Hi Thiemo, thanks a lot for the explanations! On Tue, Mar 18, 2003 at 08:08:41PM +0100, Thiemo Seufer wrote: > This would be nice, but older compilers don't have -march/-mtune. > IIRC gcc 3.0.X is the first one to employ these. Similiar for -mabi. I don't care about old compilers at the moment ;) [..snip..] > -mabi=FOO: > Produce, hosted on a multi ABI system, a userland binary with the lowest > possible ISA for the selected ABI. > > Then there are optimizations for different CPUs. > > -march=BAR: > Allow opcodes for CPU BAR in addition to the ISA ones. > > -mtune=BAZ: > Optimize opcode scheduling for CPU BAZ. So to build kernels for say IP22 R5k I'd change the current GCCFLAGS += -mcpu=r5000 -mips2 -Wa,--trap to GCCFLAGS += -mabi=o32 -march=R5000 -mtune=R5000 -Wa,--trap where as for R4X00 I use GCCFLAGS += -mabi=o32 -march=R4600 -mtune=R4600 -Wa,--trap Correct? -- Guido
