Is it safe to save just part of registers in interrupt/exception handler?
Ian Lance Taylor
Fri Jun 13 14:06:00 GMT 2008
"PRC" <firstname.lastname@example.org> writes:
> The MIPS ABI document says:
> For non-leaf function,$31 must be saved. If any of
> $16..$23 or$29..$31 is changed within the called function, it must be saved
> in the stack frame before use and restored from the stack frame before re-
> turn from the function.
> My interrupt/exception handler contains two parts: one written in assembly
> and the other written in C. The ASM handler does some simple work like
> saving status, epc and gerneral registers and then jumps/calls to the C handler
> to do more complex work. Since MIPS ABI guarantees $16~$23 and $29~$31 are saved
> in C functions if they are used, is it safe to save only those registers except $16~$23 and $29~$31 in ASM handler?
In general, yes.
More information about the Gcc-help