Tue, 15 Nov 2011 10:12:37 +0000

Philip Pemberton <philpem@philpem.me.uk>
Tue, 15 Nov 2011 10:12:37 +0000
changeset 109
parent 81

[musashi] Fix handling of bus errors

Patch-Author: Andrew Warkentin <andreww591!gmail>
Patch-MessageID: <4EC200CE.2020304@gmail.com>

I have fixed the first page fault test failure in FreeBee (the page fault test now hangs rather than errors out, because it is trying to read from the hard drive to test DMA page faults).

There were actually two bugs (the first bug was masking the second one).

First, the ancient version of Musashi that you used is unable to properly resume from bus errors that happen in the middle of certain instructions (some instructions are fetched in stages, with the PC being advanced to each part of the instruction, so basically what happens is the CPU core attempts to read the memory location referenced by the first operand, the bus error occurs, causing the PC to jump to the exception vector, but the faulting instruction is still in the middle of being fetched, so the PC is then advanced past the beginning of the exception handler). I fixed this by delaying the jump to the bus error vector until after the faulting instruction finishes.

The second bug is simpler - you had the UDS and LDS bits in BSR0 inverted (they are supposed to be active low).

philpem@0 1 syntax: glob
philpem@0 2 obj/*.o
philpem@0 3 dep/*.d
philpem@0 4 *~
philpem@0 5 .*.sw?
philpem@0 6 .~lock*
philpem@0 7 .buildnum
philpem@2 8
philpem@5 9 # musashi build artefacts
philpem@5 10 src/musashi/m68kopac.c
philpem@5 11 src/musashi/m68kopdm.c
philpem@5 12 src/musashi/m68kopnz.c
philpem@5 13 src/musashi/m68kops.c
philpem@5 14 src/musashi/m68kops.h
philpem@5 15 dep/musashi/*.d
philpem@5 16 obj/musashi/*.o
philpem@5 17 obj/musashi/m68kmake
philpem@5 18
philpem@5 19 # version header
philpem@5 20 src/version.h
philpem@5 21
philpem@5 22 # final executable binary
philpem@15 23 freebee
philpem@5 24 3b1emu
philpem@5 25
philpem@2 26 # ignore ROMs and techref
philpem@2 27 roms
philpem@2 28 TRM
philpem@58 29 misc
philpem@81 30 discs