A86: Stupid program

To: assembly-86@lists.ticalc.org
Subject: A86: Stupid program
From: Tercero <tercero@busprod.com>
Date: Thu, 23 Jul 1998 12:11:08 -0700
Delivered-To: assembly-86-outgoing@towerguard.unix.edu.sollentuna.se
Organization: BPS Internet
Reply-To: assembly-86@lists.ticalc.org

It's not like me to ask for help but now I'm desperate.

The purpose of the enclosed program is to display this
cute little guy on the screen and be able to smooth scroll
him around.  The display part works the smooth scroll doesn't
would someone please help me?

-- 
Tercero	 --  Email: mailto:tercero@busprod.com

"The stone the builders rejected has become the capstone;"
			--Psalms 118:22
"Everyone who falls on that stone will be broken to pieces,
but he on whom it falls will be crushed."
			--Luke 20:18

#include "asm86.h"
#include "ti86asm.inc"

.org _asm_exec_ram

Initialization:
	call _clrLCD	; clear the screen
	ld bc, $0101    ; pic position pointer
	ld ix, Down	; load the pic
	call PutSprite	; disp the pic

Waitkey:
	call _getkey	; look for keys
	nop		; take 5 for the batteries
	nop		; <inhale>
	nop		; <exhale>
	nop		; <inhale>
	nop		; <exhale>
	cp kExit	; Exit ?
	ret z		; Exit !
	cp kUp		; Is Up pressed?
	jp z, MUp	; Go there
	cp kDown	; blah
	jp z, MDown	; blah
	cp kLeft	; blag (oops)
	jp z, MLeft
	cp kRight
	jp z, MRight
	jp Waitkey	; no keys pressed? do it again!

MUp:
	ld ix, Down	; load the pic
	call PutSprite	; erase old pic
	dec c		; move pic position
	ld ix, Down	; ld pic
	call PutSprite	; disp new pic
	jp Waitkey	; do it again and again and again
MLeft:
	ld ix, Down	; come on the procedure is the same
	call PutSprite	; for the rest of the program
	dec b
	ld ix, Down
	call PutSprite
	jp Waitkey
MRight:
	ld ix, Down
	call PutSprite
	inc b
	ld ix, Down
	call PutSprite
	jp Waitkey
MDown:
	ld ix, Down
	call PutSprite
	inc c
	ld ix, Down
	call PutSprite
	jp Waitkey

Down:   .db %00111110,%01010101,%01010101,%01000001
	.db %00111110,%01001001,%00110110,%00000000

;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 and de destroyed

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 byte of the sprite
 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 (if you changed the first)
 ld (hl),a
 ld a,15                        ;add 15 to hl (now 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