[Bug 1001468] eCos GNU tools 4.6.2

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--- Comment #41 from Jonathan Larmour <jifl@ecoscentric.com> 2012-03-19 01:50:00 GMT ---
(In reply to comment #40)
> 
> I'll try this. 

Thanks.

> However, please note that despite having double registers
> d0..d15 Cortex-M4F has hardware support only for single precision FP arithmetic
> so single precision view of registers (s0..s31 instead of d0..d15) would be
> more useful for floating point representation of register contents.
> Double
> precision floating point is actually done in software and does not involve
> d0..d15, at least not with GCC.
> Single precision naturally uses s0..s31 VFP
> registers. Below there is a code sample.

Yes I know, but as per comment 37, GDB provides pseudo-regs for the single
precision registers, so you can still see them (if you can't see them after my
patch then I've missed something). It will be alongside the d0..d15 view of the
registers, in line with all other ARM VFP FPUs, and it could be argued that
since http://infocenter.arm.com/help/topic/com.arm.doc.ddi0439b/BEHJADED.html
shows that you can still load and store doubles, it should still be possible to
have some means of viewing them.

Anyway, GDB has no support for any other model for the single precision
registers. Doing anything else would require quite a few GDB changes for
nothing more than cosmetic gain (the removal of the d0..15 part of the view of
registers in 'info all-reg'). Simply put, the behaviour you are looking for is
not yet possible to arrange in GDB at the moment.

Jifl

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