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SPO600 - Lab 4 - Option 2
source link: https://dev.to/tcvan0707/spo600-lab-4-option-2-5fkn
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In order to continue with the last lab, this time I choose another option to implement, which is Screen Colour Selector.
Instruction
- Create a subroutine which displays on the character display a list of colours available on the bitmapped display, one colour per line, with one of the colours names highlighted in reverse (white or black). The user may use the up/down arrow keys to change the highlighted row. Return the user's selection as a number in the accumulator register when they press Enter.
- Using this subroutine, get a colour from the user, then fill the bitmap display with this colour, and allow the user to select a different colour.
Program
; ROM ROUTINES
define SCINIT $ff81 ; initialize/clear screen
define CHROUT $ffd2 ; output character to screen
; DECLARES VARIABLES
define COLOUR $10
define COLOUR_INDEX $11
define POINTER $40
define POINTER_H $41
define UP_KEY $80
define DOWN_KEY $82
; BASE INITIALIZE
lda #$00
sta COLOUR
sta COLOUR_INDEX
jsr initializePrint
; GET INPUT BY UP/DOWN ARROW KEYS
getKey:
lda $ff
sty $ff
cmp #UP_KEY
beq decrementKey
cmp #DOWN_KEY
beq incrementKey
jmp getKey
decrementKey:
lda COLOUR
cmp #$01
bpl decrementColour
jmp getKey
decrementColour:
dec COLOUR
jsr initializePrint
jsr initializePaint
jmp getKey
incrementKey:
lda COLOUR
cmp #$0f
bmi incrementColour
jmp getKey
incrementColour:
inc COLOUR
jsr initializePrint
jsr initializePaint
jmp getKey
; PRINT OUT SCREEN
initializePrint:
jsr SCINIT
ldy #$00
writeTitle:
lda title,y
beq titleDone
jsr CHROUT
iny
bne writeTitle
titleDone:
lda #$00
sta COLOUR_INDEX
startColour:
ora #$00
ldy #$00
colourName:
jsr selectedColour
beq afterWriting
jsr highlightLine
jsr CHROUT
iny
bne colourName
afterWriting:
inc COLOUR_INDEX
lda COLOUR_INDEX
cmp #$10
bne startColour
selectedColour:
lda COLOUR_INDEX
cmp #$00
beq printColour0
cmp #$01
beq printColour1
cmp #$02
beq printColour2
cmp #$03
beq printColour3
cmp #$04
beq printColour4
cmp #$05
beq printColour5
cmp #$06
beq printColour6
cmp #$07
beq printColour7
cmp #$08
beq printColour8
cmp #$09
beq printColour9
cmp #$0a
beq printColour10
cmp #$0b
beq printColour11
cmp #$0c
beq printColour12
cmp #$0d
beq printColour13
cmp #$0e
beq printColour14
cmp #$0f
beq printColour15
rts
printColour0:
lda colour0,y
rts
printColour1:
lda colour1,y
rts
printColour2:
lda colour2,y
rts
printColour3:
lda colour3,y
rts
printColour4:
lda colour4,y
rts
printColour5:
lda colour5,y
rts
printColour6:
lda colour6,y
rts
printColour7:
lda colour7,y
rts
printColour8:
lda colour8,y
rts
printColour9:
lda colour9,y
rts
printColour10:
lda colour10,y
rts
printColour11:
lda colour11,y
rts
printColour12:
lda colour12,y
rts
printColour13:
lda colour13,y
rts
printColour14:
lda colour14,y
rts
printColour15:
lda colour15,y
rts
highlightLine:
ldx COLOUR_INDEX
cpx COLOUR
beq highlight
ora #$00
rts
highlight:
ora #$80
rts
; CHANGE THE COLOUR OF THE BITMAP
initializePaint:
lda #$00 ; set a pointer at $40 to point to $0200
sta POINTER
lda #$02
sta POINTER_H
ldy #$00
lda COLOUR
draw_screen:
sta ($40), y ; set pixel
iny ; increment index
bne draw_screen ; continue until done the page
inc $41 ; increment the page
ldx $41 ; get the page
cpx #$06 ; compare with 6
bne draw_screen ; continue until done all pages
rts
; LIST OF COLOURS DIPLAYS ON SCREEN
title:
dcb "L","i","s","t",32,"o","f",32,"C","o","l","o","u","r","s",":",13
dcb 00
colour0:
dcb "B","l","a","c","k",13
dcb 00
colour1:
dcb "W","h","i","t","e",13
dcb 00
colour2:
dcb "R","e","d",13
dcb 00
colour3:
dcb "C","y","a","n",13
dcb 00
colour4:
dcb "P","u","r","p","l","e",13
dcb 00
colour5:
dcb "G","r","e","e","n",13
dcb 00
colour6:
dcb "B","l","u","e",13
dcb 00
colour7:
dcb "Y","e","l","l","o","w",13
dcb 00
colour8:
dcb "O","r","a","n","g","e",13
dcb 00
colour9:
dcb "B","r","o","w","n",13
dcb 00
colour10:
dcb "L","i","g","h","t",32,"r","e","d",13
dcb 00
colour11:
dcb "D","a","r","k",32,"g","r","e","y",13
dcb 00
colour12:
dcb "G","r","e","y",13
dcb 00
colour13:
dcb "L","i","g","h","t",32,"g","r","e","e","n",13
dcb 00
colour14:
dcb "L","i","g","h","t",32,"b","l","u","e",13
dcb 00
colour15:
dcb "L","i","g","h","t",32,"g","r","e","y",13
dcb 00
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What I have learned from this lab?
I realize that it is not easy to work with string in Assembly Language. I have encountered a lots of errors when working with string as well as sub routines. Finally, I have come up with my program, even though not exactly as I expected, but I am happy because it works.
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