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 choices for cpu type are `r2000', `r3000',
`r3900', `r4000', `r4100', `r4300', `r4400',
`r4600', `r4650', `r5000', `r6000', `r8000',
and `orion'. Additionally, the `r2000', `r3000',
`r4000', `r5000', and `r6000' can be abbreviated as
`r2k' (or `r2K'), `r3k', etc. 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 a `-mipsX'
or `-mabi' switch being used.
-mips1
Issue instructions from level 1 of the MIPS ISA. This is the default.
`r3000' is the default cpu type at this ISA level.
-mips2
Issue instructions from level 2 of the MIPS ISA (branch likely, square
root instructions). `r6000' is the default cpu type at this
ISA level.
-mips3
Issue instructions from level 3 of the MIPS ISA (64 bit instructions).
`r4000' is the default cpu type at this ISA level.
-mips4
Issue instructions from level 4 of the MIPS ISA (conditional move,
prefetch, enhanced FPU instructions). `r8000' is the default
cpu type at this ISA level.
-mfp32
Assume that 32 32-bit floating point registers are available. This is
the default.
-mfp64
Assume that 32 64-bit floating point registers are available. This is
the default when the `-mips3' option is used.
-mgp32
Assume that 32 32-bit general purpose registers are available. This is
the default.
-mgp64
Assume that 32 64-bit general purpose registers are available. This is
the default when the `-mips3' option is used.
-mint64
Force int and long types to be 64 bits wide. See `-mlong32' for an
explanation of the default, and the width of pointers.
-mlong64
Force long types to be 64 bits wide. See `-mlong32' for an
explanation of the default, and the width of pointers.
-mlong32
Force long, int, and pointer types to be 32 bits wide.
If none of `-mlong32', `-mlong64', or `-mint64' are set,
the size of ints, longs, and pointers depends on the ABI and ISA choosen.
For `-mabi=32', and `-mabi=n32', ints and longs are 32 bits
wide. For `-mabi=64', ints are 32 bits, and longs are 64 bits wide.
For `-mabi=eabi' and either `-mips1' or `-mips2', ints
and longs are 32 bits wide. For `-mabi=eabi' and higher ISAs, ints
are 32 bits, and longs are 64 bits wide. The width of pointer types is
the smaller of the width of longs or the width of general purpose
registers (which in turn depends on the ISA).
-mabi=32
-mabi=o64
-mabi=n32
-mabi=64
-mabi=eabi
Generate code for the indicated ABI. The default instruction level is
`-mips1' for `32', `-mips3' for `n32', and
`-mips4' otherwise. Conversely, with `-mips1' or
`-mips2', the default ABI is `32'; otherwise, the default ABI
is `64'.
-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. Also, this is
the default if the configure option `--with-gnu-as' is used.
-msplit-addresses
-mno-split-addresses
Generate code to load the high and low parts of address constants separately.
This allows gcc to optimize away redundant loads of the high order
bits of addresses. This optimization requires GNU as and GNU ld.
This optimization is enabled by default for some embedded targets where
GNU as and GNU ld are standard.
-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 only known assembler that supports this option
is the Algorithmics assembler.
-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 GCC.
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.
-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
-mno-long-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.
-membedded-pic
-mno-embedded-pic
Generate PIC code suitable for some embedded systems. All calls are
made using PC relative address, and all data is addressed using the $gp
register. No more than 65536 bytes of global data may be used. This
requires GNU as and GNU ld which do most of the work. This currently
only works on targets which use ECOFF; it does not work with ELF.
-membedded-data
-mno-embedded-data
Allocate variables to the read-only data section first if possible, then
next in the small data section if possible, otherwise in data. This gives
slightly slower code than the default, but reduces the amount of RAM required
when executing, and thus may be preferred for some embedded systems.
-msingle-float
-mdouble-float
The `-msingle-float' switch tells gcc to assume that the floating
point coprocessor only supports single precision operations, as on the
`r4650' chip. The `-mdouble-float' switch permits gcc to use
double precision operations. This is the default.
-mmad
-mno-mad
Permit use of the `mad', `madu' and `mul' instructions,
as on the `r4650' chip.
-m4650
Turns on `-msingle-float', `-mmad', and, at least for now,
`-mcpu=r4650'.
-mips16
-mno-mips16
Enable 16-bit instructions.
-mentry
Use the entry and exit pseudo ops. This option can only be used with
`-mips16'.
-EL
Compile code for the processor in little endian mode.
The requisite libraries are assumed to exist.
-EB
Compile code for the processor in big endian mode.
The requisite libraries are assumed to exist.
-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 its preprocessor over user
assembler files (with a `.s' suffix) when assembling them.