Re: ARM EABI port: minimum CPU choice
On Tue, 2006-06-13 at 12:14 +0100, Catalin Marinas wrote:
> On Tue, 2006-06-13 at 10:41 +0100, Phil Blundell wrote:
> > On Mon, 2006-06-12 at 23:54 +0200, Martin Guy wrote:
> > > Is there any reason not to make ldm the default for armv4 and above,
> > > since it seems to win most, among the various options?
> >
> > Two reasons: because it requires the return address to be on the stack
> > (which often requires adding another instruction to get it there)
>
> But isn't LR saved anyway in functions that call other functions?
Yes, it is. Those functions will already return either with LDMIA sp!,
{..., pc} or LDR pc, [sp], #4 depending on whether any other registers
were pushed. Both of those sequences are already interworking-safe on
ARMv5, and will work fine in ARM-state on v4 (but, obviously, with no
interworking).
p.
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