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50 lines
630 B
Plaintext
50 lines
630 B
Plaintext
; Basic test of char I/O emulation
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.ORG $0200
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CHRGET = $E000
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PUTCH = $E000
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TXTBUF = $0400
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CR = $0D
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NL = $0A
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START: LDX #$00
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PR1: LDA PROMPT,X ;print prompt
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BEQ L0
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STA PUTCH
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INX
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BNE PR1
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L0: LDX #$00
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GETTXT: LDA CHRGET ;get text from input
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BEQ GETTXT
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CMP #CR
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BEQ L1
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CMP #NL
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BEQ L1
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STA PUTCH ;echo char
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STA TXTBUF,X ;store char
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INX
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BNE GETTXT
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L1: LDA #NL ; add line break
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STA TXTBUF,X
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STA PUTCH
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INX
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LDA #CR
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STA TXTBUF,X
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STA PUTCH
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INX
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LDA #$00 ; add null
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STA TXTBUF,X
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TAX
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PRINT: LDA TXTBUF,X ; print to output
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BEQ L2
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STA PUTCH
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INX
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BNE PRINT
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L2: BRK
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NOP
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JMP START
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PROMPT: .DB "Enter text:",0
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