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HPPA
Options
The following ‘-m’
options are defined for the HPPA family of computers.
-mpa-risc-1-0
Generate code
for a PA 1.0 processor.
-mpa-risc-1-1
Generate code
for a PA 1.1 processor.
-mjump-in-delay
Fill delay slots
of function calls with unconditional jump instructions by modifying the
return pointer for the function call to be the target of the conditional
jump.
-mdisable-fpregs
Prevent floating
point registers from being used in any manner. This is necessary for compiling
kernels which perform lazy context switching of floating point registers.
If you use this option and attempt to perform floating point operations,
the compiler will abort.
-mdisable-indexing
Prevent the compiler
from using indexing address modes. This avoids some rather obscure problems
when compiling MIG generated code under MACH.
-mno-space-regs
Generate code
that assumes the target has no space registers.
This allows GCC to generate
faster indirect calls and use unscaled index address modes.
Such code is suitable for
level 0 PA systems and kernels.
-mfast-indirect-calls
Generate code
that assumes calls never cross space boundaries. This allows GCC to emit
code which performs faster indirect calls.
This option will not work
in the presense of shared libraries or nested functions.
-mspace
Optimize for space
rather than execution time. Currently this only enables out of line function
prologues and epilogues. This option is incompatible with PIC code generation
and profiling.
-mlong-load-store
Generate 3-instruction
load and store sequences as some-times required by the HPUX 10 linker.
This is equivalent to the ‘+k’
option to the HP compilers.
-mportable-runtime
Use the portable
calling conventions proposed by HP for ELF systems.
-mgas
Enable the use
of assembler directives only GAS understands.
-mschedule=cpu type
Schedule code
according to the constraints for the machine type cpu
type. The
choices for cpu
type are
700
for 7n0
ma-chines, 7100
for 7n5
machines, and 7100
for 7n2
machines. 7100
is the default for cpu
type.
- Note:
The 7100LC
scheduling information is incomplete and using 7100LC
often leads to bad schedules. For now it’s probably best to use 7100
instead of 7100LC
for the 7n2
machines.
-mlinker-opt
Enable the optimization
pass in the HPUX linker.
- Note:
This makes symbolic debugging impossible. It also triggers a bug in the
HPUX 8 and HPUX 9 linkers in which they give bogus error messages when
linking some programs.
-msoft-float
Generate output
containing library calls for floating point.
- Warning:
The requisite libraries are not available for all HPPA targets.
Normally the facilities of the machine’s usual C compiler are used, but
this cannot be done directly in cross-compilation. You must make your own
arrangements to provide suitable library functions for cross-compilation.
The embedded target hppa1.1-*-pro
does provide software floating point support.
-msoft-float
changes the calling convention in the output file; therefore, it is only
useful if you compile all of a program with this option. In particular,
you need to compile libgcc.a,
the library that comes with GNU CC, with -msoft-float
in order for this to work.