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Portfolio BASIC, version 2.1 (c) 1990 BJ Gleason by BJ Gleason, The American University INTRODUCTION PBASIC is a simple BASIC interpreter. It only requires 30k of disk space and about 43k of memory to run. PBASIC is a batch oriented interpreter. It will also interact with the built-in editor for program development. PBASIC was one of the winners in the Compuserve/ Portfolio Conference Programming Contest, 1990. A NOTE FROM THE AUTHOR As of this release, PBASIC is only going to upgraded for bug fixes for a while. This interpreter started out as a "see if I can do it project." Because writing it and upgrading it is so much fun, it has kept me from doing some of my other work. Due in large part to the positive encouragement of the people who have used it, I have added floating point, arrays, virtual screen manipulation and printer support for this version. The next step will be strings and files, but they will require a bit of thought on implementation design. As it stands, the current design is a bit of a hack (read that as totally), and is getting a bit awkward to work with. Over the next few months, I will maintain and release new versions of 2.0 as the occasion merits. I will still be very receptive to your ideas, and look forward to talking to you. Some of the things I am working on include: strings, files, making the interpreter a .RUN file so more memory is available, and converting to code to C++. A number of considerate users have offered their help. If you have an interesting application that you have developed in PBASIC, I will be more than happy to distribute your code in future releases. Please make sure to place your name and other information as REMarks in the program. You can include a documentation file as well. The only thing that I ask is that you do not charge for the use of your program, as I am not charging for the use of this interpreter. Send me a note, and tell me where the code is and I will include it in the package. Thanks to all you have helped and are going to help! DESIGN CONSIDERATION When I was laying out the initial design of PBASIC, here are some of the topics I took into consideration: - Microsoft BASIC compatible. - Size of Interpreter (as small as possible). - Unique features of the Portfolio. - Using the Built-in editor for Program Editing. - Reasonable size BASIC programs. NEW FEATURES FOR VERSION 2.1 New Statements: DATA, READ, RESTORE New Functions : LOG TRON invoked from command line switch -T Adjusted the screen coordinates from 0,0 to 1,1 to match GWBASIC. While this will cause some incompatibilities with previous versions of PBASIC, it will make it more compatible with GWBASIC. INTERFACING WITH THE EDITOR Instead of trying to create an editor, PBASIC makes full use of the built in editor. If you run BASIC without any parameters, it will load the last file you used in the editor. To speed up the process, you might want to rename PBASIC.EXE to P.EXE, so you only need to type P<RETURN> at the prompt. You can also specify a file to execute on the command line. Whenever an error is detected, an error message is displayed, along with the line number. Press any key and PBASIC will invoke the built-in editor and point to the error position. This will only happen if the file you are executing is the same as the one you are editing. On other systems, you will be returned to the DOS prompt. ALTR.COM is a small TSR program that will, only from inside the editor, save the current file and invoke PBASIC. PBASIC.EXE should be rename P.EXE for the <ALT-R> command to work. ALTR takes up about 450 bytes. It can be removed by rebooting the machine. It can only be loaded into memory once. The <ALT-R> command will only work inside the editor. When the program is finished, PBASIC will wait for a keypress and then return you to the editor. RUNNING PBASIC There are two forms to execute PBASIC: PBASIC [-T] PBASIC filename.ext [-T] In the first form, the default file is the last one edited in the built-in editor on the Portfolio. The second form loads and executes the specified file. You must include the extension of the filename. If you have run the ALTR program before editing your code, you can execute PBASIC by pressing <ALT-R>. The command line switch -T will turn on the trace feature. This is the same as putting TRON at the beginning of you program. GENERAL Source code is standard ASCII format. Source code can be in upper or lower case. 200 floating point variables. Variable names can not exceed 8 characters in length. FOR/NEXT loops may be nested 10 deep. GOSUBs may be nested 10 deep. Line numbers are not required for each statement. Only 100 line numbers are allowed. They do not have to be in sequence. Line numbers can range from 0 to 99999. Multiple statements per line (:) is supported. DEVELOPING PROGRAMS WITH GWBASIC You can develop your programs on the PC with Microsoft BASIC or QuickBASIC. If using Microsoft BASIC, be sure to save the file in ASCII format [ SAVE "myfile",A ] so that it can be read by PBASIC. Do NOT attempt to use the Portfolio statements on the PC. Starting with version 2.0, all variables are floating point. The statement DEFINT A-Z will now generate a syntax error in PBASIC, since it has not been implemented yet. It is no longer treated as a remark. MATH EXPRESSIONS Single precision math. Parentheses supported. Standard operator evaluation. Hexidecmial and Octal constants are supported. - negation ^ exponent * multiply / divide % remainder (MOD) \ integer division + addition - subtraction NOTES ON CONVENTIONS USED An expression (exp) can contain variables, constants. When a dummy exp is indicated, it is suggested that you use a constant, i.e. POS(0). A variable name (varname) must be used when indicated. Unless otherwise noted, all parameters can be constants, variables or equations. BASIC STATEMENTS I have tried to keep the syntax and semantics for the statements as close to Microsoft BASIC as possible. The notes presented indicate exceptions. There are some statements included the are not from Microsoft. They will not run on GWBASIC. CLS Clears the screen. DATA list of numbers Allows for numbers to be stored inline. Data statements MUST have a line number. Numbers are separated by commas. Data statements may be located on any line of the program. 12 DATA 1,2,3,4,5,6 DEF SEG = exp Assigns a segment address for direct memory accessing via PEEK, POKE and CALL. DIM varname(size)[,varname(size)....] Creates a one dimensional array of single precision floating point variables. Arrays start at 0. Arrays are not initialized to a value. Arrays must be defined before they are used. Upper arrays bounds are not checked, arrays are not allowed to go below 0. END SYSTEM and END have the same effect. FOR varname = exp TO exp [STEP exp] You can not use an array element for varname. FORMFEED Send a formfeed to the printer. NOT GWBASIC. GOSUB line number GOTO line number IF exp THEN statement [ ELSE statement ] INPUT ["prompt" (,|;)] varname Read an integer from the keyboard. Only one variable is allowed per input. If a comma (,) separates the prompt string and the varname, no question mark (?) will be printed. If a semi- colon (;) is used, the question mark will appear. LOCATE row,col Move the cursor to row, col. LPRINT list of expressions Send output to printer. See PRINT. NEXT [varname] You can not use an array element for varname. ON exp GOTO list of line numbers ON exp GOSUB list of line numbers OUT port, exp Send value to the indicated port. POKE addr, exp Places value at SEG:addr. SEG is set via the DEF SEG statement. NOTE: Due to the design of the Portfolio, if you poke screen memory (DEF SEG=&HB000), the value may not appear. After you poke, you should use the REFRESH statement to update the screen. PRINT list of expressions List of Expressions can consist of strings, variables, constants or expressions, separated by the comma (,) or semi-colon (;) or a space ( ). PRINTER This is a toggle to start copying all PRINT statements to the printer. Issue it again and it will toggle off. Can be used instead of converting all PRINTs to LPRINTs. Information will still be displayed on the screen. This will not wrap the output lines like the screen will. NOT GWBASIC. PRTSC This invoke the PRINT SCREEN function to copy the screen out to the printer. If you are using a laser printer, you might want to use a FORMFEED after this to do a page eject. NOT GWBASIC. PSET (row, col) [, exp] Set the pixel at row, col to exp. The Portfolio, regardless of the screen mode, has a maximum 64x240 for row, col. Exp can evaluate to 0 or 1. RANDOMIZE Initialize the random number generator. READ list of variables Read the values of the variables from the DATA statements. Variables can be simple or array. REM Remark. The rest of the line is ignored. You can also use the quote (') mark as a REM statement. RESTORE [line number] Sets the internal data pointer to the specified line number. Line number specified must be a data statement. If no line number is given, the data pointer will point back to the first data location. RETURN SCREEN exp Set the screen mode. There is no testing for validity. Some of the values that work on the Portfolio are: 4 graphics 320x200 5 graphics 320x200 6 graphics 640x200 7 text 80x25 8 graphics 160x200 10 graphics 640x200 These are standard PC modes, but remember that the Portfolio Screen is only 240x64. If you use the screen function of the portfolio, it is highly recommend that you set the screen back to mode 7 before you exit. Many portfolio utilities only work in mode 7. At present, text will not be displayed properly on a graphics screen. STOP To allow for "breakpoints", STOP will terminate the program and display the line number. It will point the built-in editor to the last position executed if the editor file is the same as the file being executed. SWAP varname, varname SYSTEM END and SYSTEM have the same effect. TROFF Disable line tracing. TRON Enable line tracing. Will display the line number in brackets ([x]). Using this statement will slow down the program execution. Can be placed anywhere in program. WAIT Unlike the GWBASIC version, this only waits for a key press. It gives no prompt and returns no value. BASIC FUNCTIONS I have tried to keep the syntax and semantics for the functions as close to Microsoft BASIC as possible. The notes presented indicate exceptions. ABS(exp) Returns the absolute value of exp. ATN(exp) Returns the Arc Tangent of exp. COS(exp) Returns the Cosine of exp. CSRLIN Returns the current cursor line. EXP(exp) Returns e to the power of exp. FIX(exp) Returns the integer portion of exp. FRE(exp) Returns the free amount of memory. The parameter exp is a dummy expression. INP(port) Returns the byte value from port. INT(exp) Returns the integer portion of exp. LOG(exp) Returns the LOG of exp. LPOS(exp) Returns the current position of the line printer head. Exp is a dummy expression. PEEK(address) Returns the byte from memory location SEG:address. SEG is set via the DEF SEG instruction. POINT(row,col) Returns the value of the pixel at row,col. If this function does not appear to work, try running FIX0D, to fix the ROM pixel read function. POS(exp) Returns the current cursor column. Exp is a dummy expression. RAND(exp) This will return a number between 0 and exp-1. NOT GWBASIC. RND This will return an number between 0 and 1. SGN(exp) Returns the sign of exp. -1 exp < 0 0 exp = 0 1 exp > 0 SIN(exp) Returns the Sine of exp. SQR(exp) Returns the Square Root of exp. TAN(exp) Returns the Tangent of exp. TIMER Returns the number of seconds since midnight. PORTFOLIO ONLY STATEMENTS The statements in this section are specific to the Atari Portfolio and will not run on a regular PC. YOU CAN LOCK UP YOUR REGULAR PC IF YOU ATTEMPT TO USE THESE. ALARM This will beep the speaker, about once a second until the user presses a key. The program will then continue with the next statement. BEEP This will cause a single beep from the speaker. BOX row1, col1, row2, col2, type This will draw a box. Row1 and Col1 specify the upper left corner position of the box, while Row2 and Col2 specify the lower right corner. Type is 0 for single line box, and 1 for a double line box. Trying to draw a box larger than the screen (8x40) has unpredictable results. CLICK Make the key click sound. DIAL "number" This will dial the "number" through the speaker. Valid characters for tones are: 0 1 2 3 4 5 6 7 8 9 A B C D * #. The letters must be in uppercase. DISPLAY exp Set the Portfolio screen to Normal, Static or Tracked. 0=Static, 1=Normal, 2=Tracked. The mode is only effective while in PBASIC. Using this statement might clear the screen depending on the position of the cursor. ERRWIN row, col, "message" This will draw a box around the message and display it at the specified row, col. It will then beep and wait for a keypress. The text underneath the message is left untouched. Trying to place the message outside the screen (8x40) has unpredictable results. GETDISPLAY This function will return the current display mode. See DISPLAY for details. OFF This will turn the Portfolio off until the user presses a key. The program will continue execution with the next statement. PORT This function will return a 1 if running on a Portfolio, a 0 if not. Handy if you want to run program on both machines without locking up the PC. WARNING: There is no positive way to identify the Portfolio. This functions checks to see if the Interrupt 61h vector is pointing to 0000:0000. This is not normally used on the PC, but is on the Portfolio. If you are running a TSR that takes over this vector, PORT will return 1. REFRESH Copy video memory to the LCD controller. Needed for when you are doing direct write to screen memory. ROMVER This function will return the version number of the Portfolio rom's. SOUND code, duration This will activate the tone generator. Duration is the length of tone in 10 msec intervals. Tone codes are displayed below. These codes are taken from the Atari Portfolio Technical Reference Manual, copyrighted by the Atari Corporation. CODE NOTE Frequency (Hz) 48 D#5 622.3 49 E5 659.3 50 F5 698.5 51 F#5 740.0 52 G5 784.0 53 G#5 830.6 54 A5 880.0 55 A#5 932.3 56 B5 987.8 57 C6 1046.5 58 C#6 1108.7 41 D6 1174.7 59 D#6 1244.5 60 E6 1318.5 61 F6 1396.9 14 F#6 1480.0 62 G6 1568.0 44 G#6 1661.2 63 A6 1760.0 4 A#6 1864.7 5 B6 1975.5 37 C7 2093.0 47 C#7 2217.5 6 D7 2349.3 7 D#7 2489.0 Aside from these codes, other values will produce sounds as well. STATUS exp This will enable or disable the Status line. This is the line that you see when you use the <LOCK> key on the Portfolio. 0 for off, 1 for on. TICK exp Sets the Clock tick speed. 0 is Normal, 1 tick every 128 seconds. 1 is Fast, 1 tick every second. 1 uses much more power. VCSRLIN Returns the current virtual cursor line. VLOCATE row,col Move the virtual cursor to row, col. This location will be at position 1,1 on the physical screen. VMOVE dir, dis Move the screen in direction dir for dis number of lines. Works only in Static and Tracked modes. Same as using the ALT arrow keys. Values for dir are 1=Up,2=Down,3=Left,4=Right. VPOS(exp) Returns the current virtual cursor column. Exp is a dummy expression. UPGRADE HISTORY Version 2.1 August 4, 1990 New Statements: DATA, READ, RESTORE New Functions : LOG TRON invoked from command line switch -T Adjusted the screen coordinates from 0,0 to 1,1 to match GWBASIC. While this will cause some incompatibilities with previous versions of PBASIC, it will make it more compatible with GWBASIC. Added INP to the documentation. Added FRE to the documentation. Installed Binary search for command checking. Speed increase about 40%. One letter variable names are not checked in command table. Fixed the load routine to allow for no CR/LF at the end of the file. Fixed FIX function. Fixed scientific constants. Fixed power (^) function. Version 2.0 July 27, 1990 New Statements: LPRINT, PRINTER, FORMFEED, PRTSC, WAIT, OUT, DIM New Functions : LPOS, ATN, EXP, FIX, INT, COS, SIN, SQR, TAN, TIMER, \, INP, FRE New Portfolio Only : GETDISPLAY, DISPLAY, VLOCATE, VMOVE, VPOS, VCSRLIN, ROMVER, PORT 200 variables, 8 significant characters. <ALT-R> TSR to invoke BASIC from inside editor. Program size limited to available memory. All variables are now SINGLE PRECISION FLOATING POINT. One Dimensional Floating Point Arrays. Fixed FOR/NEXT looping with a negative step. Fixed the use of FUNCTIONS in PRINT statements. Fixed EOF error on Portfolio: Lockup if no END statement. Added extensive printer support. DEFINT will now cause a syntax error. RND was changed to make it MS compatible. SWAP was make array compatible. Fixed ... else "string" problem. Added NEXT to the documentation. Version 1.1 July 21, 1990 New Statements: DEF SEG, POKE New Functions : PEEK New Portfolio Only : REFRESH, TICK, CLICK, STATUS Automatically invoke Editor on Error. Fixed ALARM problem: keystroke was going into buffer. Fixed ON x GOTO/GOSUB problem: Offset line count by 1. Improved Error Detection. Allow REM in PRINT with preceding colon (:). Implement the quote (') as a substitute for REM. Fix PSET documentation to indicate ()'s. Screen mode changes, return to original on error. Allow for spaces as separator in PRINT. Version 1.0 July 14, 1990 Initial release. TECHNICAL NOTES PBASIC is about 2000 lines of code was written in Turbo C, version 2.0, compiled to an executable file just under 43k in size. PBASIC was then compressed with LZEXE, version 0.91, to further reduce the size to about 30k. PBASIC will run on a regular PC, providing you do not use any Portfolio specific statements. If you have the Portfolio Emulation software (I60, I61), you can use all the features. PBASIC was developed on a Packard Bell 286 PC with 640k of memory. It was tested on the Atari Portfolio, ROM version 1.052. BATCH CONSIDERATIONS If you are running PBASIC as a batch file, you can access the ERRORLEVEL code generated upon exit. 0 - Successful exit 1 - Program aborted 2 - STOP encountered FUTURE ENHANCEMENTS - Menus - CHAINing programs - PBASIC compiler - Increase compatibility with Microsoft BASIC THE FILES PBASIC.EXE The Interpreter. PBASIC.TXT This file. ALTR.COM TSR to execute PBASIC from editor. TEST.BAS A program to exercise the interpreter. Should not generate any errors. It will run on a PC or Portfolio. Take a look at it, it demos many of the features of the Portfolio Only routines. DAYS.BAS Sample programs. FIX0D.COM TSR fix for Portfolio graphics rom. FIX0D.TXT ABOUT THE AUTHOR Mr. BJ Gleason is an Instructor at The American University in the Computer Science and Information Systems Department. He has been programming for over a decade now. COMMENTS, BUGS AND IDEAS What features do you really need in PBASIC to make it more useful on the Portfolio? If you would like to see some new features, contact me and I will try to accommodate you and release a new version. Thanks to all those on GEnie and Compuserve for their bug reports, suggestions and words of encouragement. Without their feedback, version 2.1 would have never seen the light of day. Keep those cards and letters coming! ADDRESS If you have an comments, suggestions or bug reports, you can write to the author at: BJ Gleason The American University CSIS (Thin Air Labs) 4400 Massachusetts Avenue, N.W. Washington, DC 20016 Compuserve : 73337,2011 Genie : BJGLEASON This program and documentation is being placed into the public domain by the author. It can be copied and distributed freely. It can not be sold or used for commercial purposes without permission. PBASIC version 2.1, Copyright 1990 by BJ Gleason. Portfolio, Atari, Microsoft, GWBASIC are trademarks of their respective companies. ə