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99 lines
2.3 KiB
ArmAsm
99 lines
2.3 KiB
ArmAsm
;
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; 2019-09-23, Greg King
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;
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; void __fastcall__ cputcxy (unsigned char x, unsigned char y, char c);
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; void __fastcall__ cputc (char c);
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;
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.export _cputcxy, _cputc, cputdirect, putchar
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.export newline, plot
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.import gotoxy, PLOT
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.include "cx16.inc"
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.macpack generic
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; First, move to a new position.
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_cputcxy:
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pha ; Save C
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jsr gotoxy ; Set cursor, drop x and y
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pla ; Restore C
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; Print a character.
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_cputc: cmp #$0D ; LF?
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beq newline
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cmp #$0A ; CR?
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beq plotx0
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; Printable char of some sort
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cmp #' '
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blt cputdirect ; Other control char
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tay
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bmi L10
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cmp #$60
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blt L2
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and #<~%00100000
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bra cputdirect
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; Handle character if high bit set
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L10: and #<~%10000000 ; Remove high bit
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ora #%01000000
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bra cputdirect
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L2: and #<~%01000000
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cputdirect:
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jsr putchar ; Write character to screen, return .Y
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; Advance cursor position.
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iny
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cpy LLEN ; Reached end of line?
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bne L3
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jsr newline ; Next line
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ldy #$00 ; + CR
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L3: sty CURS_X
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rts
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; Move down.
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newline:
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inc SCREEN_PTR+1
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inc CURS_Y
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rts
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; Set the cursor's position, calculate RAM pointer.
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plotx0: stz CURS_X
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plot: ldy CURS_X
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ldx CURS_Y
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clc
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jmp PLOT ; Set the new cursor
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; Write one screen-code and color to the video RAM without doing anything else.
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; Return the x position in .Y .
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putchar:
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ora RVS ; Set revers bit
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tax
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stz VERA::CTRL ; Use port 0
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lda CURS_Y
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sta VERA::ADDR+1 ; Set row number
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lda #VERA::INC1 ; Address increments by one
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sta VERA::ADDR+2
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ldy CURS_X ; Get character column into .Y
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tya
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asl a ; Each character has two bytes
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sta VERA::ADDR
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stx VERA::DATA0
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lda CHARCOLOR
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sta VERA::DATA0
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rts
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