GSCats/smallNumbers.s

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; Mini font render dedicated to small numbers.
; Adapted from Dagen Brock's general purpose font
; engine, also in this project
;
; A= ptr to string preceded by length
; X= screen location
; Trashes zero page locations 6,7
;
F_LEN: .word 0 ;length of string (only one byte currently used)
F_DIGITIDX: .word 0 ;index of current character
F_CURRPOS: .word 0 ;current top left char position
F_NUMPTR = $06 ;pointer to string (including length byte) / DP
DrawTinyNumber:
SAVE_AXY
sta F_NUMPTR
stx F_CURRPOS
stz F_DIGITIDX
lda (F_NUMPTR)
and #$00ff ;strip off first char (len is only one byte)
sta F_LEN ;get our length byte
nextDigit:
lda F_DIGITIDX
cmp F_LEN
bne moreDigits
RESTORE_AXY
rts
moreDigits:
inc F_DIGITIDX
ldy F_DIGITIDX
lda (F_NUMPTR),y ;get next char!
and #$00FF ;mask high byte
sec
sbc #'0' ;our table starts with space ' '
asl
tay
ldx F_CURRPOS
jsr drawDigit
inc F_CURRPOS
inc F_CURRPOS ;update screen pos (1 word=4 pixels)
bra nextDigit
;x = TopLeft screen pos
;y = char table offset
drawDigit:
lda DigitTable,y ;get real address of char data
sec
sbc #DigitData ;pivot offset - now a is offset of fontdata
tay ;so we'll index with that
lda DigitData,y
sta $012000,x
lda DigitData+2,y
sta $012000+160,x
lda DigitData+4,y
sta $012000+160*2,x
lda DigitData+6,y
sta $012000+160*3,x
lda DigitData+8,y
sta $012000+160*4,x
rts
DigitTable:
.addr s_0
.addr s_1
.addr s_2
.addr s_3
.addr s_4
.addr s_5
.addr s_6
.addr s_7
.addr s_8
.addr s_9
.addr s_SmallDollar ; Use ASCII code for colon
DigitData:
s_0:
fontword $FFF0
fontword $F0F0
fontword $F0F0
fontword $F0F0
fontword $FFF0
s_1:
fontword $0F00
fontword $FF00
fontword $0F00
fontword $0F00
fontword $0F00
s_2:
fontword $FFF0
fontword $00F0
fontword $FFF0
fontword $F000
fontword $FFF0
s_3:
fontword $FFF0
fontword $00F0
fontword $FFF0
fontword $00F0
fontword $FFF0
s_4:
fontword $F0F0
fontword $F0F0
fontword $FFF0
fontword $00F0
fontword $00F0
s_5:
fontword $FFF0
fontword $F000
fontword $FFF0
fontword $00F0
fontword $FFF0
s_6:
fontword $FFF0
fontword $F000
fontword $FFF0
fontword $F0F0
fontword $FFF0
s_7:
fontword $FFF0
fontword $00F0
fontword $00F0
fontword $00F0
fontword $00F0
s_8:
fontword $FFF0
fontword $F0F0
fontword $FFF0
fontword $F0F0
fontword $FFF0
s_9:
fontword $FFF0
fontword $F0F0
fontword $FFF0
fontword $00F0
fontword $00F0
s_SmallDollar: ; Use ASCII code for colon
.dbyt $a66a
.dbyt $6F66
.dbyt $6666
.dbyt $a66a
.dbyt $aaaa