This change adds a new "Step Over" button, which is enabled
when a "JSR" (Jump to Subroutine) instruction is encountered
while stepping through execution one instruction at a time.
Pressing "Step Over" will continue running instructions until a
corresponding "RTS" (Return from Subroutine) is encountered.
While stepping over a subroutine, the call stack depth is tracked
in an attempt to halt only when the *correct* RTS is encountered.
In other words, it should skip over other subroutines nested
inside the call you want to step over:
```
JSR A # Step over here...
...
JSR B
...
RTS # Returns from 'B', doesn't halt
...
RTS # Returns from 'A', halts after return
```
Implements feature request #18.
This change introduces a new command line flag, '-b', that cause the
simulator to halt on the `BRK` instruction. By default, however, the
simulator will no longer halt on `BRK`.
As before, this behavior can be toggled in the preferences at run-time.
- IR field in status panel now correctly displays the next instruction
to be executed, instead of the instruction that was just executed.
- Switched from built-in Java util logger to Logback
- Updated all copyright strings to 2016
Introduces several changes requested by Mario Keller. The simulator now has a variable step count that can be selected by a drop-down box on the main window. This change also displays ASCII characters in the Memory window.
The simulator now passes Klaus Dormann's 6502 Functional Test suite for
the first time.
Bug Fixes:
- PHP was not correctly setting the Break bit on the stack copy of the
processor status, so subsequent PLA's would not set the Break status
flag.
- The CPU had swapped NMI and IRQ reset vectors, so RTI was failing.
- BRK was pushing PC + 2 onto the stack, instead of PC + 1
- (Zero Page,X) addressing mode did not correctly wrap on zero page
boundaries.
- The instruction table used for disassembly had addressing modes
of LDA $B9 and $BD reversed. This did not affect behavior, only
disassembly of these instructions.
Other:
- Updated copyright date for 2013.
- Started migrating old JUnit 3 style tests to JUnit 4 annotations.
- The UI layout has changed, and will likely change again in the future.
- Symon can now re-load ROM images from the File menu, under "Load ROM..."
- Font size can be changed under the "View" menu
- Added ability to change inner border width of console window.
- Fixed a nasty bug that prevented key press handling.
- Reset now clears the accumulator and index registers.
Seth Morabito