08839: ngp, ngpc: debugger misbehaves

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
08839	Debugger	Minor	Always	Mar 21, 2024, 12:07	Mar 24, 2024, 01:40

Tester	Robbbert	View Status	Public	Platform	MAME (Self-compiled)
Assigned To	hap	Resolution	Fixed	OS	Windows 10/11 (64-bit)
Status [?]	Resolved			Driver	snk/ngp.cpp
Version	0.263	Fixed in Version	0.265	Build	64-bit
		Fixed in Git Commit	4113b55	Github Pull Request #

Summary	08839: ngp, ngpc: debugger misbehaves
Description	After using the do pc command, the debugger steps a wrong number of bytes causing the system to misbehave. CPU = TMP95C061
Steps To Reproduce	1. Start the system: mame ngp -d 2. You are at FF1800. Step 3 times. Now you are at FF1809. 3. Type in: pc=FF1807 4. This should return you to the previous line. Step once. This should bring you back to FF1809. 5. However we are now at FF180A, and the disassembly has changed. This problem can occur anywhere with this CPU, and sometimes proceeding can make the system freeze. I tried at another address, and instead of stepping 3 bytes, sometimes it was 1 or 2. Unfortunately this makes the debugger almost useless.
Additional Information
Github Commit

Flags
Regression Version
Affected Sets / Systems	ngp, ngpc

Attached Files