V850 Options#
These -m
options are defined for V850 implementations:
- -mlong-calls, -mno-long-calls#
Treat all calls as being far away (near). If calls are assumed to be far away, the compiler always loads the function’s address into a register, and calls indirect through the pointer.
- -mno-ep, -mep#
Do not optimize (do optimize) basic blocks that use the same index pointer 4 or more times to copy pointer into the
ep
register, and use the shortersld
andsst
instructions. The-mep
option is on by default if you optimize.
- -mno-prolog-function, -mprolog-function#
Do not use (do use) external functions to save and restore registers at the prologue and epilogue of a function. The external functions are slower, but use less code space if more than one function saves the same number of registers. The
-mprolog-function
option is on by default if you optimize.
- -mspace#
Try to make the code as small as possible. At present, this just turns on the
-mep
and-mprolog-function
options.
- -mtda=n#
Put static or global variables whose size is
n
bytes or less into the tiny data area that registerep
points to. The tiny data area can hold up to 256 bytes in total (128 bytes for byte references).
- -msda=n#
Put static or global variables whose size is
n
bytes or less into the small data area that registergp
points to. The small data area can hold up to 64 kilobytes.
- -mzda=n#
Put static or global variables whose size is
n
bytes or less into the first 32 kilobytes of memory.
- -mv850#
Specify that the target processor is the V850.
- -mv850e3v5#
Specify that the target processor is the V850E3V5. The preprocessor constant
__v850e3v5__
is defined if this option is used.
- -mv850e2v4#
Specify that the target processor is the V850E3V5. This is an alias for the
-mv850e3v5
option.
- -mv850e2v3#
Specify that the target processor is the V850E2V3. The preprocessor constant
__v850e2v3__
is defined if this option is used.
- -mv850e2#
Specify that the target processor is the V850E2. The preprocessor constant
__v850e2__
is defined if this option is used.
- -mv850e1#
Specify that the target processor is the V850E1. The preprocessor constants
__v850e1__
and__v850e__
are defined if this option is used.
- -mv850es#
Specify that the target processor is the V850ES. This is an alias for the
-mv850e1
option.
- -mv850e#
Specify that the target processor is the V850E. The preprocessor constant
__v850e__
is defined if this option is used.If neither
-mv850
nor-mv850e
nor-mv850e1
nor-mv850e2
nor-mv850e2v3
nor-mv850e3v5
are defined then a default target processor is chosen and the relevant__v850*__
preprocessor constant is defined.The preprocessor constants
__v850
and__v851__
are always defined, regardless of which processor variant is the target.
- -mdisable-callt, -mno-disable-callt#
This option suppresses generation of the
CALLT
instruction for the v850e, v850e1, v850e2, v850e2v3 and v850e3v5 flavors of the v850 architecture.This option is enabled by default when the RH850 ABI is in use (see
-mrh850-abi
), and disabled by default when the GCC ABI is in use. IfCALLT
instructions are being generated then the C preprocessor symbol__V850_CALLT__
is defined.
- -mlong-jumps, -mno-long-jumps#
Disable (or re-enable) the generation of PC-relative jump instructions.
- -msoft-float, -mhard-float#
Disable (or re-enable) the generation of hardware floating point instructions. This option is only significant when the target architecture is
V850E2V3
or higher. If hardware floating point instructions are being generated then the C preprocessor symbol__FPU_OK__
is defined, otherwise the symbol__NO_FPU__
is defined.
- -mloop#
Enables the use of the e3v5 LOOP instruction. The use of this instruction is not enabled by default when the e3v5 architecture is selected because its use is still experimental.
- -mrh850-abi, -mghs#
Enables support for the RH850 version of the V850 ABI. This is the default. With this version of the ABI the following rules apply:
Integer sized structures and unions are returned via a memory pointer rather than a register.
Large structures and unions (more than 8 bytes in size) are passed by value.
Functions are aligned to 16-bit boundaries.
The
-m8byte-align
command-line option is supported.The
-mdisable-callt
command-line option is enabled by default. The-mno-disable-callt
command-line option is not supported.
When this version of the ABI is enabled the C preprocessor symbol
__V850_RH850_ABI__
is defined.
- -mgcc-abi#
Enables support for the old GCC version of the V850 ABI. With this version of the ABI the following rules apply:
Integer sized structures and unions are returned in register
r10
.Large structures and unions (more than 8 bytes in size) are passed by reference.
Functions are aligned to 32-bit boundaries, unless optimizing for size.
The
-m8byte-align
command-line option is not supported.The
-mdisable-callt
command-line option is supported but not enabled by default.
When this version of the ABI is enabled the C preprocessor symbol
__V850_GCC_ABI__
is defined.
- -m8byte-align, -mno-8byte-align#
Enables support for
double
andlong long
types to be aligned on 8-byte boundaries. The default is to restrict the alignment of all objects to at most 4-bytes. When-m8byte-align
is in effect the C preprocessor symbol__V850_8BYTE_ALIGN__
is defined.
- -mbig-switch#
Generate code suitable for big switch tables. Use this option only if the assembler/linker complain about out of range branches within a switch table.
- -mapp-regs#
This option causes r2 and r5 to be used in the code generated by the compiler. This setting is the default.
- -mno-app-regs#
This option causes r2 and r5 to be treated as fixed registers.