Does anybody have NMI Handler code for MIPS R4000 / TX19L ?

Robert Ward
Mon Dec 9 23:02:00 GMT 2002

Hi All

I am hoping someone can help.

I am looking for startup / exception handler code for a TX19L for
handling the NMI.

According to the information I have, the R4000 (and the TX19L) share the
reset vector for the hardware reset, soft reset and nmi events, and the
handler code is required to differentiate between S/W and H/W resets
using the SR bit of the status register, and the NMI and Soft reset are
differentiated using "system level identification", which I assume can
be implemented using a variable in NVRAM.

The CRT0 code that I have examined (from newlib, and a couple of
commercial compilers) makes no checking of the SR bit, and just proceeds
as if the event is a H/W reset.  Has anybody written an exception
handler for this to both differentiate between RESET/Soft RESET and NMI
events ?

Have I missed something (I am fairly new to MIPS development).

Robert Ward



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