> From: Fritz Mueller > I've had a bit of time in front of the machine to repro this and take a > look. What I actually see is:
> R0 177770 > R1 0 > R2 0 > R3 0 > R4 0 > R5 34 > R6 141774 > PC 000254 Argh. (Very red face!) I worked out the trap stack layout by looking at m40.s and trap.c, and totally forgot about the return PC (that's the 0444) from the call to trap(): 0001740 000013 141756 022050 000013 000000 000000 000000 000034 0001760 000444 000031 177760 000000 030351 177770 010210 170010 I clearly should have looked at core(V) in the V6 manual! The R6 you have recorded is correct for just after the trap; that's the kernel mode SP, which points to the top of the kernel stack, in segment 6 (in the swappable per-process kernel area, which runs from 140000-1776). So there is no R5 mystery, I was just confused. Back to the other two! Noel