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

[Atsushi Nemoto <anemo@mba.ocn.ne.jp>]

I'm trying to compile kernel with gcc 3.3.1 and binutils 2.14.  I
found this report on this ML:

>>>>> On Tue, 13 May 2003 13:33:16 +0200, Guido Guenther <agx@sigxcpu.org> said:
Guido> Just for completeness: I had to use:
Guido>  GCCFLAGS += -mabi=32 -march=r4600 -mtune=r4600 -Wa,--trap
Guido> to make gcc-3.3 happy (note the 32 instead of o32). gcc-3.2
Guido> doesn't seem to handle these options correctly at all.

It can compile the kernel, but handle_adel_int (and handle_ades_int)
contain wrong codes.

8002630c <handle_adel_int> 40284000     dmfc0   t0,$8
80026310 <handle_adel_int+0x4> 00000000         nop
80026314 <handle_adel_int+0x8> ffa800a4         sd      t0,164(sp)

The source code for this instructions are:

#define __BUILD_clear_ade(exception)                                    \
                .set    reorder;                                        \
                MFC0    t0,CP0_BADVADDR;                                \
                .set    noreorder;                                      \
                REG_S   t0,PT_BVADDR(sp);                               \
                KMODE

The macro MFC0 and REG_S are defined asm.h and depend on _MIPS_ISA.

#if (_MIPS_ISA == _MIPS_ISA_MIPS1) || (_MIPS_ISA == _MIPS_ISA_MIPS2) || \
    (_MIPS_ISA == _MIPS_ISA_MIPS32)
#define MFC0            mfc0
#define MTC0            mtc0
#endif
#if (_MIPS_ISA == _MIPS_ISA_MIPS3) || (_MIPS_ISA == _MIPS_ISA_MIPS4) || \
    (_MIPS_ISA == _MIPS_ISA_MIPS5) || (_MIPS_ISA == _MIPS_ISA_MIPS64)
#define MFC0            dmfc0
#define MTC0            dmtc0
#endif

The option -march=r4600 seems to make gcc 3.3.x choose MIPS_ISA_MIPS3.

So, the right options is:

        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?

---
Atsushi Nemoto