mirror of
https://github.com/SEPPDROID/Digital-Research-Source-Code.git
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288 lines
6.7 KiB
Plaintext
288 lines
6.7 KiB
Plaintext
;
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;****************************************************
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;* *
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;* Sample Random Access Program for CP/M-86 *
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;* *
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;****************************************************
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;
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; BDOS Functions
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;
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coninp equ 1 ;console input function
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conout equ 2 ;console output function
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pstring equ 9 ;print string until '$'
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rstring equ 10 ;read console buffer
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version equ 12 ;return version number
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openf equ 15 ;file open function
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closef equ 16 ;close function
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makef equ 22 ;make file function
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readr equ 33 ;read random
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writer equ 34 ;write random
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;
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; Equates for non graphic characters
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cr equ 0dh ;carriage return
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lf equ 0ah ;line feed
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;
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;
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; load SP, ready file for random access
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;
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cseg
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pushf ;push flags in CCP stack
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pop ax ;save flags in AX
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cli ;disable interrupts
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mov bx,ds ;set SS register to base of DATA group
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mov ss,bx ;set SS, SP with interrupts disabled
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mov sp,offset stack ; for 80888
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push ax ;restore the flags
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popf
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;
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; CP/M-86 initial release returns the file
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; system version number of 2.2: check is
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; shown below for illustration purposes.
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;
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mov cl,version
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call bdos
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cmp al,20h ;version 2.0 or later?
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jnb versok
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; bad version, message and go back
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mov dx,offset badver
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call print
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jmp abort
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;
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versok:
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; correct version for random access
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mov cl,openf ;open default fct
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mov dx,offset fcb
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call bdos
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inc al ;err 255 becomes zero
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jnz ready
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;
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; cannot open file, so create it
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mov cl,makef
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mov dx,offset fcb
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call bdos
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inc al ;err 255 becomes zero
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jnz ready
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;
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; cannot create file, directory full
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mov dx,offset nospace
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call print
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jmp abort ;back to ccp
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;
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; loop back to "ready" after each command
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;
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ready:
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; file is ready for processing
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;
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call readcom ;read next command
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mov ranrec,dx ;store input record#
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mov ranovf,0h ;clear high byte if set
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cmp al,'Q' ;quit?
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jnz notq
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;
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; quit processing, close file
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mov cl,closef
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mov dx,offset fcb
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call bdos
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inc al ;err 255 becomes 0
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jz error ;error message, retry
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jmps abort ;back to ccp
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;
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;
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; end of quit command, process write
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;
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;
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notq:
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; not the quit command, random write?
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cmp al,'W'
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jnz notw
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;
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; this is a random write, fill buffer until cr
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mov dx,offset datmsg
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call print ;data prompt
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mov cx,127 ;up to 127 characters
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mov bx,offset buff ;destination
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rloop: ;read next character to buff
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push cx ;save loop conntrol
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push bx ;next destination
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call getchr ;character to AL
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pop bx ;restore destination
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pop cx ;restore counter
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cmp al,cr ;end of line?
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jz erloop
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; not end, store character
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mov byte ptr [bx],al
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inc bx ;next to fill
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loop rloop ;decrement cx ..loop if not 0
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erloop:
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; end of read loop, store 00
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mov byte ptr [bx],0h
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;
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; write the record to selected record number
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mov cl,writer
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mov dx,offset fcb
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call bdos
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or al,al ;error code zero?
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jz ready ;for another record
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jmps error ;message if not
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;
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;
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;
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; end of write command, process read
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;
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;
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notw:
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; not a write command, read record?
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cmp al,'R'
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jz ranread
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jmps error ;skip if not
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;
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; read random record
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ranread:
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mov cl,readr
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mov dx,offset fcb
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call bdos
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or al,al ;return code 00?
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jz readok
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jmps error
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;
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; read was successful, write to console
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readok:
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call crlf ;new line
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mov cx,128 ;max 128 characters
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mov si,offset buff ;next to get
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wloop:
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lods al ;next character
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and al,07fh ;mask parity
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jnz wloop1
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jmp ready ;for another command if 00
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wloop1:
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push cx ;save counter
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push si ;save next to get
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cmp al,' ' ;graphic?
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jb skipw ;skip output if not graphic
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call putchr ;output character
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skipw:
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pop si
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pop cx
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loop wloop ;decrement CX and check for 00
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jmp ready
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;
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;
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; end of read command, all errors end-up here
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;
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;
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error:
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mov dx,offset errmsg
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call print
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jmp ready
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;
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; BDOS entry subroutine
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bdos:
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int 224 ;entry to BDOS if by INT 224
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ret
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;
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abort: ;return to CCP
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Mov Dl, 0
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mov cl,0
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call bdos ;use function 0 to end execution
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;
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; utility subroutines for console i/o
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;
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getchr:
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;read next console character to a
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mov cl,coninp
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call bdos
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ret
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;
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putchr:
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;write character from a to console
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mov cl,conout
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mov dl,al ;character to send
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call bdos ;send character
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ret
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;
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crlf:
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;send carriage return line feed
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mov al,cr ;carriage return
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call putchr
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mov al,lf ;line feed
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call putchr
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ret
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;
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print:
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;print the buffer addressed by dx until $
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push dx
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call crlf
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pop dx ;new line
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mov cl,pstring
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call bdos ;print the string
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ret
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;
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readcom:
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;read the next command line to the conbuf
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mov dx,offset prompt
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call print ;command?
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mov cl,rstring
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mov dx,offset conbuf
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call bdos ;read command line
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; command line is present, scan it
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mov ax,0 ;start with 0000
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mov bx,offset conlin
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readc: mov dl,[bx] ;next command character
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inc bx ;to next command position
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mov dh,0 ;zero high byte for add
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or dl,dl ;check for end of command
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jnz getnum
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ret
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; not zero, numeric?
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getnum:
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sub dl,'0'
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cmp dl,10 ;carry if numeric
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jnb endrd
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mov cl,10
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mul cl ;multipy accumulator by 10
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add ax,dx ;+digit
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jmps readc ;for another char
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endrd:
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; end of read, restore value in a and return value in bx
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mov dx,ax ;return value in DX
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mov al,-1[bx]
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cmp al,'a' ;check for lower case
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jnb transl
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ret
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transl: and al,5fH ;translate to upper case
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ret
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;
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;
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; Template for Page 0 of Data Group
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; Contains default FCB and DMA buffer
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;
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dseg
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org 05ch
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fcb rb 33 ;default file control block
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ranrec rw 1 ;random record position
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ranovf rb 1 ;high order (overflow) byte
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buff rb 128 ;default DMA buffer
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;
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; string data area for console messages
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badver db 'sorry, you need cp/m version 2$'
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nospace db 'no directory space$'
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datmsg db 'type data: $'
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errmsg db 'error, try again.$'
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prompt db 'next command? $'
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;
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;
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; fixed and variable data area
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;
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conbuf db conlen ;length of console buffer
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consiz rs 1 ;resulting size after read
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conlin rs 32 ;length 32 buffer
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conlen equ offset $ - offset consiz
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;
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rs 31 ;16 level stack
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stack rb 1
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db 0 ;end byte for GENCMD
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end
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x,ax ;return value in DX
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mov al,-1[bx]
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cmp |