3b1emu / changelog

Improve floppy disc support

• Sat, 17 Nov 2012 19:13:08 +0000
• by Philip Pemberton <philpem@philpem.me.uk> [Sat, 17 Nov 2012 19:13:08 +0000] rev 111
• Improve floppy disc support
  
  Patch-Author: Andrew Warkentin <andreww591!gmail>
  Patch-Message-ID: <50A772FC.8020009@gmail.com>

[musashi] fix stackframe type for bus errors

• Thu, 08 Dec 2011 23:44:19 +0000
• by Philip Pemberton <philpem@philpem.me.uk> [Thu, 08 Dec 2011 23:44:19 +0000] rev 110
• [musashi] fix stackframe type for bus errors
  
  Bus errors incorrectly pushed a Type 0000 stackframe, when they should have pushed a Type 1000 (Type $8) stackframe.
  Also, type 1000 frames were not handled for 68010 CPUs. They are now, but code must later be added to handle them for 68020s. FIXME!
  
  Reported-By: Armin Diehl <ad ardiehl.de>

[musashi] Fix handling of bus errors

• Tue, 15 Nov 2011 10:12:37 +0000
• by Philip Pemberton <philpem@philpem.me.uk> [Tue, 15 Nov 2011 10:12:37 +0000] rev 109
• [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).

Fix BSR0 UDS/LDS bit polarity

• Tue, 15 Nov 2011 09:30:57 +0000
• by Philip Pemberton <philpem@philpem.me.uk> [Tue, 15 Nov 2011 09:30:57 +0000] rev 108
• Fix BSR0 UDS/LDS bit polarity
  
  Patch-Author: Andrew Warkentin <andreww591!gmail>
  Patch-MessageID: <4EC200CE.2020304@gmail.com>
  
  ... "The second bug is simpler - you had the UDS and LDS bits in BSR0 inverted (they are supposed to be active low)."