mirror of
https://github.com/RevCurtisP/C02.git
synced 2024-11-24 15:31:17 +00:00
236 lines
9.7 KiB
Plaintext
236 lines
9.7 KiB
Plaintext
; C02 library memio.h02 assembly language subroutines
|
|
; Requires external routines SETDST, SETSRC
|
|
; zero page locations DSTLO, DSTHI, SRCLO and SRCHI
|
|
; location TEMP0
|
|
; and constant RTNKEY
|
|
|
|
;char maddr(mp) - Return Contents of Memory Pointer
|
|
;Args: A = Zero Page Memory Pointer
|
|
;Affects: N,Z reflect Y register
|
|
;Returns: A = Memory Pointer LSB
|
|
; Y = Memory Pointer MSB
|
|
; X = Zero Page Memory Pointet Address
|
|
MADDR: TAX ;Copy Pointer Address to X Register
|
|
LDA 0,X ;Load Pointer LSB into Accumulator
|
|
LDY 1,X ;Load Pointer MSB into Y Register
|
|
RTS
|
|
|
|
;char mopen(mp, &a) - Open Memory File: Set Memory Pointer to specified Address
|
|
;Args: A = Zero Page Memory Pointer
|
|
; X,Y = Address
|
|
;Sets: TEMP0 = Memory Pointer Address
|
|
;Affects: N,Z reflect Accumulator
|
|
;Returns: A = Zero Page Memory Pointer, otherwise
|
|
; 0 if Error Illegal Address (within Zero Page)
|
|
MOPEN: STX TEMP0 ;Save Address LSB
|
|
TAX ;Copy Memory Pointer to X register
|
|
LDA TEMP0 ;Retrieve Address LSB
|
|
STA 0,X ;Store in Memory Pointer LSB
|
|
STY 1,X ;Store Address MSB in Memory Pointer MSB
|
|
LDA 1,X ;Load Address MSB into Accumulator (Setting Flags)
|
|
BEQ MERROX ;If 0, Return as Result (Failure)
|
|
TXA ;Else
|
|
RTS ; Return Memory Pointer as Result
|
|
|
|
;char meof(mp) - Check for End of Memory File
|
|
;Args: A = Zero Page Memory Pointer
|
|
;Affects: N,Z reflect Accumulator
|
|
;Returns: A,Y = 255 if at End of File or invalid Memory Pointer
|
|
; 0 otherwise
|
|
; X = Zero Page Memory Pointer
|
|
MEOF: JSR MERROR ;Check Memory Pointer
|
|
BNE MCLOSX ;If Error, Return Else Y will contain 0
|
|
LDA (0,X) ;If NUL Character at Memory Pointer
|
|
BEQ MERROY ; Return 255
|
|
BNE MERROX ;Else Return 0
|
|
|
|
|
|
;char merror(mp) - Check for Memory File Error
|
|
;Args: A = Zero Page Memory Pointer
|
|
;Affects: N,Z reflect Accumulator
|
|
;Returns: A,Y = 255 if Memory Pointer contains Zero Page Address
|
|
; 0 if no error
|
|
; X = Zero Page Memory Pointer
|
|
MERRON: STY TEMP1 ;Alternate Entry Point - Save Byte Argument
|
|
MERROM: STA TEMP0 ;Alternate Entry Point - Save Memory Pointer
|
|
MERROR: TAX ;Copy Memory Pointer to X register
|
|
MERROA: LDY #0 ;Set Error Indicator to 0
|
|
LDA 1,X ;Load Memory Address High Byte
|
|
BEQ MERROY ;If 0
|
|
CMP #255 ; or
|
|
BNE MERROX ; 255
|
|
MERROY: DEY ; Change Error Indicator to 255
|
|
MERROX: TYA ;Copy Error Indicator to Accumulator
|
|
RTS
|
|
|
|
;char mclose(mp) - Close Memory File: Write EOF and Clear Memory Pointer
|
|
;Args: A = Zero Page Memory Pointer
|
|
;Affects: N,Z reflect Accumulator
|
|
;Returns: A,Y = 255 if Memory Pointer contains Zero Page Address
|
|
; 0 if no error
|
|
; X = Zero Page Memory Pointer
|
|
MCLOSE: JSR MFLUSH ;Check Memory Pointer
|
|
BNE MCLOSX ;If No Error
|
|
STA 0,X ; Write to Addess LSB
|
|
STA 1,X ; Write to Addess LSB
|
|
MCLOSX: RTS
|
|
|
|
;char mflush(mp) - Flush Memory File: Write NUL at Memory Pointer
|
|
;Args: A = Zero Page Memory Pointer
|
|
;Affects: N,Z reflect Accumulator
|
|
;Returns: A,Y = 255 if Memory Pointer contains Zero Page Address
|
|
; 0 if no error
|
|
; X = Zero Page Memory Pointer
|
|
MFLUSH: JSR MERROR ;Check Memory Pointer
|
|
BNE MCLOSX ;If No Error
|
|
STA (0,X) ; to Current Memory Location
|
|
MFLUSX: RTS
|
|
|
|
;char mgetc(mp) - Read Character from Memory File
|
|
;Args: A = Zero Page Memory Pointer
|
|
;Affects: N,Z reflect Accumulator
|
|
;Returns: A = Character read from memory
|
|
; Y = 255 if Error or EOF
|
|
; 0 if no error
|
|
; X = Zero Page Memory Pointer
|
|
MGETC: JSR MERROR ;Check Memory Pointer
|
|
BNE MGETCX ;If No Error
|
|
LDA (0,X) ; Load Character at Memory Location
|
|
MGETCI: PHP ; Save Flags
|
|
INC 0,X ; Increment Memory Pointer Low Byte
|
|
BNE MGETCP ; If 0
|
|
INC 1,X ; Increment Memory Pointer High Byte
|
|
MGETCP: PLP ; Restore Flags
|
|
MGETCX: RTS
|
|
|
|
;char mputc(mp, c) - Write Character to Memory File
|
|
;Args: A = Zero Page Memory Pointer
|
|
; Y = Character to Write to Memory
|
|
;Sets: TEMP0 = Character to Write
|
|
;Affects: N,Z reflect Accumulator
|
|
;Returns: A,Y = 255 if invalid Memory Pointer
|
|
; 0 if no error
|
|
; X = Zero Page Memory Pointer
|
|
MPUTC: JSR MERRON ;Save Argumebts & Check Memory Pointer
|
|
BNE MGETCX ;If Error, then Return
|
|
LDA TEMP1 ;Retrieve Character to Write
|
|
STA (0,X) ;Store in Memory
|
|
LDA #0 ;Clear Accumulator, Z and N flags
|
|
BEQ MGETCI ;and Increment Memory Pointer
|
|
|
|
;char mgets(mp, &s) - Read from Memory File into String
|
|
;Args: A = Zero Page Memory Pointer
|
|
; Y,X = Address of String to Read into
|
|
;Sets: TEMP0 = Memory Pointer
|
|
; TEMP1 = Number of characters read
|
|
;Affects: N,Z reflect Accumulator
|
|
;Returns: A = 255 if invalid Memory Pointer
|
|
; otherwise length of string read
|
|
; Y = Last character in string
|
|
; X = Zero Page Memory Pointer
|
|
MGETS: JSR SETDST ;Set String Address as Destination
|
|
JSR MERROM ;Save Memory Pointer & Check Memory Pointer
|
|
BNE MGETCX ;If Error then Return, Else Y will be 0
|
|
LDA 0,X ;Copy Memory Pointer LSB
|
|
STA SRCLO ;to Source Pointer LSB
|
|
LDA 1,X ;Copy Memory Pointer MSB
|
|
STA SRCHI ;to Source Pointer MSB
|
|
MGETSL: LDA (SRCLO),Y ;Get Character from Memory
|
|
BEQ MGETSX ;If Not NUL (End of File)
|
|
CMP #32 ; Check for Control Character
|
|
MGETSS: STA (DSTLO),Y ; Store Character in String
|
|
INY ; increment offset and
|
|
BCC MGETSX ; If Not Control character
|
|
BPL MGETSL ; loop if less than 128
|
|
MGETSX: TAX ;Copy Final Character to X
|
|
LDA #$00 ;Terminate String
|
|
STA (DSTLO),Y ;
|
|
BEQ MPUTSX ;Update Memory Pointer and Return String Length
|
|
|
|
;char mputs(mp, &s) - Write String to Memory File
|
|
;Args: A = Zero Page Memory Pointer
|
|
; Y,X = Address of String to Read into
|
|
;Sets: TEMP0 = Memory Pointer
|
|
; TEMP1 = Number of characters written
|
|
;Affects: N,Z reflect Accumulator
|
|
;Returns: A = 255 if invalid Memory Pointer
|
|
; otherwise length of string written
|
|
; Y = Last character in string
|
|
; X = Zero Page Memory Pointer
|
|
MPUTS: JSR SETSRC ;Set Source Pointer
|
|
JSR MERROM ;Save Memory Pointer & Check Memory Pointer
|
|
BNE MGETCX ;If Error then Return, Else Y will be 0
|
|
LDA 0,X ;Copy Memory Pointer LSB
|
|
STA DSTLO ;to Source Pointer LSB
|
|
LDA 1,X ;Copy Memory Pointer MSB
|
|
STA DSTHI ;to Source Pointer MSB
|
|
MPUTSL: LDA (SRCLO),Y ;Get Character from Memory
|
|
BEQ MPUTSX ;If Not End of String
|
|
STA (DSTLO),Y ; Store Character in Memory
|
|
TAX ; and copy into X Register
|
|
INY ; Increment offset and
|
|
BPL MPUTSL ; loop if less than 128
|
|
MPUTSX: TXA ;Copy Final Character into Accumulator
|
|
LDX TEMP0 ;Retrieve Memory Pointer
|
|
STY TEMP1 ;Save String Length in TEMP1
|
|
TAY ;Copy Final Character into Y-Register
|
|
MPUTSY: LDA 0,X ;Get Memory Pointer LSB
|
|
CLC
|
|
ADC TEMP1 ;Add String Length
|
|
STA 0,X
|
|
BCC MGETSZ ;If Carry
|
|
INC 1,X ; Increment Memory Pointer MSB
|
|
MGETSZ: LDA TEMP1 ;Load String Length and Set Flags
|
|
RTS
|
|
|
|
;char mputln(&s) - Write Line to Memory File
|
|
MPUTLN: JSR MPUTS ;Write String to Memory File
|
|
LDA TEMP0 ;Retrieve Memory Pointer
|
|
LDY #RTNKEY ;Load Carriage Return
|
|
JMP MPUTC ;Write to Memory File
|
|
|
|
;mdst(&a) - Set Destination Array for mread()
|
|
MDST EQU SETDST
|
|
|
|
;char mread(mp, n) - Read from Memory File into Array
|
|
;Args: A = Zero Page Memory Pointer
|
|
; Y = Number of Bytes to Read
|
|
;Sets: TEMP0 = Memory Pointer
|
|
; TEMP1 = Number of characters read
|
|
;Affects: N,Z reflect Accumulator
|
|
;Returns: A,Y = 255 if invalid Memory Pointer
|
|
; otherwise number of bytes read
|
|
; X = Zero Page Memory Pointer
|
|
MREAD: JSR MERRON ;Save Argumebts & Check Memory Pointer
|
|
BNE MGETCX ;If Error then Return, Else Y will be 0
|
|
LDA 0,X ;Copy Memory Pointer LSB
|
|
STA SRCLO ;to Source Pointer LSB
|
|
LDA 1,X ;Copy Memory Pointer MSB
|
|
STA SRCHI ;to Source Pointer MSB
|
|
BNE MWRITL ;Execute Copy
|
|
|
|
;msrc(&a) - Set Source Array for mwrite()
|
|
MSRC EQU SETSRC
|
|
|
|
;char mwrite(mp, n) - Read from Memory File into Array
|
|
;Args: A = Zero Page Memory Pointer
|
|
; Y = Number of Bytes to Read
|
|
;Sets: TEMP0 = Memory Pointer
|
|
; TEMP1 = Number of characters read
|
|
;Affects: N,Z reflect Accumulator
|
|
;Returns: A,Y = 255 if invalid Memory Pointer
|
|
; otherwise number of bytes written
|
|
; X = Zero Page Memory Pointer
|
|
MWRITE: JSR MERRON ;Save Argumebts & Check Memory Pointer
|
|
BNE MGETCX ;If Error then Return, Else Y will be 0
|
|
LDA 0,X ;Copy Memory Pointer LSB
|
|
STA DSTLO ;to Destination Pointer LSB
|
|
LDA 1,X ;Copy Memory Pointer MSB
|
|
STA DSTHI ;to Destination Pointer MSB
|
|
MWRITL: LDA (SRCLO),Y ;Read Byte from Memory
|
|
STA (DSTLO),Y ;Write Byte to Array
|
|
INY ;Increment Index
|
|
CPY TEMP1 ;If Not Equal to Number of Bytes to Read
|
|
BNE MWRITL ; Loop
|
|
BEQ MPUTSY ;Else Update Memory Pointer
|