LC-3 Simulator Bugs
This document summarizes the known bugs in the LC-3 simulator. Please
send detailed bug reports to cse240 at seas.upenn.edu.
LC-3 status label does not update correctly to "halted" every time the machine halts, under Java 1.5 (noted by zarko).
The immediate offset for LDR instructions is missing its # sign (noted by zarko).
||Fixed in version
||The Keyboard Data Register is not cleared on a system reset.
||The Display Status Register is never "ready" when running in GUI mode.
||Using the 'input' command silently disables the Text I/O console device, and the device cannot be re-enabled without closing and re-opening the simulator.
||The 'check' command doesn't work correctly when checking memory locations for negative decimal values.
||Script commands after a 'continue' sometimes get queued without being processed; you have to enter another command to get them to execute.
||Memory labels from previously loaded programs persist when a new program is loaded to the same address range.
- Fixed KBDR-not-cleared-on-system-reset bug.
- Fixed DSR-never-ready bug.
- Added recursive scripting support. Whee!
- Fixed bug with 'check' command and negative decimal values.
- The 'reset' command now re-enables the Text I/O Console in the
GUI. Additionally, the Console changes colors to indicate whether it
has focus or is disabled.
- Added the 'dump' command for dumping memory ranges to a text
file. See the LC-3 manual for
information on this and other new features.
- Added check pass/failure counting, via the 'check count' and
'check reset' commands.
- The LC-3 timer device can now be controlled manually: a "."
(period) read from an input file or from the Text I/O Console will
generate a "tick." Set the timer interval to 1 to enable this manual
- Fixed post-continue script commands bug.
- 'set' and 'check' commands now both accept memory ranges are
arguments, so "set x3000 x300a 15" will set 11 addresses, starting
at x3000, to have the value 15. "check x3000 x300a 15" will verify
that those 11 addresses each indeed contain the value 15.
- Prefixing a '@' character to a command prevents it from being
added to the command history. This is done automatically for
commands in script files, so they no longer "pollute" the
- Fixed memory label bug.
- Added 'ld' alias for 'load' command
E CHRISTOPHER LEWIS
Last modified: Sat Nov 12 10:50:50 EDT 2005