Re: [PATCH, ARM] Add -mcpu=cortex-m4f

[Matthew Gretton-Dann <matthew dot gretton-dann at arm dot com>]

On Mon, 2010-09-13 at 23:43 +0800, Jie Zhang wrote:
> On 09/13/2010 11:34 PM, Matthew Gretton-Dann wrote:
> > Jie,
> >
> > On Sat, 2010-09-11 at 03:13 +0800, Jie Zhang wrote:
> >> This patch adds -mcpu=cortex-m4f to GAS. It also documents
> >> -mcpu=cortex-m4, which is missing. OK?
> >
> > Despite what some documents say there is no such processor as
> > Cortex-M4F.  They are all Cortex-M4 with or without an FPU.  This is
> > similar to the Cortex-A8/A9 naming schemes.
> >
> In "Cortex -M4 Technical Reference Manual" (Revision r0p1), page 1-2
> 
> [quote]
> The Cortex-M4 processor is a low-power processor that features low gate 
> count, low interrupt latency, and low-cost debug. The Cortex-M4F is a 
> processor with the same capability as the Cortex-M4 processor, and 
> includes floating point arithmetic functionality (see Chapter 7
> Floating Point Unit). Both processors are intended for deeply embedded 
> applications that require fast interrupt response features.
> [/quote]

We have an erratum for that :-)

As I said above, despite what some of the documents say, I am reliably
informed that there is no Cortex-M4F CPU.  The CPU is Cortex-M4 with or
without FP extensions.

Thanks,

Matt

-- 
Matthew Gretton-Dann
Principal Engineer - PDSW Tools
ARM Ltd