This avoids a potential invalid pointer dereference when formatting
the return value from sim_instr() if it is < SCPE_BASE but greater
than the previously defined static array size.sizeof
Update simh.doc to reflect this generic change.
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.
The WE32100 supports expanded datatypes for its opcodes, allowing an
opcode to override the default size (byte/halfword/word) expected by the
instruction. For example:
CMPH &0x10000,{uword}-8(%fp)
Without the {uword} marker, this instruction would only compare the
lower 2 bytes of -8(%fp) against the lower two bytes of the constant
value 0x10000, since the CMPH instruction compares halfwords. However,
with the {uword} marker, the CMPH instruction promotes the opcode from a
halfword to an unsigned word, sign extending if appropriate.
The CMP{W|H|B} instruction implementation in the 3B2 simulator was
ignoring any expanded type markers on its opcodes when checking whether
to set the "N" (negative) bit in the PSW, leading to a failure in
compiling GCC. This fix causes the instruction to honor the expanded
datatype in this case.
- The previous fix for STRCPY introduced a new bug. STRCPY must always
copy the final NULL terminator of the string, but must NOT increment
the source or destination pointers for the NULL terminator.
- The CTC simulation did not correctly support streaming mode, which
can in some cases request reads that are not on 512-byte block
boundaries.
- To begin to support System V Release 4 UNIX, the NI card (called EMD
under SVR4) needed to support several more CRC codes for pump code.
- A bug in the Square Root implementation could lead to
an infinite loop.
- Incorrect rounding was used when MAU destination register
was single or double word.
- Fix Coverity-discovered issues.
This change adds a small infinite loop program that will be used by
the simulator to establish a reasonable guess at the host's
performance in order to precalibrate the system timer.
- Integer addition of unsigned types could fail to set the
overflow flag, leading to errors in the SVR3 floating point
emulation library that rely on the overflow flag to detect
carry out of high bit on unsigned addition. This change
will correctly set the V flag if the high bit should be
carried out on an add.
This change adds support for the WE32106 Math Acceleration Unit (MAU).
The WE32106 is an IEEE-754 1985 compatible floating point math
acceleration unit that was an optional component on the 3B2/310 and
3B2/400.
The MAU is implemented using software floating point routines. As
always, there may be bugs, but the MAU currently passes extensive
floating point tests with exactly the same results as a real 3B2/400
equipped with a physical MAU, so I hope these are few.
Previously, the NI ethernet device expected to do all
autoconfiguration at attach time. Furthermore, if attaching failed for
some reason (e.g., permission issues on a tap device, etc.) the card
would be left autoconfigured, but in a broken state that could lead to
reading uninitialized memory.
This change fixes those bugs, and allows the device to be attached and
detached more freely. The card is now autoconfigured when it is
enabled. Attaching and detaching are analogous to connecting or
disconnecting an ethernet transceiver from the physical device.
This change enables the simulator to be shut down cleanly via a
soft-power shutdown command. This is implemented in the real 3B2/400
through the sanity timer, which, if it reaches zero, sets a bus timeout
flag in the CSR and issues an interrupt at IPL 15. The operating
system (System V UNIX) treats this as a shutdown request and enters
runlevel 0.
To use this change in a SIMH startup script, for example to implement a
3B2 simulator as a service, one could add these commands:
# [... simulator setup ...]
BOOT
SET TIMER SHUTDOWN
CONTINUE
EXIT
On catching a SIGTERM, SIGINT, or SIGHUP, the simulator would return to
SCP control, set the soft power shutdown flag, and then continue
simulator execution. After the system is cleanly shut down, the
simulator would then exit back to the operating system.
This change also addresses some unused function parameter warnings
issued by GNU Flycheck (not generally used by the build process, but
useful when editing files with Flycheck enabled)
- 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!!
- The DMAC controller "Current Word Count" expects to decrement
beyond 0 to 0xffff. Its initial value should also be 0xffff.
Setting the initial value to 0 introduced a very subtle bug
related to DUART self-test following a soft power reset.
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.
Previously, tmxr_set_line_unit() and tmxr_set_line_output_unit()
were being called in the attach routine. These probably belong
in the reset routine instead.
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.
- Add "SHOW STACK" support to CPU
- An off-by-one error in checking SDT length was fixed.
- not-present co-processor R/W should not set Bus timeout bit
