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81 lines
2.9 KiB
Plaintext
81 lines
2.9 KiB
Plaintext
; C02 library stdio.h02 assembly language subroutines
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; Requires external routines GETKEY, PRCHR, DELCHR, NEWLIN, and SETSRC
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; external zero page locations SRCLO and SRCHI
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; and external constants DELKEY, ESCKEY, and RTNKEY
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;char getc() - GET Character from keyborad
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;Sets: System Dependent
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;Uses: System Dependent
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;Affects: System Dependent
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;Returns: A = Character Code of Key
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GETC EQU GETKEY ;Alias to external GETKEY routine
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;void putc(c) - PUT Character to screen
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;Args: Character code to display
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;Sets: System Dependent
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;Uses: System Dependent
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;Affects: System Dependent
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;Returns: System Dependent
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PUTC EQU PRCHR ;Alias to external PRCHR Routine
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;char gets(&s) - GET String input from keyboard
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;Args: Y,X = Address of String
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;Sets: SRCLO,SRCLHI = Address of String
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;Affects: N,Z,C
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;Returns: A,Y = Number of Characters in String
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GETS: JSR SETSRC ;Initialize Source String
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GETSL: JSR GETC ;Get Keypress
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CMP #DELKEY ;If Delete
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BNE GETSE ;Then
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TYA ; If Offset is Zero
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BEQ GETSL ; Get Next Character
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DEY ; Else Decrement Offset
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JSR DELCHR ; Delete Previous Character
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JMP GETSL ; and Get Next Character
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GETSE: CMP #ESCKEY ;Else If Escape
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BNE GETSC ;Then
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LDY #$FF ; Return -1
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BNE GETSY
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GETSC: CMP #RTNKEY ;Else If Not Carriage Return
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BEQ GETSX
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JSR PUTC ; Echo Character
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STA (SRCLO),Y ; Store Character at offset
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INY ; increment offset and
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BPL GETSL ; loop if less than 128
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GETSX: JSR NEWLIN ;Else Advance Cursor to Next Line
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LDA #$00 ; Terminate String
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STA (SRCLO),Y ; and
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GETSY: TYA ; Return String Length
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RTS
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;char puts(&s) - PUT String to screen
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;Args: Y,X = Address of String
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;Calls: PUTS
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;Affects: N,Z,C
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;Returns: A,Y = Number of Characters in String
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PUTS: LDA #$00 ;Set Start Position to 0
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;and fall into putsub
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;char putsub(n, &s) - PUT SUBstring to screen
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;Args: A = Starting Position in String
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; Y,X = Address of String
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;Sets: SRCLO,SRCLHI = Address of String
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;Calls: PUTC
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;Affects: N,Z,C
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;Returns: A,Y = Number of Characters in String
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PUTSUB: JSR SETSRC ;Initialize Source String
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TAY ;Initialize character offset
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PUTSUL: LDA (SRCLO),Y ;Read next character in string
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BEQ PUTSUX ;If Not 0
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JSR PUTC ; Print character at offset,
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INY ; increment offset, and
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BPL PUTSUL ; loop if less than 128
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PUTSUX: TYA ;Return number of
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RTS ; characters printed
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;char putln(&s) - PUT LiNe to screen
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;Args: Y,X = Address of String
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;Calls: PUTS and NEWLIN
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PUTLN: JSR PUTS ;Write string to screen
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JMP NEWLIN ;Execute external NEWLINe routine and return
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