HP 3000 Manuals HP 3000 Manuals
FORTRAN 77/XL Enhancements by Erryl Johnson--Data & Languages Division/CLL This new version of FORTRAN 77/XL (A.02.00) has been enhanced by the addition of HP 3000 extensions, and other extensions that provide increased compatibility with FORTRAN 66/V, HP 1000 FORTRAN 77 and the DEC/VMS implementation of FORTRAN 77. HP 3000 EXTENSIONS FORTRAN 66/V I/O - The $FTN3000_66 compiler directive has been enhanced by the addition of the IO option. This option creates compatibility with FORTRAN 66/V files. This compatibility is achieved by reading and writing CHARACTER items in unformatted files in two-byte blocks and by performing multiple physical I/O operations for I/O lists that request them. FORTRAN 66/V LOGICALS - The $FTN3000_66 compiler directive has been enhanced to include the LOGICALS option, which causes logical data to have the same internal representation as FORTRAN 66/V. PROGRAM UNIT PER OBJECT MODULE - The $RLFILE directive causes each program unit (identified by a PROGRAM, SUBROUTINE, FUNCTION or BLOCK DATA statement) to be compiled into its own object module and placed in a file of type NMRL. In subsequent compilations into the same RL file, program units will replace corresponding object modules of the same name. This capability allows you to add and delete entries on the program unit level (versus module level) using Link Editor/XL. The $RLINIT directive causes the compiler to initialize the NMRL file to empty before placing any object code into it. This is similar to the $USLINIT directive in FORTRAN 77/V. NATIVE LANGUAGE SUPPORT - The $NLS_SOURCE directive turns on or off special processing to handle foreign language text appearing in the source program. The processing applies to input character strings or output character strings and character constants. EXTENDED RANGE DO LOOPS - Execution may be transferred out of, or into, the range of a DO loop. LIST-DIRECTED INTERNAL MEMORY I/O - Internal files may be used with list-directed READ or WRITE. RECL= ON SEQUENTIAL OPEN OF FILES - When a sequential file is opened the record length may now be specified. UNIT = SPECIFIER IN I/O ALLOWS RECORD NUMBER QUALIFIER - For direct file access a record number may be included in the "UNIT=" parameter by following the unit number with @rn where rn is a constant or expression that specifies the record number. For example, WRITE(UNIT=3@20...will write to unit 3, record 20. DEC/VMS EXTENSIONS BYTE DATATYPE - The BYTE statement is an HP extension to the ANSI 77 standard and has the same effect as the LOGICAL*1 statement. VARIABLE EXPRESSIONS IN FORMAT STATEMENTS - This is Phase I of this feature. In this first phase integer variables, integer constants and character constants can be used in format strings to allow variable formats. An example is FORMAT (I<ISIZE>), where ISIZE is an integer variable. PARENTHETICAL EXPRESSIONS IN PARAMETER STATEMENTS - A new PARAMETER statement syntax is implemented where the list is not bounded by parentheses, and the form of the constant determines the data type of the variable. An example is PARAMETER ii = 'ab', where ii is type character*2. PARAMETER STATEMENT ALLOWS INTRINSIC CALLS - ABS, CHAR, DIM, DPROD, IAND, ICHAR, IEOR, IMAG, IOR, ISHFT, LGE, LGT, LLE, LLT, MAX, MIN, MOD, NINIT, NOT, IXOR, AND CONJG are the intrinsics with constant arguments that are allowed in the PARAMETER statement. OCTAL, HEX, ASCII, AND HOLLERITH COMPATIBILITY - Hollerith, ASCII, octal and hexadecimal constants are considered typeless constants. Typeless constants do not undergo the type checking that normally prevents the use of expressions such as i='A000'+1 and c="30" X, where i is integer and c is character. The compiler will now accept the 'xx'[HO] syntax as well as the currently accepted [HO]'xx'. LOOSER TYPE CHECKING, AUTOMATIC TYPE CONVERSIONS - There is looser type checking for assignments, expressions, array boundaries and subscripts. LENGTH SPECIFIER FOLLOWING SYMBOLIC NAME OR FUNCTION - In a type statement, an item may be followed by a length specifier. This specification overrides the length implied by the type statement. For example, in the statement INTEGER IA,II*2, variable IA is type integer*4 by default, but variable II is overridden and becomes type integer*2. "$" MAY APPEAR IN SYMBOLIC NAMES - except in the first character of a variable or program unit name. VARIABLE MAY BE INITIALIZED IN TYPE STATEMENT - Variables may be initialized in type statements by enclosing the initialization values with slashes, for example INTEGER A/2/. TRANSCENDENTAL FUNCTIONS ACCEPT DEGREE ARGUMENTS - Functions Sine, Cosine, Tangent, Arcsine, Arccosine and Arctangent accept an argument in degrees expressed in radians. HP 1000 EXTENSIONS ARITHMETIC IF ALLOWED TO HAVE 2 LABELS - An arithmetic IF statement may have two labels instead of three. The first label is where execution branches to for a negative value and the second label is where execution branches to for a zero or positive value. GAUSSIAN AND POISSON RANDOM NUMBER ROUTINES - Two new random number generator functions are available. Function GRAN generates Gaussian random single precision real numbers and function IRANP generates Poisson-distributed integer random numbers. For more information on all of these enhancements please refer to the updates to the FORTRAN 77/XL Reference Manual Kit (P/N 31501-60002).