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cc65/libsrc/pet/cputc.s
cuz 37178d5141 Make screensize() fetch the values dynamically instead of using variables
that are set on startup. This is needed to support the C128, which can switch
the screen size at runtime.


git-svn-id: svn://svn.cc65.org/cc65/trunk@2042 b7a2c559-68d2-44c3-8de9-860c34a00d81
2003-04-09 19:34:57 +00:00

119 lines
2.3 KiB
ArmAsm

;
; Ullrich von Bassewitz, 06.08.1998
;
; void cputcxy (unsigned char x, unsigned char y, char c);
; void cputc (char c);
;
.export _cputcxy, _cputc, cputdirect, putchar
.export newline, plot
.import popa, _gotoxy
.include "pet.inc"
_cputcxy:
pha ; Save C
jsr popa ; Get Y
jsr _gotoxy ; Set cursor, drop x
pla ; Restore C
; Plot a character - also used as internal function
_cputc: cmp #$0A ; CR?
bne L1
lda #0
sta CURS_X
beq plot ; Recalculate pointers
L1: cmp #$0D ; LF?
beq newline ; Recalculate pointers
; Printable char of some sort
cmp #' '
bcc cputdirect ; Other control char
tay
bmi L10
cmp #$60
bcc L2
and #$DF
bne cputdirect ; Branch always
L2: and #$3F
cputdirect:
jsr putchar ; Write the character to the screen
; Advance cursor position
advance:
cpy SCR_LINELEN ; xsize-1
bne L3
jsr newline ; new line
ldy #$FF ; + cr
L3: iny
sty CURS_X
rts
newline:
lda SCR_LINELEN ; xsize-1
sec ; Account for -1 above
adc SCREEN_PTR
sta SCREEN_PTR
bcc L4
inc SCREEN_PTR+1
L4: inc CURS_Y
rts
; Handle character if high bit set
L10: and #$7F
cmp #$7E ; PI?
bne L11
lda #$5E ; Load screen code for PI
bne cputdirect
L11: ora #$40
bne cputdirect
; Set cursor position, calculate RAM pointers
plot: ldy CURS_Y
lda ScrLo,y
sta SCREEN_PTR
lda ScrHi,y
ldy SCR_LINELEN
cpy #40+1
bcc @L1
asl SCREEN_PTR ; 80 column mode
rol a
@L1: ora #$80 ; Screen at $8000
sta SCREEN_PTR+1
rts
; Write one character to the screen without doing anything else, return X
; position in Y
putchar:
ora RVS ; Set revers bit
ldy CURS_X
sta (SCREEN_PTR),y ; Set char
rts
; Screen address tables - offset to real screen
.rodata
ScrLo: .byte $00, $28, $50, $78, $A0, $C8, $F0, $18
.byte $40, $68, $90, $B8, $E0, $08, $30, $58
.byte $80, $A8, $D0, $F8, $20, $48, $70, $98
.byte $C0
ScrHi: .byte $00, $00, $00, $00, $00, $00, $00, $01
.byte $01, $01, $01, $01, $01, $02, $02, $02
.byte $02, $02, $02, $02, $03, $03, $03, $03
.byte $03