[ECOS] Diff between VSR and Exception

Nick Garnett nickg@ecoscentric.com
Fri Nov 21 11:08:00 GMT 2003


Ottawa Guy <ottawaguy81@yahoo.com> writes:

> Hi,
> ECOS has three types of vectors 
> 
> CYGNUM_HAL_VSR_XX
> CYGNUM_HAL_INTERRUPT
> CYGNUM_HAL_EXCEPTION 
> 
> CYGNUM_HAL_INTERRUPT is used for external interrupt.
> However CYGNUM_HAL_VSR_XX,CYGNUM_HAL_EXCEPTION  sounds
> like  processor interrupt. Eg MemMiss alignment, div
> by zeor, etc.
> 
> What are the diff between CYGNUM_HAL_VSR_XX,
> CYGNUM_HAL_EXCEPTION vectors. 

The CYGNUM_HAL_EXCEPTION_XXX names are standard names for various
types of exception. The CYGNUM_HAL_VSR_XX names are what the hardware
actually provides. In hal_intr.h or somewhere similar the
CYGNUM_HAL_EXCEPTION_XXX names are mapped on to the CYGNUM_HAL_VSR_XX
names. Then, if a portable piece of code wants to known whether a
given kind of exception is available it can test the
CYGNUM_HAL_EXCEPTION_XXX definition and use it to reference the
exception if it needs to. See the kernel except1 and kexcept1 tests
for an example.

-- 
Nick Garnett                    eCos Kernel Architect
http://www.ecoscentric.com      The eCos and RedBoot experts


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