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Re: xscale-elf-gcc

> Hi,
> When I use the march=armv4t option with the xscale-elf-gcc compiler,
> what pipeline does it target? Does it use armv4t compliant instructions
> but still target the xscale pipeline? The reason I ask is because I
> notice that the compiler chooses to predicate branches even when the sequences
> are long (branches would incur 1 stall but long sequences of predicated code
> would result in no-ops).

The honest answer is that I'm not sure without completely 
reverse-engineering the relevant part of the code.  However, I suspect 
that the if-conversion pass is sometimes getting too enthusiastic -- I've 
occasionally seen sequences way longer than the 4+4 that I would normally 

> When I specify mcpu=strongarm and march=armv4 the compiler complains about
> a conflict. Isn't the strongarm compliant with armv4?

Use -mcpu on its own, or -march=<arch> and -mtune=<processor> together.

> Another question: which is the first arm processor to support thumb instructions?

ARM7TDMI (architecture armv4t).


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