gccV850

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NEC V850 options options

The following are the ‘`-m`’ options for V850 implementations.

`-mlong-calls`
-mno-long-calls

Treat all calls as being far away (or near). If calls are assumed to be far away, the compiler will always load the functions address up into a register, and call indirect through the pointer.

-mno-ep
-mep

Do not optimize (or optimize) basic blocks that use the same index pointer 4 or more times to copy pointer into the ep register, and use the shorter sld and sst 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 prolog and epilog 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 register ep 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 register gp 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.

-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 will cause r2 and r5 to be used in the code generated by the compiler. This setting is the default.

-mno-app-regs

This option will cause r2 and r5 to be treated as fixed registers.

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