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prodos-more/more.s
Bill Chatfield 7377bf0f90 Don't remember
2019-05-02 21:26:12 -04:00

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*
* more - Text viewer
*
* BEQ - Branch if Equal
* Branches if the zero flag (Z) is set to 1. This happens if:
* - A 0 value is loaded into the accumulator via LDA
* - A CMP is done on two equal values
* - A SBC is done on two equal values?
* BCC - Branch if Carry Flag is Clear
* Equivalent to Branch if Less Than (BLT), meaning that the
* accumulator (A) is less than the parameter: A < Param
* BGE - Branch if Accum >= Param is BCS
PROMPT equ $33
BUFF equ $200
* System subroutines stored in Monitor ROM
GETLN equ $fd6a ; Reads a line of input, with prompt from $33
GETLNZ equ $fd67 ; Reads a line of input, CR first
GETLN1 equ $fd6f ; Reads a line of input, no prompt
CROUT equ $fd8e ; Outputs a carriage return
PRBYTE equ $fdda ; Outputs a byte
COUT equ $fded ; Outputs a character
* MLI stands for Machine Language Interface
* It is the ProDOS system call entry point
MLI equ $bf00
* ProDOS system call command codes
OPEN equ $c8
READ equ $ca
CLOSE equ $cc
* Constants
EOF equ $4c ; End of file
PTR equ $06
MAX_EC equ $5a ; The largest error code
CR equ $0d ; Carriage return
BUF_SIZ equ $00ff
WRITE_CHAR mac
if #=]1
lda ]1
else
lda #]1
fin
jsr COUT
eom
WRITE_BYTE mac
lda ]1
jsr PRBYTE
eom
WRITE_ASC mac
tya ; Preserve Y by transferring it to A
pha ; and pushing it onto the stack
ldy #0 ; Prepare loop index
nextch lda ]1,Y ; Load a character into A
beq finish ; Branch if lda loaded a zero value
jsr COUT ; Write the character in A
iny ; Increment Y
jmp nextch ; Go back and load the next character
finish pla ; Restore Y by pulling stack into A
tay ; and transferring it to Y
eom
WRITE_STR mac
tya ; Preserve Y
pha
lda ]1 ; Length byte
sta len
ldy #1 ; Prepare loop index
nextChar tya
cmp len ; Check if beyond end of string
bcc writeChar ; Y is Less than
beq writeChar ; or equal to len
jmp finish
writeChar lda ]1,y ; Load a character
jsr COUT
iny
jmp nextChar
len db 0
finish pla ; Restore Y
tay
eom
COPY_BYTE mac
lda ]1
sta ]2
eom
* Copies a line out of BUFF into ]1.
* Length is in X as is done by GETLN.
COPY_BUFF mac
tya ; Preserve Y register
pha ; by pushing it on the stack
txa ; Transfer X to A for compare
cmp #$ff ; Check if string is too long
bne startCopy ; If not, get started
dex ; If so, shrink to fit with length byte
startCopy stx ]1 ; Store length to target string
ldy #0 ; Initialize loop index
nextChar tya ; Move current position to A
cmp ]1 ; Compare current position with length
beq endCopyLine ; Quit if we've reached the end
lda BUFF,y ; Load current character
iny ; BUFF and ]1 are off by 1 because of len byte
sta ]1,y ; Store character into target string
jmp nextChar ; Continue with next character
endCopyLine pla ; Restore Y by pulling value from stack
tay ; and transferring to Y
eom
WRITE_BUFF mac
tya
pha
stx len
ldy #0
nextByte tya
cmp len
beq done
lda BUFF,y
jsr COUT
iny
jmp nextByte
done pla
tay
eom
* Starting at $9000 because:
* $800 overwrites Applesoft
* $803 is where Applesoft programs start
* $2000 is where the current .SYSTEM program is loaded
mainProgram
org $8000
getFileNam
WRITE_ASC prompt
COPY_BYTE #"?";PROMPT
jsr GETLN1
WRITE_ASC buffText
WRITE_BUFF
jsr CROUT
COPY_BUFF fileName
openFile jsr MLI
db OPEN
da openParams
bne openErrorHandler
readFile COPY_BYTE fileNum;readNum
readNext jsr MLI
db READ
da readParams
cmp #EOF
beq closeFile
cmp #0
bne readErrorHandler
writeScreen
ldy #0
sty lineCount
sty charCount
nextChar lda readIoBuf,y
inc charCount
ora #$80
jsr COUT
cmp $0d
bne continue
inc lineCount
continue cpy #<BUF_SIZ
beq readNext
iny
jmp nextChar
closeFile COPY_BYTE fileNum;closeNum
jsr MLI
db CLOSE
dw closeParams
bne closeErrorHandler
jmp endMain
openErrorHandler
sta errorCode
WRITE_ASC openFailureText
jmp errorHandler
readErrorHandler
sta errorCode
WRITE_ASC readFailureText
jmp errorHandler
closeErrorHandler
sta errorCode
WRITE_ASC closeFailureText
errorHandler
WRITE_STR fileName
WRITE_CHAR ":"
WRITE_CHAR " "
lda errorCode
cmp #MAX_EC ; Compare by A - MAX_EC
bcs unknownError ; Branch if A >= MAX_EC
lda errorCode ; Necessary?
clc ; Prepare for addition
adc errorCode ; Double for indexing addresses
tax
lda errorMessages,x
sta PTR
inx
lda errorMessages,x
sta PTR+1
bne writeError
lda PTR
bne writeError
unknownError
WRITE_ASC unknownErrorCodeText
WRITE_CHAR "$"
WRITE_BYTE errorCode
jsr CROUT
jmp endMain
writeError
WRITE_ASC (PTR)
WRITE_CHAR " "
WRITE_ASC errorCodeText
WRITE_CHAR "$"
WRITE_BYTE errorCode
WRITE_CHAR ")"
jsr CROUT
endMain
COPY_BYTE #"]";PROMPT ; Restore normal prompt
rts
* DAT-uh
openParams db 3 ; Parameter count
oPathPtr da fileName ; Input param - file to open
oBufPtr da openIoBuf ; Input param - I/O buffer
fileNum ds 1 ; Output param - file ref num
readParams db 4
readNum ds 1
da readIoBuf
reqCount dw BUF_SIZ
transCount ds 2
closeParams db 1 ; Parameter count
closeNum db 0 ; Input param - ref num to close
fileName ds $ff ; String starting with length byte
charCount ds 2
lineCount ds 1
len ds 1
buffText asc "BUFF=",00
prompt asc "ENTER FILE NAME: ",00
errorCode db 0
openFailureText asc "FAILED TO OPEN FILE ",00
readFailureText asc "FAILED TO READ FILE ",00
closeFailureText asc "FAILED TO CLOSE FILE ",00
errorCodeText asc "(ERROR CODE ",00
unknownErrorCodeText asc "UNKNOWN ERROR CODE: ",00
em00 asc "NO ERROR",00
em01 asc "BAD SYSTEM CALL NUMBER",00
em03 asc "NO DEVICE CONNECTED",00 ; Bug in AppleWin < 1.26.3.0
em04 asc "BAD SYSTEM CALL PARAMETER COUNT",00
em25 asc "INTERRUPT VECTOR TABLE FULL",00
em27 asc "I/O ERROR",00
em28 asc "DEVICE NOT CONNECTED",00
em2b asc "DISK WRITE PROTECTED",00
em2e asc "DISK SWITCHED WHILE FILE STILL OPEN",00
em40 asc "PATH CONTAINS ILLEGAL CHARACTERS",00
em42 asc "CANNOT EXCEED 8 OPEN FILES",00
em44 asc "PATH NOT FOUND",00
em45 asc "VOLUME DIRECTORY NOT FOUND",00
em46 asc "FILE NOT FOUND",00
em47 asc "DUPLICATE FILENAME",00
em48 asc "DISK IS FULL",00
em49 asc "CANNOT EXCEED 51 DIRECTORY ENTRIES",00
em4a asc "INCOMPATIBLE FILE FORMAT",00
em4b asc "UNSUPPORTED STORAGE TYPE",00
em4c asc "END OF FILE",00
em4d asc "FILE POSITION OUT OF RANGE",00
em4e asc "FILE ATTRIBUTE FORBIDS OPERATION",00
em50 asc "FILE IS OPEN",00
em51 asc "DIRECTORY COUNT ERROR",00
em52 asc "NOT A PRODOS DISK",00
em55 asc "VOLUME CONTROL BLOCK FULL",00
em56 asc "BAD BUFFER ADDRESS",00
em57 asc "DUPLICATE VOLUME",00
em5a asc "BIT MAP DISK ADDRESS IS IMPOSSIBLE",00
*
* ERROR CODE TO MESSAGE TRANSLATION TABLE
*
errorMessages
ec00 da em00
ec01 da em01
ec02 da $0000
ec03 da em03 ; Bug in AppleWin < 1.26.3.0
ec04 da em04
ec05 da $0000
ec06 da $0000
ec07 da $0000
ec08 da $0000
ec09 da $0000
ec0a da $0000
ec0b da $0000
ec0c da $0000
ec0d da $0000
ec0e da $0000
ec0f da $0000
ec10 da $0000
ec11 da $0000
ec12 da $0000
ec13 da $0000
ec14 da $0000
ec15 da $0000
ec16 da $0000
ec17 da $0000
ec18 da $0000
ec19 da $0000
ec1a da $0000
ec1b da $0000
ec1c da $0000
ec1d da $0000
ec1e da $0000
ec1f da $0000
ec20 da $0000
ec21 da $0000
ec22 da $0000
ec23 da $0000
ec24 da $0000
ec25 da $0000
ec26 da $0000
ec27 DA em27
ec28 DA em28
ec29 da $0000
ec2a da $0000
ec2b da $0000
ec2c da $0000
ec2d da $0000
ec2e DA em2e
ec2f da $0000
ec30 da $0000
ec31 da $0000
ec32 da $0000
ec33 da $0000
ec34 da $0000
ec35 da $0000
ec36 da $0000
ec37 da $0000
ec38 da $0000
ec39 da $0000
ec3a da $0000
ec3b da $0000
ec3c da $0000
ec3d da $0000
ec3e da $0000
ec3f da $0000
ec40 da em40
ec41 da $0000
ec42 da em42
ec43 da $0000
ec44 da em44
ec45 da em45
ec46 da em46
ec47 da em47
ec48 da em48
ec49 da em49
ec4a da em4a
ec4b da em4b
ec4c da em4c
ec4d da em4d
ec4e da em4e
ec4f da $0000
ec50 da em50
ec51 da em51
ec52 da em52
ec53 da $0000
ec54 da $0000
ec55 da em55
ec56 da em56
ec57 da em57
ec58 da $0000
ec59 da $0000
ec5a da em5a
*
* Consume all bytes up to next page boundary
*
filler ds \,$00
*
* Must start on page boundary
*
openIoBuf ds 1024
readIoBuf ds BUF_SIZ
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