Features in f77 4.0 that are New Since 3.0/3.0.1 (Fortran User's Guide)

Fortran User's Guide

Features in `f77` 4.0 that are New Since 3.0/3.0.1

f77 4.0 includes the following features that are new or changed since 3.0/3.0.1:

The DOSERIAL and DOSERIAL* parallel directives have been added, and the DOALL directive expanded.
A directive for unrolling loops has been added.
The -Idir option now also affects the f77 INCLUDE statement, not only the preprocessor #include directive.
The Incremental Linker is available. It provides faster linking and speeds up development.
The -oldstruct command-line option has been deleted.
The following new synonyms have been added: -xautopar, -xdepend, -xexplicitpar, -xloopinfo, -xparallel, -xreduction, and -xvpara.
The -stackvar restrictions EQUIVALANCE, NAMELIST, STRUCTURE, and RECORD have been removed.
New options have been added (and some changed):

Table B-1 New Features in f77 4.0 Since 3.0/3.0.1


`-arg=local`	Pass by value result.
`-copyargs`	Allow assignment to constant arguments.
`-dbl`	Double the default size for integers, reals, and so forth.
`-ext_names=e`	Make external names with or without underscores.
`-fns`	Turn on SPARC non-standard floating-point mode (SPARC).
`-fround=r`	Set the IEEE rounding mode in effect at startup (SPARC).
`-fsimple`[`=n`]	Allow levels of simple floating-point model.
`-ftrap=t`	Set the IEEE trapping mode in effect at startup (SPARC).
`-mp=x`	Use either Sun-style or Cray-style MP directives (SPARC).
`-O5`	Attempt the highest level of optimization.
`-pad=`p	Pad local variables or common blocks
`-vax=v`	Specify a choice of VMS features to use.
`-xarch=a`	Limit the set of instructions the compiler may use (SPARC).
`-xcache`=`c`	Define the cache properties for use by the optimizer (SPARC).
`-xchip=c`	Specify the target processor for use by the optimizer (SPARC).
`-xhelp=h`	Show help information for `README` file or for options (flags).
`-xildoff`	Turn off the Incremental Linker (SPARC).
`-xildon`	Turn on the Incremental Linker (SPARC).
`-xprofile=p`	Collect data for a profile or use a profile to optimize (SPARC).
`-xregs=r`	Specify the usage of registers for the generated code (SPARC).
`-xsafe=mem`	Allow compiler to assume no memory-based traps (SPARC).
`-xspace`	Do no optimizations that increase the code size (SPARC).
`-xtarget=t`	Specify target system for instruction set (SPARC).
`-ztext`	Do not make the library if relocations remain.

DO-loop code is now implemented differently to allow better optimization and loop parallelization. Legal DO-loops behave exactly the same as before; however, illegal DO-loops--zero-step, loop variable modified within the loop--may display different behavior.

Full 64-bit integers have been added. With -dbl, integers not declared with a specified size are turned into full 64-bit integers.

The following libV77 library routines: date, mvbits, ran, and secnds, are now folded into the libF77 library. That is, you no longer need to compile with the -lV77 option to get these routines.

The OPEN statement now contains a new keyword specifier, ACTION=act, where act is READ, WRITE, or READWRITE.