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222668c016
If kbhit() detects that a key is pressed, it fetches and buffers the character. If cgetc() detects a buffered character, this one is returned instead of fetching one with the PROM routine.
49 lines
1.6 KiB
ArmAsm
49 lines
1.6 KiB
ArmAsm
;
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; char cgetc (void);
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;
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.constructor initcgetc
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.export _cgetc
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.import cursor
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.include "osic1p.inc"
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.include "extzp.inc"
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.include "zeropage.inc"
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; Initialize one-character buffer that is filled by kbhit()
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initcgetc:
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lda #$00
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sta CHARBUF ; No character in buffer initially
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rts
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; Input routine from 65V PROM MONITOR, show cursor if enabled
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_cgetc:
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lda CHARBUF ; character in buffer available?
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beq nobuffer
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tax ; save character in X
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lda #$00
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sta CHARBUF ; empty buffer
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jmp restorex ; restore X and return
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nobuffer:
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lda cursor ; show cursor?
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beq nocursor
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ldy CURS_X
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lda (SCREEN_PTR),y ; fetch current character
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sta tmp1 ; save it
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lda #$A1 ; full white square
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sta (SCREEN_PTR),y ; store at cursor position
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nocursor:
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jsr INPUTC ; get input character in A
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ldx cursor
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beq done ; was cursor on?
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tax ; save A in X
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lda tmp1 ; fetch saved character
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ldy CURS_X
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sta (SCREEN_PTR),y ; store at cursor position
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restorex:
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txa ; restore saved character from X
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done:
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ldx #$00 ; high byte of int return value
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rts
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