On Mon, Apr 16, 2007 at 01:44:22PM +0100, Thiemo Seufer wrote: > Zhang Fuxin wrote: > > >> +cflags-$(CONFIG_CPU_LOONGSON2) += -march=r4600 -Wa,--trap > > > > > > I wonder why this is r4600. I heard the Loongson2 is MIPS IV compatible, > > > so r5000 / r8000 / r10000 would be better choices. > > > > Presently Loongson-2E is nearly MIPS III compatible(with some > > self-defined extensions), next version will be mips64 release2 compatible. > > I see. > > > -march=r4600 is inherited from loongson-1, -march=mips3 might be a > > better choice. > > Maybe. The 'mips3' maps to -march=r4000, it would assume more memory > latency and a slower integer divider then -march=r4600. I don't really have an issue with that since I see it as a temporary solution until gcc and binutils know about Loongson 2 specifics. Given the bit I know about the Loognson 2 processor architecture I would not expect a significant performance boost from trying different values for -march with current toolchains. Ralf
