This commit introduces dozens of changes to make the 3B2-700 simulator
fully functional and ready for wider use. In addition to 3B2-700
availability, this commit includes a tremendous amount of refactoring
of the 3B2-400 and common code to make the project structure easier to
maintain and reason about.
One final important change: ROM files are no longer included in the
source code. 3B2 ROM images must be obtained separately and loaded
into the simulator before boot.
Changes:
- The 3b2 target has been aliased to 3b2-400
- The formerly named 3b2-600 project has become 3b2-700
- SCSI QIC tape support has been added to sim_scsi.c
- Header files have been reworked to reduce complexity of includes
- Common code has been consolidated
- Timer code has been unified
This commit fixes an issue that caused floppy diagnostics to fail if
the floppy drive unit was not attached. The 3B2 floppy controller has
a "force interrupt" command that should run whether or not the floppy
unit is attached to an image.
- This change introduces a full refactor of the interrupt subsystem
for the system board (SBD) and the I/O bus (CIO). Interrupt decode
should now be significantly faster, and not require an expensive
calculation on every step.
- The TIMER device has been split into Rev 2 and Rev 3
implementations.
- The optional 3B2/400 Debug Monitor ROMs can now be booted by passing
the "DEMON" argument to the 3B2/400 simulator BOOT command. Any
of the following will cause the Debug Monitor ROM to be booted
instead of the standard 3B2/400 ROM:
sim> BOOT DEMON
sim> BOOT CPU DEMON
sim> BOOT DEMON CPU
This change signficantly improves header hygiene in the 3B2 project by
moving global symbols out of 3b2_defs.h and into the appropriate
individual module header files.
Each compilation unit now includes:
- its appropriate matching .h file
- any other .h files necessary for linting and compilation
Each header file in turn includes 3b2_defs.h, which contains truly
global symbols, and which pulls in sim_defs.h and exports global
devices.
The Rev 3 firmware does not check floppy controller status before
commanding a sector read, which can lead to calling sim_disk_rdsect()
on a detached unit. With this checkin, the simulator will no longer
attempt a read or write if the floppy unit is not attached.
This change introduces initial support for the AT&T 3B2 Rev 3 platform, based
around the WE32200 CPU with up to 64MB of RAM and SCSI disk and tape support.
This simulator is experimental and not yet supported. It will not be built by
default, but can be built with:
make 3b2-600
Or by using the 3B2-600 Windows Visual Studio project.
Floppy disk images are potentially used as a medium of data exchange
between some hosts and simulators and the disk information can confuse
this process.
As discussed in #847
Refactor in preparation for the addition of a Rev 3 simulator for the
3B2/1000 system.
This change also includes a full cleanup of the rat's-nest of includes
and externs that plagued the 3B2 simulator and made it difficult to
understand and maintain. Headers are now required in the following
order:
compilation unit -> "3b2_defs.h" -> {... dependencies ...}
Finally, HELP has been added to the CPU device.
- Formerly, the floppy controller buffered an entire diskette image
in memory using the unit buffer, and flushed it out on detach or
shutdown. This worked well enough, but it's better to have the
device use the SIMH disk sector read and write routines and
behave like a true disk.
- Read Only (Write Protect) logic has also been enabled in the
floppy controller, allowing users to mount images that do not
have write permissions.
- The IF (Integrated Floppy) and ID (Integrated Disk)
device names were poorly chosen. They conflict with built-in
scp commands and mess up the help system. This commit
changes them to IFLOPPY and IDISK, respectively.
NOTE!! THIS IS A BREAKING CONFIG CHANGE!!
This change cleans up warnings issued when compiled with
-Wall.
- Removed unused functions and variables.
- Moved static declarations out of headers and into source files
- Added braces around initialization where suggested.
Adds a skeleton framework for CIO ("Common I/O") feature cards. The
first feature card to be implemented will be the "PORTS" serial MUX.
Part of this support involved reworking IRQ handling in the CPU. It
now respects both IRQ Vector and IPL.
This change also removes all 'assert(0)' calls from the simulator and
replaces them with generic "Simulator Error" halts. These should only
happen if there's a genuine logic error lurking somewhere.
This change is a major refactor of how DMA and the DUART interact.
DMA implementation can now be overridden by individual devices that
require DMA. Disk and Floppy both continue to use a generic DMA
implementation, but the DUART code replaces the generic DMA with its
own implementation that correctly rate-limits TX. Among other things,
this allows the simulator to work correctly with real serial
terminals. This functionality has been tested on an AT&T 5620 "Blit"
terminal, which can run the 'layers' windowing software from the
simulator.
