3b1emu / changelog

Fix bit masking logic in 'dead bus' return

• Sat, 17 Nov 2012 22:14:09 +0000
• by Philip Pemberton <philpem@philpem.me.uk> [Sat, 17 Nov 2012 22:14:09 +0000] rev 114
• Fix bit masking logic in 'dead bus' return
  
  In some cases (e.g. 16bit reads) a bad 'idle bus' return may be provided.
  Promote the '1' to unsigned long prior to left-shifting it.

ACCESS_CHECK_RD should return the right number of bits!

• Sat, 17 Nov 2012 21:28:48 +0000
• by Philip Pemberton <philpem@philpem.me.uk> [Sat, 17 Nov 2012 21:28:48 +0000] rev 113
• ACCESS_CHECK_RD should return the right number of bits!
  
  If the ACCESS_CHECK_RD() macro detects a page fault, it always returns a
  32-bit error response ("all bus pins high"). Musashi really doesn't like it
  when we pass in a 32-bit value when it expects a 16-bit one!

add HDD support + fixes

• Sat, 17 Nov 2012 19:18:29 +0000
• by Philip Pemberton <philpem@philpem.me.uk> [Sat, 17 Nov 2012 19:18:29 +0000] rev 112
• add HDD support + fixes
  
  Patch-Author: Andrew Warkentin <andreww591!gmail>
  Patch-Message-ID: <50A772FC.8020009@gmail.com>
  
  I have added floppy write support, full hard disk emulation, and proper handling of DMA page faults to FreeBee. I also fixed the floppy step commands, changed the "force interrupt" floppy command to generate a type 1 status, and changed the DMA address counter to reset to 3fff when a transfer completes (which is what Unix seems to expect - without it, the kernel says that the floppy isn't ready). The floppy, hard disk, and DMA page fault tests all pass. Initializing hard disks and floppies also works (the geometry for both is still fixed by the size of the image, though, and format commands only appear to succeed, but they don't modify the image). Unix still doesn't run, though (it hangs after reading some sectors from the floppy).

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)."

only strobe BUSERR if dma access caused a pagefault, and don't send IRQ0s (musashi auto-clears IRQs)!

• Fri, 04 Mar 2011 02:12:25 +0000
• by Philip Pemberton <philpem@philpem.me.uk> [Fri, 04 Mar 2011 02:12:25 +0000] rev 107
• only strobe BUSERR if dma access caused a pagefault, and don't send IRQ0s (musashi auto-clears IRQs)!