Intel 9800758-02 manual On ... Gosub, On ... Goto, Open

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Commands and Statements

BASIC-SO

ON ... GOSUB

The ON ... GOSUB statement transfers program control to one or one of a set of subroutines.The line numbers of the first lines of these subroutines follow sequen- tially, separated by commas. If the expression evaluates to 3, control transfers to the third line number following GOSUB.

ON expression GOSUB line number [,Iine number] ...

10 INPUT A

20 ON A GOSUB 200,300

ON ... GOTO

The ON ... GOTO statement transfers program control to one or one of a set of line numbers. The expression X is evaluated and control is transferred to the "nth" line number following the line containing the ON ...GOTO instruction. If the expression evaluates to 3, control transfers to the third line number following GOSUB.

ON expression GOTO line number [,Iine number] ...

10 INPUT A

20 ON A GOTO 500,510,520

OPEN

The OPEN statement makes an ISIS-II file available to BASIC. It also associates a file number from 1 to 6 with the file. File type can be I, 0, or R. Random 110 files are specified by an R, sequential input files are specified by an I, and sequential output files are specified by an 0, as shown in the syn- tactic format below. The file number is an integer expression greater than 0 and less than or equal to 6, is preceded by a "#" sign, and is used to reference the file in 110 transactions.

Only six files may be open at one time. Note that SAVE, LOAD, DSKF; DIR and MERGE all require a file, so a maximum of five files may be open before they are executed.

BASIC-SO buffers files, so if :CI: is opened for input, BASIC-SO will wait for the first line of console input.

OPEN type, [I] file number, filename

where type is a string expression equal to "0", "I" or "R". In the example below, the file SYSLIB is opened as a random I/O file, with number 4.

OPEN "R" ,#4, "SYSLlB"

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Contents BASIC-SO Reference Manual A108/0979/7500 FL Preface Page Contents Illustrations Chapter Introduction to BASIC-80 Invoking BASIC-80Basic filename MEMTOPaddress ExamplesIntroduction to BASIC-80 FilenameChanging File Attributes Listing the Directory of a DiskRenaming a File Deleting a FileYou can now run, list, or edit the program Save LP ,ACommands StatementsBASIC-80 Commands Contd BASIC-80 StatementsBASIC-80 Statements Contd BASIC-80 FunctionsBASIC-80 Functions Contd Representing Data FunctionsDecimal Integer Constants ConstantsInteger Constants Hexadecimal Integer ConstantsOctal Integer Constants Single-Precision Floating-Point ConstantsDouble-Precision Floating-Point Constants This is a string constant String ConstantsString Variables $ = Enter next data stringL4! = Csng l4 YI,1String Arrays Arithmetic Operators BASIC-SO Operators in Order of Precedence ContdNumeric Expressions Logical OperatorsString Operator String ExpressionsEntering and Editing Programs 30 A=8*52 30 A=8*37 30 A=8*5230 A=8 30 A--=8xx*522537 Control-R a = 8*37Integer D SubcommandCommand 3D press 3, then D results If AB thenIf AB then 120 Else Null SET Syntax of the X subcommand is At this point, the other editing subcommands may be usedMove the cursor to PRINT. Enter 2C RE L Print Undefined SET The E subcommand is enteredInteger C character character Print Undefined SET. Enter a LBASIC-80 Error Messages Syntax Error MessagesOverflow, Underflow, and Divide-by-Zero Error Trapping Trace Facility Restarting Program Execution Error SimulationError Handling If line 40 is replaced withOpening a Sequential File Open 1,#1,F1DATESReading from a Sequential File Refer to for further details of Print UsingWriting to a Sequential File If executed four times, it would read all eight valuesClosing a Sequential File Value of R$ would beBuffers Defining a Random 1/0 Field-FIELDField #3, 20 AS N$ Disk File Input/Output Field #3, 20 AS N$, 9 AS SS$Any of the parameters can be variables Opening and Closing a Random Disk FileReading from a Random 1/0 File To read the next recordSingle-precision value Writing to a Random 1/0 FileInteger Double-precision valueMKI$ Auto first lineJ, increment Attrib Fdrive numberfilename, W1Attrib Fdrive numberfilename, WO Clear expression,addressCommands and Statements CloseDEF FNX Rules for function name are the same as for variable nameDefsng Defdbl Defstr Defint DIM DeleteEdit ErrorDIR ENDField Error expressionExit FOR-NEXT-STEPFor variable=expression to expression Step expression GETGosub GET I file number ,record numberIF-THEN-ELSE InputGoto Line Input KillLET ListLSET, Rset LoadMerge NEWNext 9 16On ... Gosub On ... GotoOpen Option Base OUTPoke Print Using PrintString Fields Numeric fields If X$=SEVEN and Y$=EIGHT, the results of line 40 would bePrun PUTRandomize ReadREM Resume ReturnLine number RUN filename SaveRUN line numberlstring expression ,F 60 ENDTRON, Troff ? 5,8,2Wait WidthABS ATNCHR$ CintFunctions 10 A# = 1.00/3.00 CsngCVI CVS AO/o =Dskf EOFFIX Ok·Hexs INPInputs INT InstrLEFT$ LOF LENLOC LOGMID$ MKI$ MKS$ MKD$OCT$ POS integer RightsPeek expression RIGHT$ string,integerSpaces SGNSIN 10 a =1If A$ = 2 then Print Correct Else Goto SPCSPC integer SQRexpressionSTR$ expression TAB expressionTAN expression Here is an example of how the USRn statement is used 60 AO/o =Appendix a BASIC-SO Error Codes Table A-I. BASIC-80 Error CodesTable A-I. BASIC-SO Error Codes Contd Appendix B BASIC-SO Reserved Words Page To tab across the line To halt program execution and return to commandLevel To resume program execution after it is stopped byPage Table D-l. Ascii Code List Appendix D Ascii CodesTable D-2. Ascii Code Definition BELAppendixe Calling Subroutines Figure B-1. Internal Representation of Numbers and Strings Some Real Examples RESULT=USR%1VARPTRA, VARPTRB, VARPTRC» PRINTA+B+C= ResultFigure E-2 /8085 Assembly Language Program Figure E-3. PL/M-80 Program Appendix F RMX/SO BASIC-SO Initializing the Predefined RMX/SO BASIC-SO Configuration ISIS-II BASIC-SOTable F-l. Sample Configuration Jumper Wiring OOOOH-OFFFHBASIC-80 Object Files Generating Boot-Loaded and PROM-Based VersionsBASIC-80 Source Files BASIC-80 Executable FilesGenerating a Boot-Loaded RMX/80 BASIC-80 Setting baud rates, refer to the RMX/SO Users Guide That are not boot loadedThis option is used to allocate memory. It is 1 if the boot This option enables your user-written I/O drivers if youISBC 80/20-4 Generating a PROM-Based RMX/80 BASIC-80 Prom F1 RMX820.L1BSTART, & FOBASCM.OBJ,& FORMXBAS.LlB F1 DFSDIR. L1BDIRECTORY ,RENAM E,& F1 MTI810.L1B Configuration Requirements Configuring DFS on an iSBC 80/10Adding BASIC-SO to an Existing RMX/SO Configuration ISBC SO/10 System ClockPublic Variables Adding User-Written I/O Drivers to RMX/SO BASIC-SO Open 0,#1, L1LlSTFigure F-S. Sample User-Written 1/0 Driver Routine Altering BASIC-80 Workspace Burning a BASIC-80 Program Into PromBaprom F1HEATER.BAS Page Index Ase BASIC-80 RIGHT$,7-1O Request for Readerscomments 111111