush Image bank
    ld ix,Dude             ;Load Dude As Image
    call PutSprite         ;Run PutSprite Routine
    jp Move                ;Goto Move


;************************************************
;*                  PutSprite                   *
;************************************************
;*Input: BC = X,Y; IX = 8x8 Sprite Location     *
;*Output: Sprite Drawn; IX Points To Next Sprite*
;*If Your Sprites Follow In Sequence            *
;*HL And DE Are Destroyed                       *
;************************************************
;*Disclaimer: I Did Not Write This Routine!!!   *
;************************************************

PutSprite:
    ld h,63	           ;Shifted To $FC With Add HL,HL
    ld a,c
    add a,a	           ;A*4
    add a,a
    ld l,a
    add hl,hl              ;HL*4 (What Was C Has Been MLT By 16)
    add hl,hl
    ld a,b                 ;A/8
    rra
    rra
    rra
    or l	           ;Add To More Significant Bytes
    ld l,a
    ld a,7	           ;Use Bottom 7 Bits For Counter
    and b
    ld d,a	           ;Save Counter Copy In D
    ld e,8	           ;8 Rows
    push bc

ps_loop:
    ld b,d	           ;Get Saved Bit Offset In B
    ld a,(ix)	           ;Get This Byte Of The Sprite In A
    inc ix                 ;Point IX To The Next Sprite Byte
    ld c,0
    call bit_shift
    xor (hl)	           ;Change This To OR If You Want
    ld (hl),a
    inc l
    ld a,(hl)
    xor c	           ;Also Changable To OR
    ld (hl),a
    ld a,15	           ;Add 15 To HL (Ready For Next Row)
    call add_hl_a
    dec e                  ;Counter (8 Rows)
    jr nz,ps_loop
    pop bc
    ret

add_hl_a:	           ;Add HL,A
    add a,l
    ld l,a
    ret nc
    inc h
    ret

bit_shift:	           ;While(B=<0)
    dec b	           ;A>>C
    ret m
    srl a
    rr c
    jr bit_shift           ;End PutSprite Routine

;*****************
;*  The Sprites  *
;*****************

Dude:			
.db %01110000              ;Start Sprite Code
.db %01110000
.db %00100000
.db %00100100
.db %01111110
.db %00110100
.db %00111000
.db %01101100              ;End Sprite Code

;Don't need Clear anymore

.end                       ;End ASM Code
.end                       ;Make Sure Compiler Understands