EDASS-128-RASTER-BARS-MANDATORY-LIKE-Hello-World!
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TOOL: 		EDASS-128 {Commodore C128 EDITOR & ASSEMBLER}
Language: 	Assembler 
Extra:		-
Author: 	Misel Zivanovic
Note:		(C) 8th FEB 2026  - www.lived.ch, mzretro.ch
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Raster bars is something everyone wanted to do as a kid, no doubt.
On the internet you can find tons of different approaches and here is my way to do it.

Main goal was to achieve stability without involving everything possible!

I think it's a well done job!

I used jsr $ffd2 KERNAL routine to show text, but positioning isn't so the strength
of it... Could be that there is another, better, more byte-efficient way?
STA to be better choice in such cases where you need to position more than one line of text
on the screen.  

Whatever, it's doing its job for now. Won't bother any longer for now with this.


rasterbars.asm     -a:0010-a:    -e:

;--------------------------------------
         *=  $1300
         .obj m
         .bank 15
;--------------------------------------
;
;
         lda #147      ;clear screen
         jsr $ffd2     ;
;        lda #22       ;lowercase map
;        sta $a2c
;
         jsr gotext
;
 start   jsr $ffe4
         cmp #$0d      ;hold enter >quit
         beq basic
         ldx #$00
         ldy #48       ;start position
 cycle   lda color,x
 go      cpy $d012
         bne go
         sta $d020
         sta $d021
         inx
         iny
         iny
         iny
         iny
         iny
         iny
         iny
         iny
         iny
         iny
         iny
         iny
         iny
         iny
         cpx #16
         bne cycle
         jmp start     ;and repeat
;
 basic   lda #$0c      ;exit settings
         sta $d020
         lda #$0b
         sta $d021
         lda #$0f
         sta $f1
;        lda #$14      ;uppercase map
;        sta $a2c
         rts
;
;--------------------------------------
;        show text
;--------------------------------------
 gotext  lda #$00
         sta $f1       ; text color
         clc
         ldx #12
         ldy #10
         jsr $c018
         ldx #$00
 line1   lda text1,x   ;text line 1
         jsr $ffd2
         inx
         cpx #16
         bne line1
         clc
         ldx #20
         ldy #10
         jsr $c018
         ldx #$00
 line2   lda text2,x   ;text line 2
         jsr $ffd2
         inx
         cpx #16
         bne line2
         rts
;--------------------------------------
 color   .byte $01,$02,$03,$04,$05,$06
         .byte $07,$08,$09,$0a,$0b,$0c
         .byte $0e,$0d,$0f,$00
 text1   .text "C128 Color Bars!"
 text2   .text "Press ENTER=QUIT"