kapoor@wuee1.wustl.edu (Sanjay Kapoor) (07/24/90)
Here are a few basic questions regarding the 88000. Q1: How does the 88000 handle interrupts? the sparc architecture helps reduce the overhead for critical interrupts by reserving a register window for trap handling. What about M88000? Q2: What precautions are need to interface to a standard bus eg VME? Is this bus (VME) the best option? Leads/tips/hints etc are welcome Thnks Sanjay Kapoor kapoor@wuee1.wustl.edu
jkenton@pinocchio.encore.com (Jeff Kenton) (07/24/90)
From article <1990Jul24.032416.13340@cec1.wustl.edu>, by kapoor@wuee1.wustl.edu (Sanjay Kapoor): > > Q1: How does the 88000 handle interrupts? the sparc architecture helps > reduce the overhead for critical interrupts by reserving a register window for > trap handling. What about M88000? > The simple answer is that the processor traps to Exception Vector 1 (0 is reset) and the exception handling code does the rest. "The rest" includes saving registers, processing anything in the data or FP pipelines, figuring out which device interrupted (and processing the interrupt), and restoring the interrupted state. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - jeff kenton --- temporarily at jkenton@pinocchio.encore.com --- always at (617) 894-4508 --- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
jat@xavax.com (John Tamplin) (07/26/90)
In article <1990Jul24.032416.13340@cec1.wustl.edu> kapoor@wuee1.wustl.edu (Sanjay Kapoor) writes: >Here are a few basic questions regarding the 88000. > >Q1: How does the 88000 handle interrupts? the sparc architecture helps >reduce the overhead for critical interrupts by reserving a register window for >trap handling. What about M88000? At exception time, the processor state is saved in shadow registers. The exception handler can examine them, correct the problem, and resume execution without any memory accesses if the exception is simple. Running Unix, though, the overhead can be quite large. >Q2: What precautions are need to interface to a standard bus eg VME? Is this >bus (VME) the best option? You really don't want your memory on VME. You should be able to get quite a bit faster throughput with memory sitting directly on the MBus. As far as peripherals, well VME is one of several choices each with tradeoffs. -- John Tamplin Xavax jat@xavax.COM 2104 West Ferry Way ...!uunet!xavax!jat Huntsville, AL 35801