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STARS.ASM
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STARS.ASM
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;+----------
;| Cheesy Side Scrolling Stars
;|
#include "ti-85.h"
#include "tidefs.h"
max_x = 128
max_y = 64
ArrayStart = $80DF ; Table Of Data for 'Stars'
; Stored as X, then Y,
; Then next Star... 10 stars?
; room for 84 stars
TIMER = $8008
.org 0
.db "Stars",0
ProgStart:
ROM_CALL(CLEARLCD)
;ld a,4 ;mem page 4
;out (5),a ;for graphics
;CALL_(SetUpStars)
;CALL_(DrawStars)
CALL_(GetRandom)
ld hl, 0
ld l,a
ld (text_x),a
ld (text_y),a
CALL_(D_HL_DECI)
CALL_(WaitKey)
ExitMain:
ret
;+----
;| Set Up Stars...
;+----
SetUpStars:
ld b, 20
ld hl, ArrayStart
SUSLoop:
push bc
CALL_(GetRandom)
ld (hl),a ; x = rand between 0-127
inc hl
CALL_(GetRandom)
sra a
ld (hl),a ; y = rand between 0-63
inc hl
pop bc
djnz SUSLoop
SUSExit:
ret
;+----
;| Get Random Number (Uses Blink Timer) / A = Random Number
;+----
GetRandom:
push hl
ld hl, timer
ld a, (hl)
pop hl
ret
;+----
;| Draw Stars...
;+----
DrawStars:
ld a,4 ;mem page 4
out (5),a ;for graphics
ld b,20
DSLoop:
push bc
ld b,(hl)
inc hl
ld c,(hl)
inc hl
CALL_(PutPixel)
pop bc
djnz DSLoop
DSExit:
ret
;+----
;| Long Delay
;+----
Long_Delay:
push af
push bc
ld bc,30000
Long_Delay_Loop:
dec bc
ld a,b
or c
jr nz,Long_Delay_Loop
pop bc
pop af
ret
;+----
;| Put Pixel (B,C)
;+----
PutPixel:
push bc ;Save away, so it can be used again
ROM_CALL(FIND_PIXEL) ;Get the pixel offset
ld de,$FC00
add hl,de ;Point into the graphics memory
or (HL) ;A now contains the modified screen byte
ld (HL),A ;Write back to screen to update
pop bc ;Restore
ret
;+----
;| Erase Pixel At (B,C)
;+----
DelPixel:
push bc ;Save away, so it can be used again
ROM_CALL(FIND_PIXEL) ;Get the pixel offset
ld de,$FC00
add hl,de ;Point into graphics memory
xor 255 ;Invert the accumulator
and (hl) ;A now contains the modified screen byte
ld (hl),a ;Write back to screen to update
pop bc ;Restore
ret
;+----
;| Get Pixel At (B,C)
;+----
GetPixel:
push bc ;Store away, so it can be used again
ROM_CALL(FIND_PIXEL) ;Get the pixel offset
ld de,$FC00
add hl,de ;Point into graphics memory
and (hl) ;ACC is ACC AND the memory
pop bc ;Restore
ret
;+----
;| Wait For Key Press
;+----
WaitKey:
call get_key
cp K_NOKEY
jr z, WaitKey
ret
.end