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These `-m' options are defined for the MIPS family of computers:
-mcpu=cpu type
- Assume the defaults for the machine type cpu type when
scheduling instructions. The default cpu type is
`default', which picks the longest cycles times for any of the
machines, in order that the code run at reasonable rates on all MIPS
cpu's. Other choices for cpu type are `r2000',
`r3000', `r4000', and `r6000'. While picking a
specific cpu type will schedule things appropriately for that
particular chip, the compiler will not generate any code that does not
meet level 1 of the MIPS ISA (instruction set architecture) without
the `-mips2' or `-mips3' switches being used.
-mips2
- Issue instructions from level 2 of the MIPS ISA (branch likely, square
root instructions). The `-mcpu=r4000' or `-mcpu=r6000'
switch must be used in conjunction with `-mips2'.
-mips3
- Issue instructions from level 3 of the MIPS ISA (64 bit instructions).
You must use the `-mcpu=r4000' switch along with `-mips3'.
-mint64
-mlong64
-mlonglong128
- These options don't work at present.
-mmips-as
- Generate code for the MIPS assembler, and invoke `mips-tfile' to
add normal debug information. This is the default for all
platforms except for the OSF/1 reference platform, using the OSF/rose
object format. If the either of the `-gstabs' or `-gstabs+'
switches are used, the `mips-tfile' program will encapsulate the
stabs within MIPS ECOFF.
-mgas
- Generate code for the GNU assembler. This is the default on the OSF/1
reference platform, using the OSF/rose object format.
-mrnames
-mno-rnames
- The `-mrnames' switch says to output code using the MIPS software
names for the registers, instead of the hardware names (ie, a0
instead of $4). The GNU assembler does not support the
`-mrnames' switch, and the MIPS assembler will be instructed to
run the MIPS C preprocessor over the source file. The
`-mno-rnames' switch is default.
-mgpopt
-mno-gpopt
- The `-mgpopt' switch says to write all of the data declarations
before the instructions in the text section, this allows the MIPS
assembler to generate one word memory references instead of using two
words for short global or static data items. This is on by default if
optimization is selected.
-mstats
-mno-stats
- For each non-inline function processed, the `-mstats' switch
causes the compiler to emit one line to the standard error file to
print statistics about the program (number of registers saved, stack
size, etc.).
-mmemcpy
-mno-memcpy
- The `-mmemcpy' switch makes all block moves call the appropriate
string function (`memcpy' or `bcopy') instead of possibly
generating inline code.
-mmips-tfile
-mno-mips-tfile
- The `-mno-mips-tfile' switch causes the compiler not
postprocess the object file with the `mips-tfile' program,
after the MIPS assembler has generated it to add debug support. If
`mips-tfile' is not run, then no local variables will be
available to the debugger. In addition, `stage2' and
`stage3' objects will have the temporary file names passed to the
assembler embedded in the object file, which means the objects will
not compare the same. The `-mno-mips-tfile' switch should only
be used when there are bugs in the `mips-tfile' program that
prevents compilation.
-msoft-float
- Generate output containing library calls for floating point.
Warning: the requisite libraries are not part of GNU CC.
Normally the facilities of the machine's usual C compiler are used, but
this can't be done directly in cross-compilation. You must make your
own arrangements to provide suitable library functions for
cross-compilation.
-mhard-float
- Generate output containing floating point instructions. This is the
default if you use the unmodified sources.
-mfp64
- Assume that the FR bit in the status word is on, and that there
are 32 64-bit floating point registers, instead of 32 32-bit floating
point registers. You must also specify the `-mcpu=r4000' and
`-mips3' switches.
-mfp32
- Assume that there are 32 32-bit floating point registers. This is the
default.
-mabicalls
-mno-abicalls
- Emit (or do not emit) the pseudo operations `.abicalls',
`.cpload', and `.cprestore' that some System V.4 ports use for
position independent code.
-mlong-calls
-mlong-calls
- Do all calls with the `JALR' instruction, which requires
loading up a function's address into a register before the call.
You need to use this switch, if you call outside of the current
512 megabyte segment to functions that are not through pointers.
-mhalf-pic
-mno-half-pic
- Put pointers to extern references into the data section and load them
up, rather than put the references in the text section.
-G num
-
Put global and static items less than or equal to num bytes into
the small data or bss sections instead of the normal data or bss
section. This allows the assembler to emit one word memory reference
instructions based on the global pointer (gp or $28),
instead of the normal two words used. By default, num is 8 when
the MIPS assembler is used, and 0 when the GNU assembler is used. The
`-G num' switch is also passed to the assembler and linker.
All modules should be compiled with the same `-G num'
value.
-nocpp
- Tell the MIPS assembler to not run it's preprocessor over user
assembler files (with a `.s' suffix) when assembling them.
These options are defined by the macro
TARGET_SWITCHES in the machine description. The default for the
options is also defined by that macro, which enables you to change the
defaults.
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