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|
.scope Print
;; Print a "Please wait..." message to the screen. This message will be centered
;; horizontally and slightly at the top of the screen. This function assumes
;; that alphanumerical tiles are located in a similar fashion as for the
;; `assets/alphanum.chr` file.
.proc show_wait_message
WRITE_PPU_DATA $2129, $2A
WRITE_PPU_DATA $212A, $26
WRITE_PPU_DATA $212B, $1F
WRITE_PPU_DATA $212C, $1B
WRITE_PPU_DATA $212D, $2D
WRITE_PPU_DATA $212E, $1F
WRITE_PPU_DATA $2130, $31
WRITE_PPU_DATA $2131, $1B
WRITE_PPU_DATA $2132, $23
WRITE_PPU_DATA $2133, $2E
WRITE_PPU_DATA $2134, $36
WRITE_PPU_DATA $2135, $36
WRITE_PPU_DATA $2136, $36
rts
.endproc
;; TODO
.proc show_bcd_16_number
;; Clear tiles that were written by `show_wait_message` and that are not re-used
;; here.
WRITE_PPU_DATA $2129, $00
WRITE_PPU_DATA $212A, $00
WRITE_PPU_DATA $212B, $00
WRITE_PPU_DATA $212C, $00
WRITE_PPU_DATA $212D, $00
WRITE_PPU_DATA $2133, $00
WRITE_PPU_DATA $2134, $00
WRITE_PPU_DATA $2135, $00
WRITE_PPU_DATA $2136, $00
;; And loop so PPU::ADDRESS $2E21-$2E32 has the data as stored on bcdResult,
;; which is the binary to decimal conversion result when the final
;; computation was done.
ldx #4
ldy #$2E
@loop:
;; PPU address.
bit PPU::STATUS
lda #$21
sta PPU::ADDRESS
sty PPU::ADDRESS
;; PPU data.
lda bcdResult, x
clc
adc #$10
sta PPU::DATA
dex
iny
cpy #$33
bne @loop
rts
.endproc
;; Copies basic palettes into the proper PPU address.
.proc load_basic_palettes
PPU_ADDR $3F00
ldx #0
@load_palettes_loop:
lda palettes, x
sta PPU::DATA
inx
cpx #$20
bne @load_palettes_loop
rts
palettes:
;; Background (only first one used)
.byte $0F, $30, $10, $00
.byte $0F, $00, $00, $00
.byte $0F, $00, $00, $00
.byte $0F, $00, $00, $00
;; Foreground (unused)
.byte $0F, $00, $00, $00
.byte $0F, $00, $00, $00
.byte $0F, $00, $00, $00
.byte $0F, $00, $00, $00
.endproc
.endscope
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