Re: GCCFLAGS for gcc 3.3.x (-march and _MIPS_ISA)
From: Thiemo Seufer <hidden>
Date: 2003-08-19 06:41:28
From: Thiemo Seufer <hidden>
Date: 2003-08-19 06:41:28
Ralf Baechle wrote:
On Tue, Aug 12, 2003 at 08:51:18AM +0200, Thiemo Seufer wrote:quoted
quoted
GCCFLAGS += -mabi=32 -march=mips2 -mtune=r4600 -Wa,--trap (or GCCFLAGS += $(call check_gcc, -mcpu=r4600 -mips2, -mabi=32 -march=mips2 -mtune=r4600) -Wa,--trap) Isn't it?-march=mips2 is an alias for -march=r6000, I don't think that's a good choice.Why? MIPSII / MIPS32 are the highest ISAs supported for building 32-bit kernels so that makes sense.
Because you get only MIPS II instructions then. This doesn't matter much for R4600, but the improvements of later ISAs won't be used. -mabi=32 -march=r4600 works for 32bit kernels with newer toolchains, there's no need to use -mtune separately. Thiemo