HP 3000 Manuals HP 3000 Manuals
New Features
Many features not available in HP FORTRAN 77/V are added in HP FORTRAN
77/iX. These are outlined below. For complete information about any of
these features, see the HP FORTRAN 77/iX Reference manual.
HP3000_16 Directive
The HP3000_16 compiler directive specifies various options for
compatibility with HP FORTRAN 77/V. These are the options:
$HP3000_16 REALS Specifies MPE V format for floating-point
data.
$HP3000_16 ALIGNMENT Specifies alignment of noncharacter data on
16-bit boundaries.
$HP3000_16 STRING_MOVE Specifies that overlapping character
strings are moved.
$HP3000_16 ON Specifies all the above options.
$HP3000_16 Same as $HP3000_16 ON.
$HP3000_16 OFF Specifies none of the above options.
These options apply to an entire program unit and may not be changed
within a program unit. For best results, compile entire programs with a
consistent list of HP3000_16 options either by placing the directive
before any other statements at the beginning of each source file, or by
passing the option to the compiler through the INFO string.
OPTIMIZE Directive
The OPTIMIZE directive specifies optimization of object code. The
directive provides these levels of code optimization:
$OPTIMIZE OFF Level 0 optimization (does no
optimizing). This is the
default.
$OPTIMIZE ON Same as $OPTIMIZE LEVEL2.
$OPTIMIZE LEVEL1 Optimizes only within each basic
block.
$OPTIMIZE LEVEL2 Level 2 optimization with the
following ASSUME settings:
ASSUME_NO_PARAMETER_OVERLAPS ON
ASSUME_PARM_TYPES_MATCHED ON
ASSUME_NO_EXTERNAL_PARMS ON
ASSUME_NO_SIDE_EFFECTS OFF
See below for ASSUME
descriptions.
$OPTIMIZE LEVEL2_MIN Level 2 optimization with all the
ASSUME settings at OFF.
$OPTIMIZE LEVEL2_MAX Level 2 optimization with all the
ASSUME settings at ON.
$OPTIMIZE ASSUME_NO_PARAMETER_OVERLAPS No actual parameters passed
to a subprogram overlap each
other.
$OPTIMIZE ASSUME_NO_SIDE_EFFECTS The current subprogram
changes only local
variables. It does not
change any variables in
COMMON, nor does it change
parameters.
$OPTIMIZE ASSUME_PARM_TYPES_MATCHED All of the actual parameters
passed were the type
expected by this subprogram.
$OPTIMIZE ASSUME_NO_EXTERNAL_PARMS None of the parameters
passed to the current
subprogram are from an
external space, that is,
different from the user's
own data space. Parameters
can come from another space
if they come from operating
system space or if they are
in a space shared by other
users.
For further details about the OPTIMIZE directive and its options, see the
HP FORTRAN 77/iX Programmer's Guide.
SYMDEBUG Directive
The MPE/iX operating system provides symbolic debugging for HP FORTRAN
77/iX programs. If the SYMDEBUG directive is used, the compiler inserts
debugging information in the object file. Symbolic debugging is not
compatible with code optimization; therefore, do not use both $SYMDEBUG
and $OPTIMIZE.
LOCALITY Directive
The LOCALITY directive allows you to group procedures together in virtual
memory to maximize throughput and minimize system overhead. LOCALITY is
similar to the SEGMENT directive of HP FORTRAN 77/V. However, unlike
SEGMENT, which is required in HP FORTRAN 77/V when large programs must be
broken into segments, the LOCALITY directive is not required in HP
FORTRAN 77/iX. HP FORTRAN 77/iX handles memory management transparently.
EXTERNAL_ALIAS and LITERAL_ALIAS Directives
The EXTERNAL_ALIAS and LITERAL_ALIAS directives allow you to redefine the
names of functions and subroutines within a program unit.
UPPERCASE and LOWERCASE Directives
The UPPERCASE and LOWERCASE directives allow you to turn on or off
shifting to uppercase or lowercase in FORTRAN 77 external names.
ON Statement and INTEGER*2 Conditions
In MPE/iX, ON statements specifying trap handling for INTEGER*2
conditions are enabled only when the $CHECK_OVERFLOW INTEGER_2 option
(which is the default) is on. This restriction also applies to trap
handling for INTEGER conditions if the $SHORT option is on.