Thread (22 messages) 22 messages, 6 authors, 2003-08-19

Re: GCCFLAGS for gcc 3.3.x (-march and _MIPS_ISA)

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
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