SPARC Options - Using the GNU Compiler Collection (GCC) (original) (raw)

-mno-app-regs

-mapp-regs

Specify -mapp-regs to generate output using the global registers 2 through 4, which the SPARC SVR4 ABI reserves for applications. This is the default, except on Solaris.

To be fully SVR4 ABI compliant at the cost of some performance loss, specify -mno-app-regs. You should compile libraries and system software with this option.

-mfpu

-mhard-float

Generate output containing floating point instructions. This is the default.

-mno-fpu

-msoft-float

Generate output containing library calls for floating point. Warning: the requisite libraries are not available for all SPARC targets. Normally the facilities of the machine's usual C compiler are used, but this cannot be done directly in cross-compilation. You must make your own arrangements to provide suitable library functions for cross-compilation. The embedded targets `sparc-*-aout' and `sparclite-*-*' do provide software floating point support.

-msoft-float changes the calling convention in the output file; therefore, it is only useful if you compile all of a program with this option. In particular, you need to compile libgcc.a, the library that comes with GCC, with -msoft-float in order for this to work.

-mhard-quad-float

Generate output containing quad-word (long double) floating point instructions.

-msoft-quad-float

Generate output containing library calls for quad-word (long double) floating point instructions. The functions called are those specified in the SPARC ABI. This is the default.

As of this writing, there are no sparc implementations that have hardware support for the quad-word floating point instructions. They all invoke a trap handler for one of these instructions, and then the trap handler emulates the effect of the instruction. Because of the trap handler overhead, this is much slower than calling the ABI library routines. Thus the-msoft-quad-float option is the default.

-mno-flat

-mflat

With -mflat, the compiler does not generate save/restore instructions and will use a “flat” or single register window calling convention. This model uses %i7 as the frame pointer and is compatible with the normal register window model. Code from either may be intermixed. The local registers and the input registers (0–5) are still treated as “call saved” registers and will be saved on the stack as necessary.

With -mno-flat (the default), the compiler emits save/restore instructions (except for leaf functions) and is the normal mode of operation.

-mno-unaligned-doubles

-munaligned-doubles

Assume that doubles have 8 byte alignment. This is the default.

With -munaligned-doubles, GCC assumes that doubles have 8 byte alignment only if they are contained in another type, or if they have an absolute address. Otherwise, it assumes they have 4 byte alignment. Specifying this option avoids some rare compatibility problems with code generated by other compilers. It is not the default because it results in a performance loss, especially for floating point code.

-mno-faster-structs

-mfaster-structs

With -mfaster-structs, the compiler assumes that structures should have 8 byte alignment. This enables the use of pairs ofldd and std instructions for copies in structure assignment, in place of twice as many ld and st pairs. However, the use of this changed alignment directly violates the SPARC ABI. Thus, it's intended only for use on targets where the developer acknowledges that their resulting code will not be directly in line with the rules of the ABI.

-mimpure-text

-mimpure-text, used in addition to -shared, tells the compiler to not pass -z text to the linker when linking a shared object. Using this option, you can link position-dependent code into a shared object.

-mimpure-text suppresses the “relocations remain against allocatable but non-writable sections” linker error message. However, the necessary relocations will trigger copy-on-write, and the shared object is not actually shared across processes. Instead of using -mimpure-text, you should compile all source code with-fpic or -fPIC.

This option is only available on SunOS and Solaris.

-mv8

-msparclite

These two options select variations on the SPARC architecture.

By default (unless specifically configured for the Fujitsu SPARClite), GCC generates code for the v7 variant of the SPARC architecture.

-mv8 will give you SPARC v8 code. The only difference from v7 code is that the compiler emits the integer multiply and integer divide instructions which exist in SPARC v8 but not in SPARC v7.

-msparclite will give you SPARClite code. This adds the integer multiply, integer divide step and scan (ffs) instructions which exist in SPARClite but not in SPARC v7.

These options are deprecated and will be deleted in a future GCC release. They have been replaced with -mcpu=xxx.

-mcypress

-msupersparc

These two options select the processor for which the code is optimized.

With -mcypress (the default), the compiler optimizes code for the Cypress CY7C602 chip, as used in the SPARCStation/SPARCServer 3xx series. This is also appropriate for the older SPARCStation 1, 2, IPX etc.

With -msupersparc the compiler optimizes code for the SuperSPARC cpu, as used in the SPARCStation 10, 1000 and 2000 series. This flag also enables use of the full SPARC v8 instruction set.

These options are deprecated and will be deleted in a future GCC release. They have been replaced with -mcpu=xxx.

-mcpu=cpu_type

Set the instruction set, register set, and instruction scheduling parameters for machine type cpu_type. Supported values for cpu_type are `v7', `cypress', `v8', `supersparc', `sparclite', `hypersparc', `sparclite86x', `f930', `f934', `sparclet', `tsc701', `v9', `ultrasparc', and `ultrasparc3'.

Default instruction scheduling parameters are used for values that select an architecture and not an implementation. These are `v7', `v8', `sparclite', `sparclet', `v9'.

Here is a list of each supported architecture and their supported implementations.

          v7:             cypress
          v8:             supersparc, hypersparc
          sparclite:      f930, f934, sparclite86x
          sparclet:       tsc701
          v9:             ultrasparc, ultrasparc3
 

-mtune=cpu_type

Set the instruction scheduling parameters for machine typecpu_type, but do not set the instruction set or register set that the option -mcpu=cpu_type would.

The same values for -mcpu=cpu_type can be used for-mtune=cpu_type, but the only useful values are those that select a particular cpu implementation. Those are `cypress', `supersparc', `hypersparc', `f930', `f934', `sparclite86x', `tsc701', `ultrasparc', and `ultrasparc3'.

These `-m' switches are supported in addition to the above on the SPARCLET processor.

These `-m' switches are supported in addition to the above on SPARC V9 processors in 64-bit environments.