BASIC PRECOMPILER User`s Manual
Contents
1. Error messages 5 Adapting to your system Appendix Sri een ane BASIC PRECOMPILER User s Manual 1 INTRODUCTION Technical Systems Consultants BASIC PRECOMPILER PC and EXTENDED BASIC PRECOMPILER XPC are designed to give the BASIC user greater flexibility in writing programs easier to read programs smaller compiled files precompilers accept BASIC source files and convert to BAsic Compile files BAC similar to the COMPILE command in BASIC This should not be confused with BASIC compilers that generate machine language code because PC and XPC generate code that can only be used with BASIC This is the manual of the precompiler for both BASIC and EXTENDED BASIC and for both the 6800 and 6809 PC and XPC execute in two passes and will accept any size file on the disk for input as long as enough memory is available for the symbol table Two types of output can be generated The first one is a source listing of the basic program complete with line numbered statements and any error messages The second is the compiled version of the program ready to be executed by BASIC It is assumed that the reader is familiar with BASIC so detailed programming examples are not given nor is the syntax of the BASIC language explained BASIC PRECOMPILER User s Manual 1 1 Conventions As in the BASIC User s manuals the following conventions will be used The statement or comman2. before starting For example PC PROGI BAS P DELETE OLD BINARY Y N If N is typed after the prompt PC will quit and return to FLEX If Y BASIC PRECOMPILER User s Manual is typed the file will be deleted and PC will continue on its way If anything else is typed you will be prompted again for either Y or N Optionally one may include compiler options on the command line The list of options must start with a plus sign may not have any imbedded spaces and contain the following letters in any order B Do not create the binary file No binary file will be created even if a binary file name is specified This is useful when compiling a program to check for any syntax errors or for a listing of the program L Suppress the source listing If not specified the compiler will print each line as it is read in pass two lines containing errors will automatically be printed regardless of whether or not the option is specified Also imbedding a compiler LIS or NOL option into the source will turn on or off the source listing 5 5 has no meaning whatsoever It is included just to be compatible with the ASMB command N Turn off line numbers By default line numbers are printed at the beginning of each logical line But if the source program already has line numbers like a normal basic program more line numbers would only be confusing Y Yes go ahead and delete the binary file If binary 15 being generated and the
3. Each variable requires the number of characters in the variable name plus 1 byte plus 8 bytes for double precision 4 bytes for single precision or 4 bytes for strings arrays and user defined functions The second type of errors are source code errors UNBALANCED PARENS An expression has unbalanced parentheses UNRECOGNIZABLE CHARACTER character was seen that has no meaning to the compilers MISSING QUOTE closing quote was missing from a string constant Since strings cannot cross physical line boundaries if an end of line is seen before a closing quote this error is generated DUPLICATE LINE LABEL Two lines have the same label UNDEFINED LINE LABEL A reference to a label that does not exist was made BAD CONSTANT An error was detected when trying to convert an ASCII number to binary The number could be too large too small or contain an illegal character DUMMY VARIABLE NAME TOO LONG Dummy variable names can be a maximum of 30 characters long ILLEGAL SCALE FACTOR This error is in XPC only The SCALE factor was too large too 10 BASIC PRECOMPILER User s Manual small or the SCALE option was not on the first line of the original source file NESTED LIB FILES NOT ALLOWED A file being read in via LIB had a LIB option in it LINE TOO LONG One of two things can cause this error If the error occurred and went immediately back to FLEX then the input source was longer than 255 characters including c
4. compiled as one logical line even though it is split across two physical lines Notice that REMark statement after the THEN portion would BASIC PRECOMPILER User s Manual cause the ELSE statement to be ignored since REMarks stop at the end of the LOGICAL line The next logical line is the line that begins with an asterisk in column one This is a REMark line and is ignored by the compiler The last logical line consists of seven physical lines starting with the FOR statement and ending with the NEXT statement Even though seven physical lines are involved only three basic statements are used If more than one statement is logical line the statement must be seperated by either a colon or a backslash A backslash carriage return does not act as statement terminator 3 4 Compiler Options As the above example shows any line that starts in column one with a separator is considered to be a comment line In most cases a comment line 15 ignored by PC and XPC If the comment starts with a dollar sign in column one then the line is checked to see if it is a compiler option line The following options are recognized TTL lt string gt TTL sets the program title to lt string gt The title may be 0 to 35 characters long If the lt string gt is longer anything past the 35th character is ignored The title string is printed left justified on the same line as the date and compiler name STTL lt string gt STTL sets
5. BASIC Precompiler Users Manual COPYRIGHT 1979 by Technical Systems Consultants Inc 111 Providence Road Chapel Hill North Carolina 27514 All Rights Reserved COPYRIGHT INFORMATION This entire manual is provided for the personal use and enjoyment of the purchaser Its contents are copyrighted by Technical Systems Consultants Inc and reproduction in whole or in part by any means is prohibited Use of this program or any part thereof for any purpose other than single end use by the purchaser is prohibited DISCLAIMER The supplied software is intended for use only as described in this manual Use of undocumented features or parameters may cause unpredictable results for which Technical Systems Consultants Inc cannot assume responsibility Although every effort has been made to make the supplied software and its documentation as accurate and functional as possible Technical Systems Consultants Inc will not assume responsibility for any damages incurred or generated by such material Technical Systems Consultants Inc reserves the right to make changes in such material at any time without notice Index 1 Introduction 1 1 conventions 1 2 definitions 2 Getting the system started 3 Features sis asia ere ox 3 1 variable names 3 2 line labels 3 3 continuation of lines 3 4 compiler options 4
6. ave a LIB option in it That is LIB options cannot be nested or recursive lt n gt The SCALE command is available only in XPC It sets the SCALE factor to lt n gt where 0 lt lt 6 The SCALE option must be the first line of the original source file If an error occurs in the SCALE option the SCALE factor is set to zero See the EXTENDED BASIC User s manual for use of the SCALE factor Some examples using options are SCALE 3 set scale factor to 3 on the first line TTL this is the title up to 35 chr long STTL this is the sub title up to 80 characters long PAG perform a page eject SPC 3 skip 3 lines NOL turn listing off for FILE1 LIB FILE1 read FILE1 LIS Turn listing back on for FILE2 LIB FILE2 read FILE2 END BASIC PRECOMPILER User s Manual 4 Error Messages There are two types of error messages that can be generated by the compilers The first type is from errors found on the command line calling PC or XPC from FLEX The errors are ILLEGAL OPTION SPECIFIED An unknown option character was found after the plus sign ILLEGAL FILE NAME A file name was specified that was not in the standard FLEX format MEMORY OVERFLOW Not enough memory was available to insert a symbol into the symbol table area This can mean that the program has too many symbols to compile or that the MEMEND value in FLEX was set too low Each program label requires the number of characters in the label plus 5 bytes for flags
7. d being described will be printed in capital letters Angle brackets lt gt will be used to enclose essential components of the statement Square brackets will be used to enclose optional components lt essiental item gt optional item 1 2 Definitions LOGICAL LINE A logical line in BASIC can consist of one or more physical lines It may also consist of one or more basic statements separated by either a back slash or a colon PHYSICAL LINE A physical line is defined to be one line on a terminal ending with a carriage return It also can be thought of as one line in the editor LETTERS The set of letters consists of the characters A through Z and through z The underscore character _ is valid as a letter also NUMBERS The set of numbers consists of the characters 0 through 9 HEXADECIMAL NUMBERS Hexadecimal numbers will start with a dollar sign and be followed by four characters from the set of numbers and the set of letters A to F SEPARATORS The set of separators consists of any character that is not a letter number or an underscore BASIC PRECOMPILER User s Manual 2 GETTING THE SYSTEM STARTED Since there are not any built in editing functions in the compilers you must have a previous created source file on disk before using PC or XPC The source must must be a standard FLEX source file which is simply textual lines terminated with a carriage return There sho
8. ess gt lt transfer address gt and you have a new version of the precompiler The following table defines the start end and transfer addresses for each precompiler precompiler start end transfer address address address PC for 6800 0002 12FF 0100 XPC for 6800 0002 16FF 0100 PC for 6809 0000 12FF 0000 XPC for 6809 0000 16FF 0000 2755 BASIC PRECOMPILER User s Manual Appendix The following is a list of all keywords defined in PC ABS GOSUB AND GOTO PTR AS HEX PUT ASC IF READ ATN INPUT RECORD CHAIN INT REM CHR KILL RENAME CLOSE LEFT RESTORE COS LEN RESUME CVT F LET RETURN CVTF LINE RIGHT DATA LOG RND DEF LSET RSET DIM MID SGN ELSE NEW SIN END NEXT SPC ERL NOT SQR ERR OLD STEP ERROR ON STOP EXEC OPEN STR EXP OR TAB FIELD PEEK TAN FN PI THEN FOR POKE TO FRE POS USR GET PRINT VAL 14 BASIC PRECOMPILER User s Manual The following is a list of all keywords defined in XPC ABS AND AS ASC ATN CHAIN CHR CLOSE COS CVT 2 CVT F CVT2 CVTF DATA DATE DEF DIGITS DIM DPEEK DPOKE ELSE END ERL ERR ERROR EXEC EXP FIELD FN FOR FRE GET GOSUB GOTO HEX IF INCH INPUT INSTR INT KILL LEFT LEN LET LINE LOG LSET MID NEW NEXT NOT OLD ON OPEN POS PRINT PTR PUT READ RECORD REM RENAME RESTORE RESUME RETURN RIGHT RND RSET SGN SIN SPC SQR STEP STOP STR SWAP TAB TAN THEN TO USING USR VAL
9. file already exists then specifying Y will over ride the prompt to delete the file Some examples PC PROG LY no listing delete old binary PC PROGI BAS NB listing on no line numbers or binary PC PROG 51 listing binary on T BAC the work drive automatically delete existing binary file The compilers do not have a built in method to output to hardcopy device However this operation is available through I 0 redirection in FLEX For example P PC PROG B would cause the listing to be sent to whatever device was defined by the P command in FLEX For further details of the P command see the FLEX User s Manual and the FLEX Advanced Programmer s Guide BASIC PRECOMPILER User s Manual 3 FEATURES Four things stand out as the main features of PC and XPC They are 1 unlimited length variable names 2 unlimited length label names 3 continuing logical lines across physical line boundaries 4 pagination control for listings Each feature will be discussed in detail below 3 1 Variable Names Variable names may be of any length and may contain letters numbers and the underscore character The name cannot be a keyword see appendix A for list of keywords the first character must be a letter or an underscore and the name must be terminated by a blank or separator Also the name cannot start with the letters FN unless it is call to or definition of a USER DEFINED function Lowe
10. ments must start in column two or beyond Some examples are THIS 15 LABEL REM THIS IS A REMARK STATEMENT WITH LABEL 10007 REM THAT WAS THE LABEL 1000 THIS IS LABEL WITHOUT A STATEMENT 0000 REM NOTE THAT 0000 IS A LEGAL LABEL NAME GOTO 0000 REM IS A VALID STATEMENT BUT GOTO0000 REM DEFINES A VARIABLE 60 00000 3 3 Continuation of Lines PC and XPC allow BASIC lines logical lines to be split across physical line boundaries or in other words a logical line consists of one or more physical lines do so just place a backslash before the carriage return PC and XPC treat the back slash carriage return on continued lines simply as a blank This means that variable names and keywords cannot be continued onto the next line since the blank is a separator Also the total length of the logical line must not exceed 255 characters or the error message LINE TOO LONG will be generated It should be noted that multiple spaces are ignored except inside of strings where they are significant For example IF DELTA lt GAMMA THEN PRINT DELTA DELTA lt CR gt ELSE PRINT GAMMA GAMMA lt CR gt DEFINE RECORD 1 0 BUFFER FOR I 0 TO NUMBER ELEMENTS FIELD 1 I ELEMENT SIZE AS G lt CR gt 15 AS FIRST NAME I lt CR gt 15 AS LAST NAME I lt CR gt 09 AS SOC SEC _NU I lt CR gt 02 AS INDEX T lt CR gt NEXT I lt CR gt In the first line of the example the IF THEN ELSE statement is
11. ontinued lines If the error message was printed and the compiler continued on to the next line then the binary generated for that line was greater than 255 bytes 11 BASIC PRECOMPILER User s Manual 5 Adapting to your system Since the precompilers run under the FLEX operating system there is very little adapting to be done None the less there are three constants that the user can change 1 the page eject string that is sent to a printer 2 the number of lines on a page and 3 the number of blank lines at the top of a page The page eject string is sent to the printer to position the print head to the top of the next page The eject string consists of a carriage return line feed form feed and three null characters terminated by an ETX 0004 character The user may change the first six characters to anything else as long as the string is no more than six characters long and is terminated by the ETX character One can disable the page eject string completely by placing an ETX as the first character of the string The page size is the number of lines to be printed on a page before a page eject is to be performed Initially this is set to 55 lines That is the page is assumed to be 55 lines long PLUS the number of lines defined by the margin count PLUS five lines for the page heading The margin count is initially set to 3 This means after the page eject is performed three blank lines are printed Then the title and s
12. r case letters are automatically mapped into upper case therefore the name lower is the same as the name LOWER Some examples of variable names are THIS 15 VARIABLE NAME SO 15 THIS THIS 15 STRING VARIABLES SO IS THIS this 15 too FUNCTION IS FUNCTION NAME THIS 15 AN INTEGER VARIABLES SO IS THIS THIS 15 A DUPLICATE NAME this 15 duplicate name Some illegal variable names are 1 CANNOT START A VARIABLE NAME OCANNOT_ START A VARIABLE EITHER CLOSE variable names cannot be keywords Dummy variable names are an exception They are limited to 30 characters length Since the compiler must remember the dummy variable when defining the user defined function a buffer of 30 characters is set aside for the name This is not really a restriction since it is common practice to use a single character to define the dummy variable For example DEF FNCTION1 X SQR X X Defines function FNCTION1 with dummy variable BASIC PRECOMPILER User s Manual 3 2 Line Labels BASIC normally requires an integer line number on every source line of the program PC and XPC on the other hand only require a label on a line that program control will be transferred to Also the label need not be an integer it can be any contiguous series of characters consisting of letters numbers and underscores Any other character terminates the label name All statement labels must begin in column one and state
13. the program sub title to lt string gt The sub title may be 0 to 80 characters long If the lt string gt is longer than 80 characters anything past the 80th charcter is ignored sub title string is printed left justified under the title line PAG The PAG option causes a page eject to occur Normally a page eject is performed every 55 lines but by using the PAG option one can cause a premature page eject See also Adapting to Your System SPC lt n gt lt m gt The SPC command causes lt n gt blank lines to be inserted into the listing Optionally the lt m gt parameter be specified which 15 a keep count If there are less than lt m gt lines left on the then instead of spacing lt n gt lines a page eject is performed and processing of the space command is terminated This is useful to prevent a block of lines from being split across a page LIS NOL BASIC PRECOMPILER User s Manual LIS is used to turn on the listing option If the list option is already on then the LIS option is ignored NOL is used to turn off the listing option If the list option is already turned off then the NOL option is ignored LIB lt file name gt SCALE The LIB option tells the compiler to start reading the source from an alternate file The lt file name gt should be in the normal FLEX format and will have the same defaults as the source file name did on the command line A file that is being LIBed in cannot h
14. ub title lines are printed followed by three blank lines Then 55 lines of source followed by a page eject and so on and so forth It should be noted that printing the page eject string is suppressed if output is going to the terminal So if you are listing a program at a terminal that understands form feeds the page eject won t clear the screen on every new page The precompilers use as end of memory the address MEMEND defined in FLEX As the precompilers read in source labels and variable names are put in a symbol table The symbol table starts at the end of the program and grows towards the end of memory As a consequence any other program to be kept in memory with the precompilers must be higher read greater than the address stored at MEMEND The address of MEMEND in FLEX 1 0 and FLEX 2 0 is AC2B and MEMEND in FLEX 9 0 is CC2B For all versions of the precompiler the constants are located at EJECT STRING 0002 PAGE SIZE 0009 MARGIN COUNT 000 To change of these constants do the following load the precompiler into memory with FLEX s GET command go into your systems monitor using FLEX s MON command 12 BASIC PRECOMPILER User s Manual change the constant s go back into FLEX at the warm start entry point ADO3 for FLEX 1 0 and FLEX 2 0 003 for FLEX 9 0 save the precompiler back out on the disk using FLEX s SAVE command where the syntax is SAVE lt file name gt lt start address gt lt end addr
15. uld be no control characters in the source file except for the carriage return THE FLEX COMMAND LINE The syntax for calling PC or XPC is as follows PC lt source file gt lt compile file gt lt options gt or XPC lt source file gt lt compile file gt lt options gt Where all file names are standard FLEX file names and default to the current working drive The lt source file gt is a previously edited file containing the BASIC source lines lt compile file gt is optionally specified as the name of a file to contain the result of the compilation and lt options gt is a list of options to be invoked when the compiler is called The source file by default has an extension of TXT as if it were generated by the Text Editor Optionally one can specify a different extension ie BAS or a drive other than the working drive ie 1 PROG by just including it in the file name For example PC PROG will default to PROG TXT on the working drive PC PROG BAS 1 over rides all filename defaults The binary file if not specified defaults to the same name as the source file but with the BAC extension Optionally one may specify a different name by just including it in the command line For example PC PROGI BAS P will use as source PROG1 BAS on the working drive and write the binary to P BAC also on the working drive If the file P BAC already exists on the working drive PC will ask the user if the file should be deleted
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