****************************************************************
*                                                              *
*                                                              *
*                 *****   ****    *****   *****                *
*                 *       *   *     *       *                  *
*                 *       *   *     *       *                  *
*                 ***     *   *     *       *                  *
*                 *       *   *     *       *                  *
*                 *       *   *     *       *                  *
*                 *****   ****    *****     *                  *
*                                                              *
*                                                              *
*                    VDM--BASED TEXT EDITOR                    *
*                                                              *
*                       EDIT 2.0 (MOD 0)                       *
*                       JANUARY 30, 1983                       *
*                                                              *
*                      COPYRIGHT (C) 1983                      *
*                   PROTEUS SOFTWARE LIBRARY                   *
*                                                              *
*                                                              *
****************************************************************
*                                                              *
*       EDIT sfile[<A>][,ofile[<A>]][,highmemory]              *
*                                                              *
*       where the "<A>" must appear exactly as shown           *
*       if the input (source) file is an ALS8-format           *
*       file or if the output file is to be written            *
*       in ALS8 format.  If only one file is specified         *
*       then the ofile will default to the same as sfile       *
*       and will be written in the same format.                *
*                                                              *
****************************************************************
 TITL EDIT
 ASCF 0
 IFLS
*
 ORG 100H
 XEQ GPRAM
*
 COPY NPTDEFS
SPACE EQU ' '
YES EQU -1
NO EQU 0
SUTILFN EQU 2  SUTIL'S FILE NUMBER (USED IN INSERT FILE)
*
****************************************************************
*
START JMP REENT  Re-entry point
EDIT LXI D,SFILE  DE and HL point to infile's name
 LXI H,SFILE
 MVI A,PSOP+40H  open the file
 CALL PSCAN
 MOV A,E  get the file # or error #
 JC OER1  error
 STA SFNUM  save the source file's number
 LXI D,GPRAM
*
NEXTL PUSH D  DE= address of next free byte
 XCHG
 LXI B,512+40  leave this much room
 DAD B
 LXI D,EOSP  DE-> highest address editor is allowed to use
 CALL DCMP  compare EOSP with HL
 POP D  DE= next free byte again
 JC ERTOB  Too big (HL>EOSP)
 LDA SALS8  Is source file in ALS8 format?
 CPI YES
 JZ NXTL1  Yes. We don't have to add length bytes.
 PUSH D  Save position where length byte should go.
 INX D  Leave room for it.
*
NXTL1 LDA SFNUM  Get file #.
 LXI B,255  Sets B=0, C=255 (max read count)
 MVI L,CR  line delimiter
 CALL SYS
 DB DRDOP  delimited read
 JMP LOAD  eof (hopefully)
 LDA SALS8  Was it ALS8-type?
 CPI YES
 JZ NEXTL  Yes. No problem.
 POP H  HL-> where length byte should go.
 XRA A  Set A=0.
 SUB C  Compute length (=-C)
 MOV M,A  Store it.
 JMP NEXTL  Read next line.
*
LOAD PUSH PSW
 LDA SFNUM
 CALL SYS
 DB CLOOP
 CALL RER1
 POP PSW
 CPI EREOF  EOF?
 JNZ RER1  READ ERROR
 LDA SALS8
 CPI YES
 JZ LOAD0  It was ALS8, so no problem.
 POP D  Otherwise D is on the stack.
*
LOAD0 DCX D  This brings D back to last thing loaded.
 PUSH D  LAST ADDRESS LOADED
 CALL OUST
 DW 0A0DH
 ASC "EDIT 2.0 (MOD 0)"
 DW 0A0DH
 ASC "COPYRIGHT (C) 1983"
 DW 0A0DH
 ASC "PROTEUS SOFTWARE LIBRARY"
 DW 0A0DH
 ASC "********"
 DW 0A0DH
 ASC "Last load addr: "
 DB 0
*
 POP H
 PUSH H
 SHLD EFP
 CALL OUT16  OUTPUT LAST ADDRESS
 CALL OUST
 DW 0A0DH
 ASC "Load count: "
 DB 0
*
 POP D
 LHLD BFP
 MOV A,E
 SUB L
 MOV L,A
 MOV A,D
 SBB H
 MOV H,A
 INX H
 PUSH H
 CALL OUT16  LOAD COUNT
*
*   CHECK THE FILE
*
 CALL OUST
 DW 0A0DH
 ASC "End of file at: "
 DB 0
 LXI D,EFP
 POP H
 MOV A,H
 ORA L
 LHLD BFP
 JZ STEND  NO BYTES LOADED
 LXI B,0
*
CKLOP MOV A,M  GET COUNT
 DCR A
 MOV C,A
 JZ EFRPT
 DAD B
 MOV A,M
 CPI 0DH
 JNZ RPERR
 INX H
 CALL DCMP
 JC STEND
 JNZ CKLOP
STEND MVI M,1
 JMP EFRPT
*
*
*  REPORT BAD FILE
*
RPERR PUSH H
 CALL OUST
 DW 0A0DH
 DW 0A0DH
 ASC "Edit abort...file error"
 ASC " at address: "
 DB 0
 POP H
 CALL OUT16
 CALL OUST
 DW 0A0DH
 DB 0
 JMP EXIT
*
*
EFRPT SHLD EFP
 CALL OUT16
*
*  CHECK FOR FREE SPACE
*
 XCHG
 LHLD EOSP
 MOV A,L
 SUB E
 MOV L,A
 MOV A,H
 SBB D
 MOV H,A
 PUSH H
 CALL OUST
 DW 0A0DH
 ASC "Bytes free: "
 DB 0
 POP H
 CALL OUT16
*
STRTED CALL OUST  Start editing.
 DW 0A0DH
 DW 0A0DH
 ASC "C/R to continue"
 DB 0
*
EWAIT CALL CONIN
 CPI 0DH
 JNZ EWAIT
 LXI SP,AREA+18
 LHLD BFP
 LXI D,EFP
 CALL DCMP
 JC OER1
 JNZ EDIT1
*
*  NULL FILE INITIALIZE IT
*
 MVI M,2
 INX H
 MVI M,CR
 INX H
 MVI M,1
 SHLD EFP
*