Programmer 7500

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Text File | 1987-12-23 | 16.1 KB | 394 lines

TOS Saved during Task switching. ENTRY Jumped to during multitasking. LINK Points to next task in the circular queue SP0 Empty parameter stack for this task. RP0 Empty return stack for this task. DP Size of dictionary. Next available location. #OUT Number of characters sent since last CR. #LINE Number of CR's sent since last page. OFFSET Added to all block references. BASE The current numeric base for number input output. HLD Points to a converted character during numeric output. FILE Allows printing of one file while editing another. IN-FILE Allows printing of one file while editing another. PRINTING indicates whether printing is enabled. YDP Size of headers. Next available location. EMIT Sends a character to the output device. SCR Holds the screen number last listed or edited. PRIOR Points to the last vocabulary that was searched. DPL The decimal point location for number input. WARNING Checked by WARN for duplicate warnings. R# The cursor position during editing. HLD Points to a converted character during numeric output. LAST Points to the name of the most recently CREATEd word. CSP Used for compile time error checking. CURRENT New words are added to the CURRENT vocabulary. #VOCS The number of elements in the search order array. CONTEXT The array specifying the search order. 'TIB Points to characters entered by user. WIDTH Number of characters to keep in name field. VOC-LINK Points to the most recently defined vocabulary. BLK If non-zero, the block number we are interpreting. >IN Number of characters interpreted so far. SPAN Number of characters input by EXPECT. #TIB Used by WORD, when interpreting from the terminal. END? True if input stream exhausted, else false. BL BS BELL Names for BLank, BackSpace, and BELL CAPS If true, then convert names to upper case FILL FILL the string starting at start-addr for count bytes with the character char. Both BLANK and ERASE are special cases of FILL. ERASE Fill the string with zeros BLANK Fill the string with blanks COUNT Given the address on the stack, returns the address plus one and the byte at that address. Useful for strings. LENGTH Given the address on the stack, returns the address plus two and the two byte contents of the address. MOVE Move the specified bytes without overlapping. >UPPER subroutine which converts character in AX to upper case. UPC Convert a Char to upper Case UPPER Take the string at the specified address and convert it to upper case. It converts the string in place, so be sure to make a copy of the original if you need to use it later. HERE Return the address of the top of the dictionary PAD Floating Temporary Storage area. -TRAILING Return the address and length of the given string ignoring trailing blanks. COMP This performs a string compare. If the two strings are equal, then COMPARE returns 0. If the two strings differ, then COMPARE returns -1 or +1. -1 is returned if string 1 is less than string 2. +1 is returned if string 1 is greater than string 2. All comparisons are relative to ASCII order. CAPS-COMP The code on this screen handles the case where case is not significant. Each character is converted to upper case before the comparison is made. Thus, lower case a and upper case A are considered identical. COMPARE Performs a string compare. If CAPS is true, characters from both strings are converted to upper case before comparing. OSF Operating Sys call in progress flag. FCDOS called by other assembler code to do INT 21 (DOS call). BP and SI are the critical FORTH registers. Create is used here to force force lable into target dictionary. OSF is set during the DOS call, can be tested by interrupt routines which call non-reentrant DOS functions. XFDOS : call INT 21 with most any reg combination used. ?CS: : leave FORTH CS on stack @L : ( seg adr - n ) load word long C@L : ( seg adr - byt) char load long C!L : ( byt seg adr -) char store long !L : ( n seg adr -- ) word store long BDOS Load up the registers and do a DOS system call. return the result placed in the A register on the stack. (KEY?) Returns true if the user pressed a key, otherwise false. (KEY) Pauses until a key is ready, and returns it on the stack. (EMIT) Sends the character to the terminal. CMOVEL : ( sseg sptr dseg dptr cnt ) move char block long. YSTART : if non-zero, ptr to start of headers after dictionary. Used to set DP in this case. YSEG : SEG for header segment MEMCHK : abort with memory error message if true DOSVER : get DOS version number SETYSEG : move headers after dictionary to their own segment. Reserves 100k space (DOS 2.x required). Copies headers to the alloted space Probably should have YALLOT also for completeness. Wasn't needed very often. KEY? Usually set to (KEY?), to sense keyboard status. KEY Usually set to (KEY) to get a character from the user. CR Typically set to CRLF, above. PR-STAT Return printer status, if implemented, else TRUE (PRINT) The value of the DEFERRED word EMIT when you want to send a character to the printer. (EMIT) sends a character to both the console and the printer. CRLF Sends a carriage return line feed sequence. TYPE Display the given string on the terminal. SPACE Send a space to the terminal SPACES Send a set of spaces to the terminal BACKSPACES Send a set of Backspaces to the terminal. BEEP Ring the bell on the terminal BS-IN If at beginning of line, beep, otherwise back up 1. (DEL-IN) If at beginning of line, beep, otherwise back up and erase 1. BACK-UP Wipe out the current line by overwriting it with spaces. RES-IN Reset the system to a relatively clean state. P-IN Toggle the printer on or off CR-IN Finish input and remember the number of chars in SPAN (CHAR) Process an ordinary character by appending it to the buffer. CHAR is usually (CHAR). Executed for most characters. DEL-IN is usually (DEL-IN). Executed for delete characters. CC Points to current control character table. CC-FORTH Handle each control character as a special case. This generates an execution array which is indexed into by EXPECT to do the right thing when it receives a control character. EXPECT Get a string from the terminal and place it in the buffer provided. Performs a certain amount of line editing. Saves the number of characters input in the Variable SPAN. Processes control characters per the array pointed to by CC. TIB Leaves address of text input buffer. QUERY Get more input from the user and place it at TIB. These variables are used by the BLOCK IO part of the system. Unlike FIG Forth the buffers are managed in a true least recently used scheme. The are maintained in memory as an array of 8 byte entries, whose format is defined at left. Whenever a BLOCK is referenced its pointer is moved to the head of the array, so the most recently used buffer is first. Thus multiple references are very fast. Also we have eliminated the need for a null at the end of each BLOCK buffer so that the size of a buffer is now exactly 1024 bytes. The format of entries in the buffer-pointer array is: 0-1 is Block Number 2-3 is Pointer to File 4-5 is Address of Buffer 6-7 is Update Flag BUFFER# Return the address the the nth buffer pointer. >END Return a pointer to just past the last buffer packet. >UPDATE Return a pointer to the update flag. READ-BLOCK performs physical read. WRITE-BLOCK performs physical write. .FILE (S adr -- ) print filename in fcb at adr. FILE? (S -- ) print name of current file. SWITCH exchange in-file and file. DOS vocabulary for native file system interface words. !FILES sets both file pointers to the specified file. DISK-ABORT (S fcb a n -- ) print error message and file name. ?DISK-ERROR (S fcb n -- ) report disk error. CLR-FCB Initialize the specified FCB. SET-DMA CP/M system call to set dma address RECORD# Pointer to the specified Ramdom Record MAXREC# Pointer to the largest record allowed IN-RANGE Makes sure that the Random Record is within Range. Issues error message if it isn't. REC-READ Do a Random Access read REC-WRITE Do a Random Access write SET-IO common set-up for file reads and writes. FILE-READ read 1024 bytes from a file. FILE-WRITE write 1024 bytes to a file. FILE-IO set block read and writes to use files. CREATE SOURCE-BUF 1026 ALLOT SOURCE-BUF 1026 ERASE : GET-BLOCK (S BLK# -- ) [ DOS ] MYBUFFER (SET-DMA) IN-FCB @ >R R@ RECORD# ! B/REC R@ BREC# ! R> 33 BDOS ; ( .EXE file support 12:19 04/22/86 ) XCKSUM checksums a block of memory using word addition ( cnt must be even ) SUVEC startup vector, for a long jump to HEX 100 to set up CS correctly. Currently the .EXE header has CS set at 0FFF0h which fakes out the loader to set CS to the same as the Program Sement Prefix. This makes the long jump unnecessary, but we put it in so we could easily make the .EXE header more conventional. SEXE entry point specified by .EXE header. Sets the seg part of SUVEC, moves FORTH headers up to seg after DS (YSEG), does long jump thru SUVEC to start system. EHMT empty .EXE header. Entries 0Eh and 16h are SS and CS, set to -10h, somewhat questionable. If they are changed, 10h and 14h must be changed to compensate. CAPACITY The number of blocks in the current file LATEST? For increased performance we first check to see if the block we want is the very first one in the list. If it is return the buffer address and false, and exit from the word that called us, namely ABSENT?. Otherwise we return as though nothing had happened. ABSENT? Search through the block/buffer list for a match. If it is found, bring the block packet to the top of the list and return a false flag and the address of the buffer. If the block is not found, return true, indicating it is absent, and the second parameter is garbage. UPDATE Mark the most recently used buffer as modified. DISCARD Mark the most recently used buffer as unread. MISSING Writes the least recently used buffer to disk if it was modified, and moves all of the buffer pointers down by one, making the first one available for the new block. It then assigns the newly available buffer to the new block. (BUFFER) assigns a buffer to the specified block in the given file. No disk read is performed. Leaves the buffer address. BUFFER assigns a buffer to the specified block. No disk read is performed. Leaves the buffer address. (BLOCK) Leaves the address of a buffer containing the given block in the given file. Reads the disk if necessary. BLOCK Leaves the address of a buffer containing the given block. Reads the disk if necessary. IN-BLOCK like BLOCK, but for the IN-FILE. EMPTY-BUFFERS First wipe out the data in the buffers. Next initialize the buffer pointers to point to the right addresses in memory and set all of the update flags to unmodified. SAVE-BUFFERS Write back all of the updated buffers to disk, and mark them as unmodified. Use this whenever you are worried about crashing or losing data. FLUSH Save and empties the buffers. Used for changing disks. The phrase " 0 BLOCK DROP " is a kludge for CP/M. Some systems do extra buffering in the BIOS, and you must access a new block to be sure the old one is actually written to disk VIEW# returns address of the view# field for this file. FILE-SIZE Return the size of the file in records. DOS-ERR? Returns true if a DOS error occurred. OPEN-FILE Open the current file and tell user if you can't. Determine the size of the file and save it for error check. DOS-FCB The address where the DOS puts a parsed FCB DEFAULT Opens the default file per the execute line. Move the already parsed file control block into FCB1, and open the file. This does nothing if no file was given. (LOAD) Load the screen number that is on the stack. The input stream is diverted from the terminal to the disk. LOAD Interpret a screen as if it were type in . DIGIT Returns a flag indicating whether or not the character is a valid digit in the given base. If so, returns converted value and true, otherwise returns char and false. DOUBLE? Returns non-zero if period was encountered. CONVERT Starting with the unsigned double number ud1 and the string at adr1, convert the string to a number in the current base. Leave result and address of unconvertable digit on stack. (NUMBER?) Given a string containing at least one digit, convert it to a number. NUMBER? Convert the count delimited string at addr to a double number. NUMBER? takes into account a leading minus sign, and stores a pointer to the last delimiter in DPL. The string must end with a blank. Leaves a true flag if successful. (NUMBER) Convert the count delimited string at addr to a double number. (NUMBER) takes into account a leading minus sign, and stores a pointer to the last period in DPL. Note the string must end with a blank or an error message is issued. NUMBER Convert a string to a number. Normally (NUMBER) HOLD Save the char for numeric output later. <# Start numeric conversion. #> Terminate numeric conversion. SIGN If n1 is negative insert a minus sign into the string. # Convert a single digit in the current base. #S Convert a number until it is finished. HEX All subsequent numeric IO will be in Hexadecimal. DECIMAL All subsequent numeric IO will be in Decimal. OCTAL All subsequent numeric IO will be in Octal. (U.) Convert an unsigned 16 bit number to a string. U. Output as an unsigned single number with trailing space. U.R Output as an unsigned single number right justified. (.) Convert a signed 16 bit number to a string. . Output as a signed single number with a trailing space. .R Output as a signed single number right justified. (UD.) Convert an unsigned double number to a string. UD. Output as an unsigned double number with a trailing space UD.R Output as an unsigned double number right justified. (D.) Convert a signed double number to a string. D. Output as a signed double number with a trailing space. D.R Output as a signed double number right justified. DONE A common exit routine for SKIP and SCAN. SKIP Given the address and length of a string, and a character to look for, run through the string while we continue to find the character. Leave the address of the mismatch and the length of the remaining string. SCAN Given the address and length of a string, and a character to look for, run through the string until we find the character. Leave the address of the match and the length of the remaining string. /STRING Index into the string by n. Returns addr+n and len-n. PLACE Move the characters at from to to with a preceding length byte of len. (SOURCE) Returns the string to be scanned. This is the default value of the deferred word SOURCE. SOURCE Return a string from the current input stream. PARSE-WORD Scan the input stream until char is encountered. Skip over leading chars. Update >IN pointer. Leaves the address and length of the enclosed string. PARSE Scan the input stream until char is encountered. Update >IN pointer. Leaves the address and length of the enclosed string. 'WORD Leaves the same address as WORD. In this system, 'WORD is the same as HERE. WORD Parse the input stream for char and return a count delimited string at here. Note there is always a blank following it.