Interrupts preemptive?

In an ISR, software can enable only the interrupts that it would like to interrupt that ISR, and then re-enable the global interrupt mask.  There is an example in the peripheral header files of a full-blown prioritization scheme.  Most users just want to nest one or two interrupts though, so it is easily handled with a few lines of code.

if you have www.ti.com/controlsuite installed

C:\ti\controlSUITE\device_support\f2803x\v122\DSP2803x_examples_ccsv4\sw_prioritized_interrupts

here is the INT section of the Piccolo 1-day Workshop

http://processors.wiki.ti.com/index.php/C2000_Piccolo_One-Day_Workshop_Module_2#Interrupts

3-day workshop has more details

http://processors.wiki.ti.com/index.php/C2000_Piccolo_Multi-Day_Workshop

Chapter 6 of the Teaching ROM is also excellent (and there are examples for all C2000 families)

http://www.ti.com/ww/eu/university/roms.html

So the default behavior is that new interrupts would NOT preempt an ISR in progress?  Including dispatched HWI in DSP-BIOS?