SEVERE Bug in mc68360 _ISR_Handler???

Chris Johns cjohns at
Fri Jul 20 05:49:05 UTC 2001

"Aaron J. Grier" wrote:
> On Tue, Jul 17, 2001 at 05:48:17PM -0500, Joel Sherrill wrote:
> > "m68ks without separate stacks" is all m68k's based on 68000, cpu32,
> > and coldfire cores.
> I've wondered about this...  couldn't the supervisor/user mode switch be
> used on CPU32 to effectively give a separate interrupt stack?

Not sure I see how you would do this without breaking existing code.

The code to switch stacks using software is small, max. 6 instructions
on the way in if a switch is needed, and 4 on the way out. Nesting is
faster. The stability an interrupt stack gives a system is worth the
small overhead. You save memory by not needing to add the worst case
interrupt stack usage to each task.

 Chris Johns, cjohns @

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