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 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.
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.
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.
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.
Clock reset was not being handled gracefully at all, leading some
diagnostic tests not to pass, or not to pass consistently.
This change will "kick" the system clock whenever the timer divider is
reset, so the new divider is picked up immediately.
