As far as I can tell, the C18 compiler automatically takes care of the=20
two different context saving methods for WREG, BSR and STATUS, depending=20
on whether the interrupt priority is high (i.e. use shadow regs & fast=20
return) or low (i.e. use stack). Great!

Since ISRs use a temporary data section kept separate from normal C=20
functions, does this create any issues with ISRs calling functions=20
elsewhere in program memory? The C18 Compiler User's Guide=20
(DS51288J-page 28) says the following, but I can't conclude much from it:

"...

Interrupt service routines use a temporary data section that is distinct=20
from that used
by normal C functions. Any temporary data required during the evaluation of
expressions in the interrupt service routine is allocated in this=20
section and is not
overlaid with the temporary locations of other functions, including=20
other interrupt
functions. The interrupt pragmas allow the interrupt temporary data=20
section to be
named. If this section is not named, the compiler temporary variables=20
are created in a
udata section named fname_tmp. For example:
void foo(void);
....
#pragma interrupt foo
void foo(void)
{
/* perform interrupt function here */
}
The compiler temporary variables for interrupt service routine foo will=20
be placed in the
udata section foo_tmp.

...."

In other words, do I have to name or move this ISR temporary area=20
somehow to enable 'normal' execution of arbitrary functions?

Thoughts welcome,
Matt.
--=20
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