mirror of https://github.com/RevCurtisP/C02.git
105 lines
3.5 KiB
Plaintext
105 lines
3.5 KiB
Plaintext
PROCESSOR 6502
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ORG $0200
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; ctype.h02 assembly language subroutines
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;
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; All calls replace Accumulator and set Flags
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; Index Registers are not Modified
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; isxxxx will load $FF into Accumulator to and Set Carry if True
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; and load $00 into Accumulator to and clear Carry if False
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; toxxxx set Carry if character is converted, otherwise clear Carry
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;Character Test Routines
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isalnm: JSR isdigt ;If Char is Digit
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BCS isrts ; Return TRUE
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;Else
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isalph: JSR isuppr ;If Char is Upper Case
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BCS isrts ; Return TRUE
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;Else
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islowr: JSR islwc ;If Char is Lower Case
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BVC isbft ; Return FALSE Else Return TRUE
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; BCS isfls ; Return FALSE
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; BCC istru ;Else Return TRUE
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isuppr: JSR isupc ;If Char is Uppercase
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BVC isbft ; Return FALSE Else Return TRUE
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; BCS isfls ; Return FALSE
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; BCC istru ;Else Return TRUE
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isctrl: CLV ;Clear Overflow
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CMP #$7F ;If Char = DEL
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BEQ istru ; Return TRUE
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CMP #$20 ;Else If Char < ' '
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BVC isbft ; Return TRUE Else Return FALSE
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; BCC istru ; Return TRUE
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; BCS isfls ;Else Return FALSE
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isdigt: CLV ;Clear Overflow
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CMP #$30 ;If Char < '0'
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BCC isfls ; Return FALSE
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CMP #$3A ;Else If Char >= ':'
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BVC isbft ; Return FALSE Else Return TRUE
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; BCS isfls ; Return FALSE
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; BCC istru ;Else Return True
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ispnct: JSR isalnm ;If Char is Alphanumeric
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BNE isfls ; Return FALSE
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;Else
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isgrph: CMP #$20 ;If Char is Space
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BEQ isfls ; Return FALSE
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;Else
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isprnt: JSR isctrl ;If Char is Not Control
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BVC isbft ; Return TRUE Else Return FALSE
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; BCC istru ; Return TRUE
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; BCS isfls ;Else Return FALSE
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isspc: CLV ;Clear Overflow
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CMP #$20 ;If Char is ' '
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BEQ istru ; Return TRUE
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CMP #$09 ;If Char < '\t'
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BCC isfls ; Return TRUE
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CMP #$0E ;Else If Char > '\r'
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BVC isbft ; Return FALSE Else Return TRUE
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; BCS isfls ; Return FALSE
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; BCC istru ;Else Return TRUE
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isxdgt: JSR touppr ;Convert to Uppercase
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CMP #$41 ;If Char < 'A'
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BCC isdigt ; Check for Digit
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CMP #$5B ;Else If Char >= 'G'
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isbft: BCS isfls ; Return FALSE
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;Else
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istru: LDA #$FF ;Return TRUE
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issec: SEC ;Set Carry
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RTS ;and Return
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isfls: LDA #$00 ;Return FALSE
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isclc: CLC ;Clear Carry
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isrts: RTS ;Return from Subroutine
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;Internal Test Routines - Do Not Change Accumulator
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islwc: CLV ;Clear Overflow for Calling Routine
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CMP #$61 ;If Char < 'a'
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BCC isrts ; Return with Carry Clear
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CMP #$7B ;Else If Char >= '{'
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BCS isclc ; Return with Carry Clear
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BCC issec ;Else Return with Carry Set
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isupc: CLV ;Clear Overflow for Calling Routine
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CMP #$41 ;If Char < 'A'
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BCC isrts ; Return with Carry Clear
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CMP #$5B ;Else If Char >= '['
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BCS isclc ; Return with Carry Clear
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BCC issec ;Else Return with Carry Set
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;Character Conversion Routines
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tolowr: JSR isupc ;If Char is Not Upper Case
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BCC isrts ; Return
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ORA $20 ;Else Set Bit 6
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RTS ; and Return
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touppr: JSR islwc ;If Char is Not Lower Case
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BCC isrts ; Return
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AND $DF ;Else Clear Bit 6
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RTS ; and Return
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