Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Thu, 7 Jul 2011 11:10:01 -0500

Hi Dirk,

On 2011-07-07 Dirk Zimoch wrote:
> 
> Can anyone tell me the differences between ppc603 and ppc604 from the
> software point of view? Are there instructions that one type supports
> and the other doesn't?

I think the main differences are some of the special-purpose registers (SPRs) 
that are accessible at Supervisor level, used for obscure things like 
performance monitoring and power or thermal management.  The basic instruction 
set is common to all 32-bit PowerPC CPUs, so it's only if you're doing BSP-
level things like turning Caches on/off or programming the MMU that the 
differences really matter.  The SPRs are accessed using the mtspr and mfspr 
instructions.  There are also a few optional and implementation-specific 
instructions that the two Microprocessor Technical Summary documents I found 
online mention briefly.

I added two new target architectures to Base 3.14.12.1, vxWorks-ppc32 and 
vxWorks-ppc32sf (soft-float) so sites don't have to compile the code more than 
is really necessary.  Here at APS we're using them as part of our switch to 
vxWorks 6.8, so our engineers can convert IOCs to 3.14.12.1 using the old 
targets on vxWorks 5.5.2, but then switch to 6.8 using the same release of 
Base with the new targets so we can separate out any issues due to the OS-
version.

HTH,

- Andrew
-- 
Optimization is the process of taking something that works and
replacing it with something that almost works, but costs less.
-- Roger Needham

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System