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prog8/compiler/res/prog8lib/c64utils.p8

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; Prog8 definitions for the Commodore-64
; These are the utility subroutines.
;
; Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
;
; indent format: TABS, size=8
%import c64lib
c64utils {
; ----- number conversions to decimal strings
asmsub ubyte2decimal (ubyte value @ A) -> ubyte @ Y, ubyte @ A, ubyte @ X {
; ---- A to decimal string in Y/A/X (100s in Y, 10s in A, 1s in X)
%asm {{
ldy #uword2decimal.ASCII_0_OFFSET
bne uword2decimal.hex_try200
rts
}}
}
asmsub uword2decimal (uword value @ AY) -> ubyte @Y, ubyte @A, ubyte @X {
; ---- convert 16 bit uword in A/Y to decimal
; output in uword2decimal.decTenThousands, decThousands, decHundreds, decTens, decOnes
; (these are terminated by a zero byte so they can be easily printed)
; also returns Y = 100's, A = 10's, X = 1's
%asm {{
;Convert 16 bit Hex to Decimal (0-65535) Rev 2
;By Omegamatrix Further optimizations by tepples
; routine from http://forums.nesdev.com/viewtopic.php?f=2&t=11341&start=15
;HexToDec99
; start in A
; end with A = 10's, decOnes (also in X)
;HexToDec255
; start in A
; end with Y = 100's, A = 10's, decOnes (also in X)
;HexToDec999
; start with A = high byte, Y = low byte
; end with Y = 100's, A = 10's, decOnes (also in X)
; requires 1 extra temp register on top of decOnes, could combine
; these two if HexToDec65535 was eliminated...
;HexToDec65535
; start with A/Y (low/high) as 16 bit value
; end with decTenThousand, decThousand, Y = 100's, A = 10's, decOnes (also in X)
; (irmen: I store Y and A in decHundreds and decTens too, so all of it can be easily printed)
ASCII_0_OFFSET = $30
temp = P8ZP_SCRATCH_B1 ; byte in zeropage
hexHigh = P8ZP_SCRATCH_W1 ; byte in zeropage
hexLow = P8ZP_SCRATCH_W1+1 ; byte in zeropage
HexToDec65535; SUBROUTINE
sty hexHigh ;3 @9
sta hexLow ;3 @12
tya
tax ;2 @14
lsr a ;2 @16
lsr a ;2 @18 integer divide 1024 (result 0-63)
cpx #$A7 ;2 @20 account for overflow of multiplying 24 from 43,000 ($A7F8) onward,
adc #1 ;2 @22 we can just round it to $A700, and the divide by 1024 is fine...
;at this point we have a number 1-65 that we have to times by 24,
;add to original sum, and Mod 1024 to get a remainder 0-999
sta temp ;3 @25
asl a ;2 @27
adc temp ;3 @30 x3
tay ;2 @32
lsr a ;2 @34
lsr a ;2 @36
lsr a ;2 @38
lsr a ;2 @40
lsr a ;2 @42
tax ;2 @44
tya ;2 @46
asl a ;2 @48
asl a ;2 @50
asl a ;2 @52
clc ;2 @54
adc hexLow ;3 @57
sta hexLow ;3 @60
txa ;2 @62
adc hexHigh ;3 @65
sta hexHigh ;3 @68
ror a ;2 @70
lsr a ;2 @72
tay ;2 @74 integer divide 1,000 (result 0-65)
lsr a ;2 @76 split the 1,000 and 10,000 digit
tax ;2 @78
lda ShiftedBcdTab,x ;4 @82
tax ;2 @84
rol a ;2 @86
and #$0F ;2 @88
ora #ASCII_0_OFFSET
sta decThousands ;3 @91
txa ;2 @93
lsr a ;2 @95
lsr a ;2 @97
lsr a ;2 @99
ora #ASCII_0_OFFSET
sta decTenThousands ;3 @102
lda hexLow ;3 @105
cpy temp ;3 @108
bmi _doSubtract ;2³ @110/111
beq _useZero ;2³ @112/113
adc #23 + 24 ;2 @114
_doSubtract
sbc #23 ;2 @116
sta hexLow ;3 @119
_useZero
lda hexHigh ;3 @122
sbc #0 ;2 @124
Start100s
and #$03 ;2 @126
tax ;2 @128 0,1,2,3
cmp #2 ;2 @130
rol a ;2 @132 0,2,5,7
ora #ASCII_0_OFFSET
tay ;2 @134 Y = Hundreds digit
lda hexLow ;3 @137
adc Mod100Tab,x ;4 @141 adding remainder of 256, 512, and 256+512 (all mod 100)
bcs hex_doSub200 ;2³ @143/144
hex_try200
cmp #200 ;2 @145
bcc hex_try100 ;2³ @147/148
hex_doSub200
iny ;2 @149
iny ;2 @151
sbc #200 ;2 @153
hex_try100
cmp #100 ;2 @155
bcc HexToDec99 ;2³ @157/158
iny ;2 @159
sbc #100 ;2 @161
HexToDec99; SUBROUTINE
lsr a ;2 @163
tax ;2 @165
lda ShiftedBcdTab,x ;4 @169
tax ;2 @171
rol a ;2 @173
and #$0F ;2 @175
ora #ASCII_0_OFFSET
sta decOnes ;3 @178
txa ;2 @180
lsr a ;2 @182
lsr a ;2 @184
lsr a ;2 @186
ora #ASCII_0_OFFSET
; irmen: load X with ones, and store Y and A too, for easy printing afterwards
sty decHundreds
sta decTens
ldx decOnes
rts ;6 @192 Y=hundreds, A = tens digit, X=ones digit
HexToDec999; SUBROUTINE
sty hexLow ;3 @9
jmp Start100s ;3 @12
Mod100Tab
.byte 0,56,12,56+12
ShiftedBcdTab
.byte $00,$01,$02,$03,$04,$08,$09,$0A,$0B,$0C
.byte $10,$11,$12,$13,$14,$18,$19,$1A,$1B,$1C
.byte $20,$21,$22,$23,$24,$28,$29,$2A,$2B,$2C
.byte $30,$31,$32,$33,$34,$38,$39,$3A,$3B,$3C
.byte $40,$41,$42,$43,$44,$48,$49,$4A,$4B,$4C
decTenThousands .byte 0
decThousands .byte 0
decHundreds .byte 0
decTens .byte 0
decOnes .byte 0
.byte 0 ; zero-terminate the decimal output string
}}
}
; ----- utility functions ----
asmsub byte2decimal (byte value @ A) -> ubyte @ Y, ubyte @ A, ubyte @ X {
; ---- A (signed byte) to decimal string in Y/A/X (100s in Y, 10s in A, 1s in X)
; note: if the number is negative, you have to deal with the '-' yourself!
%asm {{
cmp #0
bpl +
eor #255
clc
adc #1
+ jmp ubyte2decimal
}}
}
asmsub ubyte2hex (ubyte value @ A) -> ubyte @ A, ubyte @ Y {
; ---- A to hex petscii string in AY (first hex char in A, second hex char in Y)
%asm {{
stx P8ZP_SCRATCH_REG_X
pha
and #$0f
tax
ldy _hex_digits,x
pla
lsr a
lsr a
lsr a
lsr a
tax
lda _hex_digits,x
ldx P8ZP_SCRATCH_REG_X
rts
_hex_digits .text "0123456789abcdef" ; can probably be reused for other stuff as well
}}
}
asmsub uword2hex (uword value @ AY) clobbers(A,Y) {
; ---- convert 16 bit uword in A/Y into 4-character hexadecimal string 'uword2hex.output' (0-terminated)
%asm {{
sta P8ZP_SCRATCH_REG
tya
jsr ubyte2hex
sta output
sty output+1
lda P8ZP_SCRATCH_REG
jsr ubyte2hex
sta output+2
sty output+3
rts
output .text "0000", $00 ; 0-terminated output buffer (to make printing easier)
}}
}
asmsub str2uword(str string @ AY) -> uword @ AY {
; -- returns the unsigned word value of the string number argument in AY
; the number may NOT be preceded by a + sign and may NOT contain spaces
; (any non-digit character will terminate the number string that is parsed)
%asm {{
_result = P8ZP_SCRATCH_W2
sta _mod+1
sty _mod+2
ldy #0
sty _result
sty _result+1
_mod lda $ffff,y ; modified
sec
sbc #48
bpl +
_done ; return result
lda _result
ldy _result+1
rts
+ cmp #10
bcs _done
; add digit to result
pha
jsr _result_times_10
pla
clc
adc _result
sta _result
bcc +
inc _result+1
+ iny
bne _mod
; never reached
_result_times_10 ; (W*4 + W)*2
lda _result+1
sta P8ZP_SCRATCH_REG
lda _result
asl a
rol P8ZP_SCRATCH_REG
asl a
rol P8ZP_SCRATCH_REG
clc
adc _result
sta _result
lda P8ZP_SCRATCH_REG
adc _result+1
asl _result
rol a
sta _result+1
rts
}}
}
asmsub str2word(str string @ AY) -> word @ AY {
; -- returns the signed word value of the string number argument in AY
; the number may be preceded by a + or - sign but may NOT contain spaces
; (any non-digit character will terminate the number string that is parsed)
%asm {{
_result = P8ZP_SCRATCH_W2
sta P8ZP_SCRATCH_W1
sty P8ZP_SCRATCH_W1+1
ldy #0
sty _result
sty _result+1
sty _negative
lda (P8ZP_SCRATCH_W1),y
cmp #'+'
bne +
iny
+ cmp #'-'
bne _parse
inc _negative
iny
_parse lda (P8ZP_SCRATCH_W1),y
sec
sbc #48
bpl _digit
_done ; return result
lda _negative
beq +
sec
lda #0
sbc _result
sta _result
lda #0
sbc _result+1
sta _result+1
+ lda _result
ldy _result+1
rts
_digit cmp #10
bcs _done
; add digit to result
pha
jsr str2uword._result_times_10
pla
clc
adc _result
sta _result
bcc +
inc _result+1
+ iny
bne _parse
; never reached
_negative .byte 0
}}
}
asmsub set_irqvec_excl() clobbers(A) {
%asm {{
sei
lda #<_irq_handler
sta c64.CINV
lda #>_irq_handler
sta c64.CINV+1
cli
rts
_irq_handler jsr set_irqvec._irq_handler_init
jsr irq.irq
jsr set_irqvec._irq_handler_end
lda #$ff
sta c64.VICIRQ ; acknowledge raster irq
lda c64.CIA1ICR ; acknowledge CIA1 interrupt
jmp c64.IRQDFEND ; end irq processing - don't call kernel
}}
}
asmsub set_irqvec() clobbers(A) {
%asm {{
sei
lda #<_irq_handler
sta c64.CINV
lda #>_irq_handler
sta c64.CINV+1
cli
rts
_irq_handler jsr _irq_handler_init
jsr irq.irq
jsr _irq_handler_end
jmp c64.IRQDFRT ; continue with normal kernel irq routine
_irq_handler_init
; save all zp scratch registers and the X register as these might be clobbered by the irq routine
stx IRQ_X_REG
lda P8ZP_SCRATCH_B1
sta IRQ_SCRATCH_ZPB1
lda P8ZP_SCRATCH_REG
sta IRQ_SCRATCH_ZPREG
lda P8ZP_SCRATCH_REG_X
sta IRQ_SCRATCH_ZPREGX
lda P8ZP_SCRATCH_W1
sta IRQ_SCRATCH_ZPWORD1
lda P8ZP_SCRATCH_W1+1
sta IRQ_SCRATCH_ZPWORD1+1
lda P8ZP_SCRATCH_W2
sta IRQ_SCRATCH_ZPWORD2
lda P8ZP_SCRATCH_W2+1
sta IRQ_SCRATCH_ZPWORD2+1
; stack protector; make sure we don't clobber the top of the evaluation stack
dex
dex
dex
dex
dex
dex
cld
rts
_irq_handler_end
; restore all zp scratch registers and the X register
lda IRQ_SCRATCH_ZPB1
sta P8ZP_SCRATCH_B1
lda IRQ_SCRATCH_ZPREG
sta P8ZP_SCRATCH_REG
lda IRQ_SCRATCH_ZPREGX
sta P8ZP_SCRATCH_REG_X
lda IRQ_SCRATCH_ZPWORD1
sta P8ZP_SCRATCH_W1
lda IRQ_SCRATCH_ZPWORD1+1
sta P8ZP_SCRATCH_W1+1
lda IRQ_SCRATCH_ZPWORD2
sta P8ZP_SCRATCH_W2
lda IRQ_SCRATCH_ZPWORD2+1
sta P8ZP_SCRATCH_W2+1
ldx IRQ_X_REG
rts
IRQ_X_REG .byte 0
IRQ_SCRATCH_ZPB1 .byte 0
IRQ_SCRATCH_ZPREG .byte 0
IRQ_SCRATCH_ZPREGX .byte 0
IRQ_SCRATCH_ZPWORD1 .word 0
IRQ_SCRATCH_ZPWORD2 .word 0
}}
}
asmsub restore_irqvec() {
%asm {{
sei
lda #<c64.IRQDFRT
sta c64.CINV
lda #>c64.IRQDFRT
sta c64.CINV+1
lda #0
sta c64.IREQMASK ; disable raster irq
lda #%10000001
sta c64.CIA1ICR ; restore CIA1 irq
cli
rts
}}
}
asmsub set_rasterirq(uword rasterpos @ AY) clobbers(A) {
%asm {{
sei
jsr _setup_raster_irq
lda #<_raster_irq_handler
sta c64.CINV
lda #>_raster_irq_handler
sta c64.CINV+1
cli
rts
_raster_irq_handler
jsr set_irqvec._irq_handler_init
jsr irq.irq
jsr set_irqvec._irq_handler_end
lda #$ff
sta c64.VICIRQ ; acknowledge raster irq
jmp c64.IRQDFRT
_setup_raster_irq
pha
lda #%01111111
sta c64.CIA1ICR ; "switch off" interrupts signals from cia-1
sta c64.CIA2ICR ; "switch off" interrupts signals from cia-2
and c64.SCROLY
sta c64.SCROLY ; clear most significant bit of raster position
lda c64.CIA1ICR ; ack previous irq
lda c64.CIA2ICR ; ack previous irq
pla
sta c64.RASTER ; set the raster line number where interrupt should occur
cpy #0
beq +
lda c64.SCROLY
ora #%10000000
sta c64.SCROLY ; set most significant bit of raster position
+ lda #%00000001
sta c64.IREQMASK ;enable raster interrupt signals from vic
rts
}}
}
asmsub set_rasterirq_excl(uword rasterpos @ AY) clobbers(A) {
%asm {{
sei
jsr set_rasterirq._setup_raster_irq
lda #<_raster_irq_handler
sta c64.CINV
lda #>_raster_irq_handler
sta c64.CINV+1
cli
rts
_raster_irq_handler
jsr set_irqvec._irq_handler_init
jsr irq.irq
jsr set_irqvec._irq_handler_end
lda #$ff
sta c64.VICIRQ ; acknowledge raster irq
jmp c64.IRQDFEND ; end irq processing - don't call kernel
}}
}
} ; ------ end of block c64utils
c64scr {
; ---- this block contains (character) Screen and text I/O related functions ----
asmsub clear_screen (ubyte char @ A, ubyte color @ Y) clobbers(A) {
; ---- clear the character screen with the given fill character and character color.
; (assumes screen and color matrix are at their default addresses)
%asm {{
pha
tya
jsr clear_screencolors
pla
jsr clear_screenchars
rts
}}
}
asmsub clear_screenchars (ubyte char @ A) clobbers(Y) {
; ---- clear the character screen with the given fill character (leaves colors)
; (assumes screen matrix is at the default address)
%asm {{
ldy #0
_loop sta c64.Screen,y
sta c64.Screen+$0100,y
sta c64.Screen+$0200,y
sta c64.Screen+$02e8,y
iny
bne _loop
rts
}}
}
asmsub clear_screencolors (ubyte color @ A) clobbers(Y) {
; ---- clear the character screen colors with the given color (leaves characters).
; (assumes color matrix is at the default address)
%asm {{
ldy #0
_loop sta c64.Colors,y
sta c64.Colors+$0100,y
sta c64.Colors+$0200,y
sta c64.Colors+$02e8,y
iny
bne _loop
rts
}}
}
asmsub scroll_left_full (ubyte alsocolors @ Pc) clobbers(A, Y) {
; ---- scroll the whole screen 1 character to the left
; contents of the rightmost column are unchanged, you should clear/refill this yourself
; Carry flag determines if screen color data must be scrolled too
%asm {{
stx P8ZP_SCRATCH_REG_X
bcs +
jmp _scroll_screen
+ ; scroll the color memory
ldx #0
ldy #38
-
.for row=0, row<=24, row+=1
lda c64.Colors + 40*row + 1,x
sta c64.Colors + 40*row,x
.next
inx
dey
bpl -
_scroll_screen ; scroll the screen memory
ldx #0
ldy #38
-
.for row=0, row<=24, row+=1
lda c64.Screen + 40*row + 1,x
sta c64.Screen + 40*row,x
.next
inx
dey
bpl -
ldx P8ZP_SCRATCH_REG_X
rts
}}
}
asmsub scroll_right_full (ubyte alsocolors @ Pc) clobbers(A) {
; ---- scroll the whole screen 1 character to the right
; contents of the leftmost column are unchanged, you should clear/refill this yourself
; Carry flag determines if screen color data must be scrolled too
%asm {{
stx P8ZP_SCRATCH_REG_X
bcs +
jmp _scroll_screen
+ ; scroll the color memory
ldx #38
-
.for row=0, row<=24, row+=1
lda c64.Colors + 40*row + 0,x
sta c64.Colors + 40*row + 1,x
.next
dex
bpl -
_scroll_screen ; scroll the screen memory
ldx #38
-
.for row=0, row<=24, row+=1
lda c64.Screen + 40*row + 0,x
sta c64.Screen + 40*row + 1,x
.next
dex
bpl -
ldx P8ZP_SCRATCH_REG_X
rts
}}
}
asmsub scroll_up_full (ubyte alsocolors @ Pc) clobbers(A) {
; ---- scroll the whole screen 1 character up
; contents of the bottom row are unchanged, you should refill/clear this yourself
; Carry flag determines if screen color data must be scrolled too
%asm {{
stx P8ZP_SCRATCH_REG_X
bcs +
jmp _scroll_screen
+ ; scroll the color memory
ldx #39
-
.for row=1, row<=24, row+=1
lda c64.Colors + 40*row,x
sta c64.Colors + 40*(row-1),x
.next
dex
bpl -
_scroll_screen ; scroll the screen memory
ldx #39
-
.for row=1, row<=24, row+=1
lda c64.Screen + 40*row,x
sta c64.Screen + 40*(row-1),x
.next
dex
bpl -
ldx P8ZP_SCRATCH_REG_X
rts
}}
}
asmsub scroll_down_full (ubyte alsocolors @ Pc) clobbers(A) {
; ---- scroll the whole screen 1 character down
; contents of the top row are unchanged, you should refill/clear this yourself
; Carry flag determines if screen color data must be scrolled too
%asm {{
stx P8ZP_SCRATCH_REG_X
bcs +
jmp _scroll_screen
+ ; scroll the color memory
ldx #39
-
.for row=23, row>=0, row-=1
lda c64.Colors + 40*row,x
sta c64.Colors + 40*(row+1),x
.next
dex
bpl -
_scroll_screen ; scroll the screen memory
ldx #39
-
.for row=23, row>=0, row-=1
lda c64.Screen + 40*row,x
sta c64.Screen + 40*(row+1),x
.next
dex
bpl -
ldx P8ZP_SCRATCH_REG_X
rts
}}
}
asmsub print (str text @ AY) clobbers(A,Y) {
; ---- print null terminated string from A/Y
; note: the compiler contains an optimization that will replace
; a call to this subroutine with a string argument of just one char,
; by just one call to c64.CHROUT of that single char.
%asm {{
sta P8ZP_SCRATCH_B1
sty P8ZP_SCRATCH_REG
ldy #0
- lda (P8ZP_SCRATCH_B1),y
beq +
jsr c64.CHROUT
iny
bne -
+ rts
}}
}
asmsub print_ub0 (ubyte value @ A) clobbers(A,Y) {
; ---- print the ubyte in A in decimal form, with left padding 0s (3 positions total)
%asm {{
stx P8ZP_SCRATCH_REG_X
jsr c64utils.ubyte2decimal
pha
tya
jsr c64.CHROUT
pla
jsr c64.CHROUT
txa
jsr c64.CHROUT
ldx P8ZP_SCRATCH_REG_X
rts
}}
}
asmsub print_ub (ubyte value @ A) clobbers(A,Y) {
; ---- print the ubyte in A in decimal form, without left padding 0s
%asm {{
stx P8ZP_SCRATCH_REG_X
jsr c64utils.ubyte2decimal
_print_byte_digits
pha
cpy #'0'
beq +
tya
jsr c64.CHROUT
pla
jsr c64.CHROUT
jmp _ones
+ pla
cmp #'0'
beq _ones
jsr c64.CHROUT
_ones txa
jsr c64.CHROUT
ldx P8ZP_SCRATCH_REG_X
rts
}}
}
asmsub print_b (byte value @ A) clobbers(A,Y) {
; ---- print the byte in A in decimal form, without left padding 0s
%asm {{
stx P8ZP_SCRATCH_REG_X
pha
cmp #0
bpl +
lda #'-'
jsr c64.CHROUT
+ pla
jsr c64utils.byte2decimal
jsr print_ub._print_byte_digits
ldx P8ZP_SCRATCH_REG_X
rts
}}
}
asmsub print_ubhex (ubyte value @ A, ubyte prefix @ Pc) clobbers(A,Y) {
; ---- print the ubyte in A in hex form (if Carry is set, a radix prefix '$' is printed as well)
%asm {{
stx P8ZP_SCRATCH_REG_X
bcc +
pha
lda #'$'
jsr c64.CHROUT
pla
+ jsr c64utils.ubyte2hex
jsr c64.CHROUT
tya
jsr c64.CHROUT
ldx P8ZP_SCRATCH_REG_X
rts
}}
}
asmsub print_ubbin (ubyte value @ A, ubyte prefix @ Pc) clobbers(A,Y) {
; ---- print the ubyte in A in binary form (if Carry is set, a radix prefix '%' is printed as well)
%asm {{
stx P8ZP_SCRATCH_REG_X
sta P8ZP_SCRATCH_B1
bcc +
lda #'%'
jsr c64.CHROUT
+ ldy #8
- lda #'0'
asl P8ZP_SCRATCH_B1
bcc +
lda #'1'
+ jsr c64.CHROUT
dey
bne -
ldx P8ZP_SCRATCH_REG_X
rts
}}
}
asmsub print_uwbin (uword value @ AY, ubyte prefix @ Pc) clobbers(A,Y) {
; ---- print the uword in A/Y in binary form (if Carry is set, a radix prefix '%' is printed as well)
%asm {{
pha
tya
jsr print_ubbin
pla
clc
jmp print_ubbin
}}
}
asmsub print_uwhex (uword value @ AY, ubyte prefix @ Pc) clobbers(A,Y) {
; ---- print the uword in A/Y in hexadecimal form (4 digits)
; (if Carry is set, a radix prefix '$' is printed as well)
%asm {{
pha
tya
jsr print_ubhex
pla
clc
jmp print_ubhex
}}
}
asmsub print_uw0 (uword value @ AY) clobbers(A,Y) {
; ---- print the uword in A/Y in decimal form, with left padding 0s (5 positions total)
%asm {{
stx P8ZP_SCRATCH_REG_X
jsr c64utils.uword2decimal
ldy #0
- lda c64utils.uword2decimal.decTenThousands,y
beq +
jsr c64.CHROUT
iny
bne -
+ ldx P8ZP_SCRATCH_REG_X
rts
}}
}
asmsub print_uw (uword value @ AY) clobbers(A,Y) {
; ---- print the uword in A/Y in decimal form, without left padding 0s
%asm {{
stx P8ZP_SCRATCH_REG_X
jsr c64utils.uword2decimal
ldx P8ZP_SCRATCH_REG_X
ldy #0
- lda c64utils.uword2decimal.decTenThousands,y
beq _allzero
cmp #'0'
bne _gotdigit
iny
bne -
_gotdigit
jsr c64.CHROUT
iny
lda c64utils.uword2decimal.decTenThousands,y
bne _gotdigit
rts
_allzero
lda #'0'
jmp c64.CHROUT
}}
}
asmsub print_w (word value @ AY) clobbers(A,Y) {
; ---- print the (signed) word in A/Y in decimal form, without left padding 0's
%asm {{
cpy #0
bpl +
pha
lda #'-'
jsr c64.CHROUT
tya
eor #255
tay
pla
eor #255
clc
adc #1
bcc +
iny
+ jmp print_uw
}}
}
asmsub input_chars (uword buffer @ AY) clobbers(A) -> ubyte @ Y {
; ---- Input a string (max. 80 chars) from the keyboard. Returns length in Y. (string is terminated with a 0 byte as well)
; It assumes the keyboard is selected as I/O channel!
%asm {{
sta P8ZP_SCRATCH_W1
sty P8ZP_SCRATCH_W1+1
ldy #0 ; char counter = 0
- jsr c64.CHRIN
cmp #$0d ; return (ascii 13) pressed?
beq + ; yes, end.
sta (P8ZP_SCRATCH_W1),y ; else store char in buffer
iny
bne -
+ lda #0
sta (P8ZP_SCRATCH_W1),y ; finish string with 0 byte
rts
}}
}
asmsub setchr (ubyte col @Y, ubyte row @A) clobbers(A) {
; ---- set the character in SCRATCH_ZPB1 on the screen matrix at the given position
%asm {{
sty P8ZP_SCRATCH_REG
asl a
tay
lda _screenrows+1,y
sta _mod+2
lda _screenrows,y
clc
adc P8ZP_SCRATCH_REG
sta _mod+1
bcc +
inc _mod+2
+ lda P8ZP_SCRATCH_B1
_mod sta $ffff ; modified
rts
_screenrows .word $0400 + range(0, 1000, 40)
}}
}
asmsub getchr (ubyte col @Y, ubyte row @A) clobbers(Y) -> ubyte @ A {
; ---- get the character in the screen matrix at the given location
%asm {{
sty P8ZP_SCRATCH_B1
asl a
tay
lda setchr._screenrows+1,y
sta _mod+2
lda setchr._screenrows,y
clc
adc P8ZP_SCRATCH_B1
sta _mod+1
bcc _mod
inc _mod+2
_mod lda $ffff ; modified
rts
}}
}
asmsub setclr (ubyte col @Y, ubyte row @A) clobbers(A) {
; ---- set the color in SCRATCH_ZPB1 on the screen matrix at the given position
%asm {{
sty P8ZP_SCRATCH_REG
asl a
tay
lda _colorrows+1,y
sta _mod+2
lda _colorrows,y
clc
adc P8ZP_SCRATCH_REG
sta _mod+1
bcc +
inc _mod+2
+ lda P8ZP_SCRATCH_B1
_mod sta $ffff ; modified
rts
_colorrows .word $d800 + range(0, 1000, 40)
}}
}
asmsub getclr (ubyte col @Y, ubyte row @A) clobbers(Y) -> ubyte @ A {
; ---- get the color in the screen color matrix at the given location
%asm {{
sty P8ZP_SCRATCH_B1
asl a
tay
lda setclr._colorrows+1,y
sta _mod+2
lda setclr._colorrows,y
clc
adc P8ZP_SCRATCH_B1
sta _mod+1
bcc _mod
inc _mod+2
_mod lda $ffff ; modified
rts
}}
}
sub setcc (ubyte column, ubyte row, ubyte char, ubyte color) {
; ---- set char+color at the given position on the screen
%asm {{
lda row
asl a
tay
lda setchr._screenrows+1,y
sta _charmod+2
adc #$d4
sta _colormod+2
lda setchr._screenrows,y
clc
adc column
sta _charmod+1
sta _colormod+1
bcc +
inc _charmod+2
inc _colormod+2
+ lda char
_charmod sta $ffff ; modified
lda color
_colormod sta $ffff ; modified
rts
}}
}
asmsub plot (ubyte col @ Y, ubyte row @ A) clobbers(A) {
; ---- safe wrapper around PLOT kernel routine, to save the X register.
%asm {{
stx P8ZP_SCRATCH_REG_X
tax
clc
jsr c64.PLOT
ldx P8ZP_SCRATCH_REG_X
rts
}}
}
} ; ---- end block c64scr
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