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.hm 1 .he PART 5: Programming Reference Information .paè.he UCPM Manual, Reference, Page # A. CP/M BDOS AND BIOS REFERENCE 1. BDOS Calls Function and Number Input Parameters Output Parameters System Reset 0 None None Read Console 1 None ASCII Char in A Write Console 2 ASCII Char in E None Read Reader 3 None ASCII Char in A Write Punch 4 ASCII Char in E None Write List 5 ASCII Char in E None Direct Con I/O 6 ASCII Char in E I/O Status in A if E=0FFH Get I/O Status 7 None I/O Status in A Put I/O Status 8 I/O Status in E None Print Buffer 9 Address of string None terminated by $ in DE Read Buffer 10 Address of Read Read Buffer is filled Buffer in DE Console Ready 11 None LSB of A is 1 if char ready *All function numbers are passed in Reg C. 2« BIOS Calls Function and Number Input Parameters Output Parameters Return Version # 12 None Version Info in HL H=0 CP/M, H=1 MP/M L=00 CP/M 1.x, 2x 2.x Init BDOS 13 None None Log-In Disk 14 Value in Reg E None A=0, B=1, C=2, D=3 Open File 15 Address of FCB Byte address of FCB in DE if found or 0FFH if not Close File 16 Address of FCB Byte address of FCB in DE if found or 0FFH if not Search for File 17 Address of FCB Byte address of FCB (0-3) in DE if found or 0FFH if not Search for Next 18 Address of FCB Byte address of next FCB in DE if found or 0FFH if not Delete File 19 Address of FCB Byte address of FCB (0-3) in DE if found or 0FFH if not Read Next Record 20 Address of FCB 0=successful read in DE 1=read past EOF 2=reading random data Write Next Rec 21 Address of FCB 0=successful write in DE 1=error in extending 2=end of disk data 255=no more dir space Make File 22 Address of FCB Byte address of FCB orè in DE 255 if no more dir space Rename FCB 23 Address of FCB Byte Address of Dir entry in DE or 255 if no match Return Log Code 24 None Login vector in HL Read Drive No 25 None Number of logged-in drive (A=0, B=1, C=2, D=3) Set DMA Address 26 Address of 128 None byte buffer in DE Get Alloc Vect 27 None Allocation Vect Addr in HL Write Prot Disk 28 None None Get R/O Vect 29 None HL=R/O Vect Val Set File Attrib 30 Ptr to FCB in DE Dir code in A Get Disk Parms 31 None HL=DPB Address Set/Get Usr Code 32 E=0FFH (get)/Code A=Current code (get)/no (set) value (set) Read Random 33 DE=FCB addr A=return code 1=reading unwritten data 2=(not used) 3=can't close curr ext 4=seek to unwritten ext 5=(not used) 6=seek past end of disk Write Random 34 DE=FCB addr A=return code 1=reading unwritten data 2=(not used) 3=can't close curr ext 4=seek to unwritten ext 5=dir overflow 6=seek past end of disk Compute File Siz 35 DE=FCB addr Random Rec Field set to file size Set Random Rec 36 DE=FCB addr Random Rec Field set *All function numbers are passed in Reg C .paèB. Reference for Standard CP/M Assembly-Language Tools 1. ASM The ASM Command loads and executes the CP/M 8080 assembler. It is of the form -- ASM filename.xyz where filename ... is the name of the file 'filename.ASM' to assemble x ... designates the disk name which contains the source y ... designates the disk name to contain the hex file (y=Z suppresses generation of the hex file) z ... designates the disk name to contain the print file (y=X lists on CON:, y=Z suppresses listing) 2. LOAD áááááThσá LOA─á CommanΣ read≤ thσ filσ specified¼á whicΦ i≤á assumeΣá t∩ ì ááááácontaiεá Inte∞ he° forma⌠ machinσ codσ anΣ produce≤ ß memor∙á imagσ ì áááááfilσá whicΦá caε bσ subsequentl∙ executeΣ (convert≤á .HE╪á t∩á .CO═ ì áááááfiles)« I⌠ i≤ oµ thσ forφ -- LOAD filename áááááwherσ filenamσ i≤ thσ namσ oµ thσ filσ 'filename.HEX'. 3. DDT áááááThσá DD╘ Prograφ allow≤ dynamiπ interactivσ testinτ anΣ debugginτ ì áááááoµ program≤ generateΣ iε thσ CP/═ environment« I⌠ i≤ invokeΣ b∙ -- DDT DDT filename.HEX DDT filename.COM where 'filename' is the name of the program to be loaded or tested. DDT responds to the normal CP/M input line editing characters. DDT responds to the following commands -- As Perform inline assembly starting at the specified address s. D Display memory from the current address for 16 display lines. Ds Display memory from address s for 16 display lines. Ds,f Display memory from address s to address f. Fs,f,c Fill memory from start address s to final address f with byte c.è G Start execution at the current value of the PC. Gs Start execution at the specified address s. Gs,b Start execution at the specified address s and set a breakpoint at the address b. Gs,b,c Same as above with breakpoints at b and c. G,b Start execution at the current value of the PC with breakpoint b. G,b,c Same as above with breakpoints at b and c. If Insert a file name f into the default FCB. L List 12 lines of disassembled code from the current address. Ls List 12 lines from the specified address s. Ls,f List lines of disassembled code from s to f. Ms,f,d Move the block from address s to f to destination at address d. R Read file in FCB into memory at 100H. Rb Read file in FCB into memory with offset b from 100H. Ss Set (examine and alter) memory starting at address s. T Trace the next instruction. Tn Trace the next n instructions. U Untrace -- like Trace, but intermediate steps are not displayed. X Examine all registers and flags. Xr Examine specified registers or flag, where r may be -- C Carry flag Z Zero flag M Minus (sign) flag I Interdigit Carry flag A Accumulator B BC Reg pair D DE Reg pair H HL Reg pair S Stack pointer P PC 4. MAC áááááMA├á i≤ thσ CP/═ StandarΣ Macr∩ Assembler╗á i⌠ i≤ upward-compatablσ ì áááááwitΦá ASM¼á thσ CP/═ StandarΣ Assembler«á Thσ facilitie≤ oµá MA├ ì áááááincludσá assembl∙á oµá Inte∞á 808░á microcompute≥á mnemonics¼ ì áááááalonτá witΦ assembly-timσ expressions¼á conditiona∞á assembly¼ ì ááááápagσ formattinτ features¼ anΣ ß macr∩ processo≥ whicΦ i≤ compaì ááááátablσá witΦá thσ standarΣ Inte∞ definitioε (MA├á implement≤á thσ ì ááááámid-197╖ revisioε oµ Intel'≤ definition). .cp 6è MAC is invoked by the following command -- MAC d:filename $parms áááááOnl∙ 'filenameº i≤ required¼á anΣ i⌠ represent≤ ß filσ nameΣ 'fileì áááááname.ASM'«á MA├á ma∙ theε generatσ u≡ t∩ │ othe≥ file≤á -- fileì áááááname.HE╪ (thσ Inte∞ He° Forma⌠ File)¼á filename.PR╬ (thσ Prin⌠ o≥ ì áááááListinτ file)¼á anΣ filename.SY═ (ß filσ containinτ ß sorteΣ lis⌠ ì áááááoµ thσ symbol≤ useΣ iε thσ program). áááááMACR╧ Librar∙ file≤ ma∙ bσ referenceΣ b∙ thσ program╗á thesσ file≤ ì áááááarσ nameΣ 'filename.LIB'. ááááá$parm≤á represent≤ thσ optiona∞ assembl∙ contro∞ parameter≤á whicΦ ì áááááarσ discusseΣ iε thσ nex⌠ section. áááááMA├á ma∙á bσá executeΣ b∙ employinτá thσá SUBMI╘á filσá MAC.SUB« ì áááááMAC.SU┬ assemble≤ thσ specifieΣ MA├ .AS═ file¼á convert≤ i⌠ int∩ ì áááááßá .CO═á filσá viß LOAD¼á anΣ erase≤ thσ .HE╪á file«á MAC.SU┬á i≤ ì áááááinvokeΣ b∙ -- SUBMIT MAC filename áááááwherσ 'filenameº i≤ thσ namσ oµ thσ MA├ filσ 'filename.ASM'. áááááThσ contro∞ paramete≥ lis⌠ i≤ precedeΣ b∙ ß $¼ anΣ ma∙ contaiε an∙ ì áááááoµ thσ followinτ iε an∙ orde≥ -- A - controls the source disk for the .ASM file H - controls the destination of the .HEX machine code file L - controls the source disk for the .LIB files M - controls MACRO listing in the .PRN file P - controls the destination of the .PRN listing file Q - controls the listing of LOCAL symbols S - controls the generation and destination of the .SYM file 1 - controls pass 1 listing áááááIε thσ casσ oµ thσ A¼á H¼á L¼á P¼á anΣ ╙ parameters¼á the∙ ma∙á bσ ì áááááfolloweΣ b∙ thσ drivσ namσ froφ whicΦ t∩ obtaiε o≥ t∩ whicΦ t∩ senΣ ì ááááádata¼ wherσ -- A,B,C,D -- designates that particular drive P -- designates the LST: device X -- designates the user console (CON:) Z -- designates a null file (no output) For example, $PB AA HB SX ááááásend≤á thσ .PR╬ filσ t∩ drivσ B:¼á get≤ thσ .AS═ filσ froφá drivσ ì áááááA:¼á send≤á thσ .HE╪ filσ t∩ drivσ B:¼á anΣ send≤ thσ .SY═ filσ t∩ ì áááááCON:. áááááThσ parameter≤ L¼ S¼ M¼ Q¼ anΣ ▒ ma∙ bσ precedeΣ b∙ eithe≥ ½ o≥ - ì ááááát∩ enablσ o≥ disablσ thei≥ respectivσ function≤ -- +L - list the input lines read from the MACRO library -L - suppress listing of the MACRO library (default) è +S - append the .SYM output to the end of the .PRN file (default) -S - suppress the generation of the sorted symbol table +M - list all MACRO lines as they are processed (default) -M - suppress all MACRO lines as they are processed *M - list only HEX code generated by macro expansions in listing +Q - list all LOCAL symbols in the symbol list -Q - suppress all LOCAL symbols in the symbol list (default) +1 - produce a listing file on the first pass (for MACRO debugging) -1 - suppress listing on pass 1 (default) áááááThσá programme≥á caεá interspersσá control≤á throughou⌠áá thσ ì áááááassembl∙ languagσ sourcσ o≥ librar∙ files«á IntersperseΣ control≤ ì áááááarσá denoteΣá b∙ ß "$ó iε thσ firs⌠ columε oµ thσá inpu⌠á linσ ì áááááfolloweΣ immediatel∙ b∙ ß parameter. The following Pseudo-Ops are supported -- DB defines data bytes or strings of data DS reserves storage areas DW defines words of storage ELSE alternate to IF END terminates the physical program ENDIF marks the end of conditional assembly ENDM marks the end of a MACRO EQU performs a numeric "equate" EXITM abort expansion of the current MACRO level IF begins conditional assembly IRP INLINE MACRO with string substitution IRPC INLINE MACRO with character substitution LOCAL define LOCAL variables unique to each MACRO repetition MACLIB specify MACRO Library to load MACRO defines beginning of a MACRO ORG sets the program or data origin PAGE defines the listing page size for output REPT defines the beginning of a INLINE MACRO SET performs a numeric "set" or assignment TITLE enables page titles and options ááááá┬á - Balancσ error║á MACR╧ doesn'⌠ terminatσ properl∙ o≥ condiì ááááátiona∞ assembly is ill-formed ááááá├á - Commßá error║áá expressioεá wa≤á encountereΣá bu⌠á no⌠ ì ááááádelimiteΣ properly from the next item by a comma ááááá─á - Datσá error║á elemen⌠ iε ß datß statemen⌠ (DB,DW⌐á canno⌠á bσ ì áááááplaceΣ iε thσ specifieΣ datß area E - Expression error: expression is ill-formed and cannot be computed I - Invalid character: a non-graphic character has been found L - Label error: label cannot appear in this context M - MACRO overflow error: internal MACRO expansion table overflow N - Not implemented error: unimplemented feature used ááááá╧ - Overflo≈ error║á expressioε i≤ to∩ complicateΣ o≥ thσ numbe≥ ì áááááoµ LOCA╠ label≤ ha≤ exceedeΣ 9999 ááááá╨á - Phasσá error║á label≤ doe≤ no⌠ havσ samσ valuσá oεá botΦ ìèááááápasse≤ (multiplσ label) ááááá╥á - Registe≥ error║á valuσ specifieΣ fo≥ ß registe≥ i≤ no⌠á comì ááááápatablσ witΦ o≡ code S - Statement/Syntax error: statement is ill-formed V - Value error: operand is improperly formed or out of range Console Error Messages: NO SOURCE FILE PRESENT - .ASM file not found NO DIRECTORY SPACE - Directory is full áááááSOURC┼á FIL┼á NAM┼á ERRO╥ - Thσ forφ oµ thσ sourcσá filσá namσá i≤ ì áááááinvalid╗á notσ tha⌠ MA├ i≤ invokeΣ b∙ 'MA├ filename'¼ anΣ thσ .AS═ ì áááááfilσ typσ i≤ NO╘ specified. SOURCE FILE READ ERROR - Error in reading source file OUTPUT FILE WRITE ERROR - Error in writing output file CANNOT CLOSE FILE - An output file cannot be closed. UNBALANCED MACRO LIBRARY - No ENDM encountered for a MACRO definition áááááINVALI─á PARAMETE╥ - InvaliΣ assembl∙ paramete≥ wa≤ founΣá iεá thσ ì áááááinpu⌠ line. 5. LINK The format for the invocation of Linker is LINK <filename1.ext/s,filename2.ext/s,....> where filename stands for Disk drive letter followed by a colon followed by the absolute file name ext is used if the module extension is different than .rel /s stands for switch options. EXAMPLE of a link LINK MAIN,FORLIB/S,MAIN/N/G/E The first MAIN is the name of the module from the fortran compiler The FORLIB/S is the library of standard fortran routines that will be selected The MAIN/N/G/E means to name the .COM file MAIN and to save it on current disk then execute MAIN automatically. SWITCH OPTIONS Each switch option is preceded by a / E .... Exit to operating system G .... Go start execution Start execution of the program as soon as the current command line has been interpreted. è M .... Map all symbols List both all the defined globals and their values and all undefined globals followed by an asterisk. R .... Reset the linker Puts the linker back to its initial state. the /R is used to restart LINK if the wrong file was loaded by mistake. S .... Search file Search the disk file having the filename immediately preceding the /S in the command string, to satisfy any undefined globals. This is convenient for having the linker search a library file of musch-used routines. U .... List all undefined globals List all undefined globals as soon as the current command line has been interpreted and executed. Link defaults to this switch; therefore it is generally not needed. ERROR MESSAGES: No start address a /G is issued but no main program module has been loaded. Loading error The file given is not a properly formatted link object file. Fatal Table Collision There is not enough memory Command error Unrecognizable link command File not found Specified file not on specified disk mult def global More than one definition of the global name (possibly wrong modules combined) 6. SID Syntax: SID {pgm-filespec} {,sym-filespec} Explanation: áááááThσá SI─ symboliπ debugge≥ allow≤ yo⌡ t∩ monito≥ anΣá tes⌠ ì áááááprogram≤á developeΣ fo≥ thσ 808░ microprocessor«á SI─ support≤ ì áááááreal-timσ breakpoints¼á full∙ monitoreΣ execution¼á symboliπ ì ááááádisassembly¼á assembly¼á anΣ memor∙ displa∙ anΣ fil∞ functions« ì áááááSI─á caε dynamicall∙ loaΣ SI─ utilit∙ program≤ t∩á providσ ì ááááátracebacδ anΣ histograφ facilities. .cp 6è Commands: Command Meaning As (Assemble) Enter assembly language statements s is the start address Cs{b{,d}} (Call) Call to memory location from SID s is the called address b is the value of the BC register pair d is the value of the DE register pair D{W}{s}{,f} (Display) Display memory in hex and ASCII W is a 16-bit word format s is the start address f is the finish address Epgm-filespec (Load) Load program and symbol table {,sym-filespec} for execution E*sym-filespec (Load) Load a symbol table file Fs,f,d (Fill) Fill memory with constant value s is the start address f is the finish address d is an eight-bit data item G{p}{,a{,b}} (Go) Begin Execution p is a start address a is a temporary breakpoint H (Hex) Displays all symbols with addresses in Hex H.a Displays hex, decimal, and ASCII values of a where a is a symbolic expression Ha,b Computes hex sum and difference of a and b where a and b are symbolic expressions Icommand tail (Input) Input CCP command line L{s}{,f} (List) List 8080 mnemonic instructions s is the start address f is the finish address Ms,h,d (Move) Move Memory Block s is the start address h is the high address of the block d is the destination start address è P{p{,c}} (Pass) Pass point set, reset, and display p is a permanent breakpoint address c is initial value of pass counter Rfilespec{,d} (Read) Read Code/Symbols d is an offset to each address S{W}s (Set) Set Memory Values s is address where value is sent W is 16 bit word T{n{,c}} (Trace) Trace Program Execution n is the number of program steps c is the utility entry address. T{W}{n{,c}} (Trace) Trace Without Call W instructs SID not to trace subroutines n is the number of program steps c is the utility entry address U{W}{n{,c}} (Untrace) Monitor Execution without Trace n is the number of program steps c is the utility entry address W instructs SID not to trace subroutines V (Value) Display the value of the next available location in memory (NEXT), the next location after the largest file read in (MSZE), the current value of the Program counter (PC), and the address of the end of available memory (END) Wfilespec,s,f (Write) Write the contents of a contiguous block of memory to filespec. f is finish address X{f}{r} (Examine) Examine/alter CPU state. f is flag bit C,Z,M,E or I. r is register A,B,D,H,S or P. .paèC. Microsoft BASIC Reference 1. General Statements Command Syntax Function AUTO AUTO [line][,inc] Generate line numbers CLEAR CLEAR [,[exp1][,exp2]] Clear program variables; Exp1 sets end of memory and Exp2 sets amount of stack space CONT CONT Continue program execution DELETE DELETE [[start][-[end]]] Delete program lines EDIT EDIT line Edit a program line FILES FILES [filename] Directory LIST LIST [line[-[line]]] List program line(s) LLIST LLIST [line[-[line]]] List program line(s) on printer LOAD LOAD filename[,R] Load program; ,R means RUN MERGE MERGE filename Merge prog on disk with that in mem NAME NAME old AS new Change the name of a disk file NEW NEW Delete current prog and vars NULL NULL exp Set num of <NULL>s after each line RENUM RENUM [[new][,[old][,inc]]] Renumber program lines RESET RESET Init CP/M; use after disk change RUN RUN [line number] Run a prog (from a particular line) RUN filename[,R] Run a prog on disk SAVE SAVE filename[,A or ,P] Save prog onto disk; ,A saves prog in ASCII and ,P protects file SYSTEM SYSTEM Return to CP/M TROFF TROFF Turn trace off TRON TRON Turn trace on WIDTH WIDTH [LPRINT] exp Set term or printer carriage width; 2. Program Control Statements CALL CALL variable [(arg list)] Call assembly or FORTRAN routine CHAIN CHAIN [MERGE] filename [,[line exp][,ALL][,DELETE range]] Call a program and pass variables to it; MERGE with ASCII files allows overlays; start at line exp if given; ALL means all variables will be passed (otherwise COMMON only); DELETE allows deletion of an overlay before CHAIN is executed COMMON COMMON list of vars Pass vars to a CHAINed prog DEF DEF FNx[(arg list)]=exp Arith or String Function DEF USRn=address Define adr for nth assembly routine DEFINT range(s) of letters Define default var type INTeger DEFSNG " " " " " " " Single DEFDBL " " " " " " " Double DEFSTR " " " " " " " String DIM DIM list of subscripted vars Allocate arrays END END Stop prog and close files ERASE ERASE var [,var ... ] Release space and var names ERROR ERROR code Generate error code/message FOR FOR var=exp TO exp [STEP exp] FOR loop GOSUB GOSUB line number Call BASIC subroutineèGOTO GOTO line number Branch to specified line IF/GOTO IF exp GOTO line [ELSE stmt ... ] IF exp <> 0 then GOTO IF/THEN IF exp THEN stmt[:stmt] [ELSE stmt ... ] IF exp <> 0 then ... else ... LET [LET] var=exp Assignment MID$ MID$(string,n[,m])=string2 Replace a portion of string with string2; start at pos n for m chars NEXT NEXT var[,var ... ] End FOR ON ERROR ON ERROR GOTO line Error trap subroutine GOTO ON/GOSUB ON exp GOSUB line[,line] Computed GOSUB ON/GOTO ON exp GOTO line[,line] Computed GOTO OPTION OPTION BASE n Min val for subscripts (n=0,1) BASE OUT OUT port,byte Output byte to port POKE POKE address,byte Memory put RANDOMIZE RANDOMIZE [exp] Reseed random number generator REM REM any text Remark -- comment RESTORE RESTORE [line] Reset DATA pointer RESUME RESUME or RESUME 0 Return from ON ERROR GOTO RESUME NEXT Return to stmt after error line RESUME line Return to specified line RETURN RETURN Return from subroutine STOP STOP Stop prog and print BREAK msg WAIT WAIT prot,mask[,select] Pause until input port [XOR select] AND mask <> 0 WHILE/ WHILE exp stmts ... WEND Execute stmts as long as exp is T WEND 3. Input - Output Statements Statement Syntax/Function CLOSE CLOSE [[#]f[,[#]f ... ]] Close disk files; if no arg, close all DATA DATA constant list List data for READ statement FIELD FIELD [#]f,n AS string var [,n AS string var ...] Define fields in random file buffer GET GET [#]f[,record number] Read a record from a random disk file INPUT INPUT [;] [prompt string;] var [,var ...] INPUT [;] [prompt string,] var [,var ...] Read data from the terminal; leading semicolon suppresses echo of <CR>/<LF> and semicolon after prompt string causes question mark after prompt while comma after prompt suppresses question mark KILL KILL filename Delete a disk file LINE LINE INPUT [;] [prompt string;] string var INPUT Read an entire line from terminal; leading semicolon suppresses echo of <CR>/<LF> LINE INPUT #f,string var Read an entire line from a disk fileèLSET LSET field var=string exp Store data in random file buffer left-justified or left-justify a non-disk string in a given field OPEN OPEN mode,[#] f,filename Open a disk file; mode must be one of -- I = sequential input file O = sequential output file R = random input/output file PRINT PRINT [USING format string;] exp [,exp ...] Print data at the terminal using the format specified PRINT #f, [USING format string;] exp [,exp ...] Write data to a disk file LPRINT [USING format string;] var [,var ...] Write data to a line printer PUT PUT [#] f [,record number] Write data from a random buffer to a data file READ READ var [,var ...] Read data from a DATA statement into the specified vars RSET RSET field var = string exp Store data in a random file buffer right justified or right justify a non-disk string in a given field WRITE WRITE [list of exps] Output data to the terminal WRITE #f, list of exps Output data to a sequential file or a random field buffer 4. Mathematica∞ Functions Function Action ABS(exp) Absolute value of expression ATN(exp) Arctangent of expression (in radians) CDBL(exp) Convert the expression to a double precision number CINT(exp) Convert the expression to an integer COS(exp) Cosine of the expression (in radians) CSNG(exp) Convert the expression to a single precision number EXP(exp) Raises the constant E to the power of the expression FIX(exp) Returns truncated integer of expression FRE(exp) Gives memory free space not used by MBASIC INT(exp) Evaluates the expression for the largest integer LOG(exp) Gives the natural log of the expression RND[(exp)] Generates a random number exp <0 seeds new sequence exp =0 returns previous number exp >0 or omitted returns new random number SGN(exp) 1 if exp >0 0 if exp =0 -1 if exp <0 SIN(exp) Sine of the expression (in radians) SQR(exp) Square root of expression TAN(exp) Tangent of the expression (in radians) .cp 6è5« Strinτ Functions ASC(str) Returns ASCII value of first char in string CHR$(exp) Returns a 1-char string whose char has ASCII code of exp FRE(str) Returns remaining memory free space HEX$(exp) Converts a number to a hexadecimal string INPUT$(length [,[#]f]) Returns a string of length chars read from console or from a disk file; characters are not echoed INSTR([exp,]str1,str2) Returns the first position of the first occurrence of str2 in str1 starting at position exp LEFT$(str,len) Returns leftmost length chars of the string expression LEN(str) Returns the length of a string MID$(string,start[,length]) Returns chars from the middle of the string starting at the position specified to the end of the string or for length characters OCT$(exp) Converts an expression to an Octal string RIGHT$(str,len) Returns rightmost length chars of the string expression SPACE$(exp) Returns a string of exp spaces STR$(exp) Converts a numeric expression to a string STRING$(length,str) Returns a string length long containing the first char of the str STRING$(length,exp) Returns a string length long containing chars with numeric value exp VAL(str) Converts the string representation of a number to its numeric value 6« Othe≥ Functions Function Action CVI(str) Converts a 2-char string to an integer CVS(str) Converts a 4-char string to a single precision number CVD(str) Converts an 8-char string to a double precision number EOF(f) Returns TRUE (-1) if file is positioned at its end ERL Error Line Number ERR Error Code Number INP(port) Inputs a byte from an input port LOC(f) Returns next record number to read or write (random file) or number of sectors read or written (sequential file) LPOS(n) Returns carriage position of line printer (n is dummy) MKI$(value) Converts an integer to a 2-char string MKS$(value) Converts a single precision values to a 4-char string MKD$(value) Converts a double precision value to an 8-char string PEEK(exp) Reads a byte from memory location specified by exp POS(n) Returns carriage position of terminal (n is dummy) SPC(exp) Used in PRINT statements to print spaces TAB(exp) Used in PRINT statements to tab to specified positionèUSR[n](arg) Calls the user's machine language subroutine with the arg VARPTR(var) Returns address of var in memory or zero if var has not been assigned a value VARPTR(#f) Returns the address of the disk I/O buffer assigned to file number .paè