Fabian Cenedese writes:
> At 14:33 07.12.2006 +0100, Fabian Cenedese wrote:
> >Hi
> >
> >Is there a flag to tell gcc NOT to use float assembler commands
> >for 64bit data? We have problems that the generated code contains
> >float commands while the target (partially) has no float support.
> >
> >To make it clear: This is not about the soft-float library which would
> >emulate float commands. We don't want gcc to even generate
> >those unless it really is about float operations.
> >
> >Here's one example (for PPC603), but there also are others:
> >
> >inline uint64 GetSystemTicks()
> >{
> > union {
> > uint64 s;
> > struct {
> > uint32 high;
> > uint32 low;
> > } m;
> > } result;
> >
> > uint32 tmp=0;
> > asm volatile (
> > "mftbu %0" "\n\t"
> > "mftb %1" "\n\t"
> > "mftbu %2" "\n\t"
> > "cmpw %3,%4" "\n\t"
> > "beq 0f" "\n\t"
> > "mftbu %0" "\n\t"
> > "mftb %1" "\n\t"
> > "0:"
> > : "=r" (result.m.high), "=r" (result.m.low), "=r" (tmp)
> > : "0" (result.m.high), "2" (tmp));
> >
> > return result.s;
> >}
> >
> >...(snip)...
> > mr 0,10 # tmp120,
> > stw 0,8(31) # result.m.high, tmp120
> > stw 9,12(31) # result.m.low, tmp121
> > stw 11,16(31) # tmp, tmp122
> >-> lfd 0,8(31) # result.s, result.s
> >-> stfd 0,24(31) #, result.s
> > lwz 9,24(31) #, <result>
> > lwz 10,28(31) #, <result>
> > mr 3,9 # <result>, <result>
> > mr 4,10 # <result>, <result>
> > lwz 11,0(1) #,
> > lwz 31,-4(11) #,
> > mr 1,11 #,
> > blr #
> >
> >The float commands are simply used for moving 64 bit of data around.
> >That may be faster than 2x32 but not working here. I'm interested in
> >workarounds for various gcc versions (2.95, 3.4, 4.x).
>
> Doesn't anybody know a way around this? Or has the same problem?
I guess we're having difficulty understanding why -msoft-float is not
appropriate for you. It seems to me obviously the right thing to do
with a target (partially) without float support.
Andrew.
