Using the GNU Compiler Collection (GCC): M32R/D Options

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3.18.21 M32R/D Options

These -m options are defined for Renesas M32R/D architectures:

-m32r2

Generate code for the M32R/2.

-m32rx

Generate code for the M32R/X.

-m32r

Generate code for the M32R. This is the default.

-mmodel=small

Assume all objects live in the lower 16MB of memory (so that their addresses can be loaded with the ld24 instruction), and assume all subroutines are reachable with the bl instruction. This is the default.

The addressability of a particular object can be set with the model attribute.

-mmodel=medium

Assume objects may be anywhere in the 32-bit address space (the compiler generates seth/add3 instructions to load their addresses), and assume all subroutines are reachable with the bl instruction.

-mmodel=large

Assume objects may be anywhere in the 32-bit address space (the compiler generates seth/add3 instructions to load their addresses), and assume subroutines may not be reachable with the bl instruction (the compiler generates the much slower seth/add3/jl instruction sequence).

-msdata=none

Disable use of the small data area. Variables are put into one of .data, .bss, or .rodata (unless the section attribute has been specified). This is the default.

The small data area consists of sections .sdata and .sbss. Objects may be explicitly put in the small data area with the section attribute using one of these sections.

-msdata=sdata

Put small global and static data in the small data area, but do not generate special code to reference them.

-msdata=use

Put small global and static data in the small data area, and generate special instructions to reference them.

-G num

Put global and static objects less than or equal to num bytes into the small data or BSS sections instead of the normal data or BSS sections. The default value of num is 8. The -msdata option must be set to one of ‘sdata’ or ‘use’ for this option to have any effect.

All modules should be compiled with the same -G num value. Compiling with different values of num may or may not work; if it doesn’t the linker gives an error message—incorrect code is not generated.

-mdebug

Makes the M32R-specific code in the compiler display some statistics that might help in debugging programs.

-malign-loops

Align all loops to a 32-byte boundary.

-mno-align-loops

Do not enforce a 32-byte alignment for loops. This is the default.

-missue-rate=number

Issue number instructions per cycle. number can only be 1 or 2.

-mbranch-cost=number

number can only be 1 or 2. If it is 1 then branches are preferred over conditional code, if it is 2, then the opposite applies.

-mflush-trap=number

Specifies the trap number to use to flush the cache. The default is 12. Valid numbers are between 0 and 15 inclusive.

-mno-flush-trap

Specifies that the cache cannot be flushed by using a trap.

-mflush-func=name

Specifies the name of the operating system function to call to flush the cache. The default is ‘_flush_cache’, but a function call is only used if a trap is not available.

-mno-flush-func

Indicates that there is no OS function for flushing the cache.

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