05985: Z80 CPU core can't handle many IX/IY (0xdd/0xfd) instruction prefixes in a row

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
05985	Crash/Freeze	Critical (emulator)	Always	Jul 11, 2015, 10:45	Apr 20, 2018, 06:16

Tester	MetalliC	View Status	Public	Platform
Assigned To		Resolution	Fixed	OS
Status [?]	Resolved			Driver
Version	0.163	Fixed in Version		Build
		Fixed in Git Commit		Github Pull Request #

Summary	05985: Z80 CPU core can't handle many IX/IY (0xdd/0xfd) instruction prefixes in a row
Description	code in provided example software do follwing - fills big RAM area with 0xFD and jump there as result I see in error log a lot of "Z80 ':maincpu' ill. opcode $fd $fd" messages and then emulator exits, silently, without printing any callstack messages. I think stack overflow happens.
Steps To Reproduce	- unpack provided floppy image to MAME folder - run "mame pentagon -flop1 fuckemul.trd" - select TR-DOS (cursor up, enter) - RUN (r, enter) shortly emulator silently closes for me, other user reported appcrash message
Additional Information
Github Commit

Flags
Regression Version
Affected Sets / Systems

Attached Files	fuckemul.zip (1,710 bytes) Jul 11, 2015, 10:45 Uploaded by MetalliC

No.11867 Tafoid Administrator Jul 11, 2015, 17:56 edited on: Jul 11, 2015, 17:59	Do we have any confirmed way to run this on real hardware and have it be something that we can actually see operate correctly - are there any visual clues built into the program that will let us know it works or doesn't other than exception crashing? That said, I do get an exception, but no stack: Exception at EIP=0000000002CC2966 (z80_device::illegal_1()+0x00a6): STACK OVERFLOW
No.14938 Robbbert Senior Tester Apr 10, 2018, 06:56 edited on: Apr 10, 2018, 07:00	This doesn't seem to be an issue any more. No crash for me. Also, I tried in super80m setting 32k of ram to FD and running it - no crash. To test in super80m start it and do the following steps: (press enter at the end of each line) F 0 7FFF FD E 8001 (this gives a new prompt) type in C3 4 C0 then a period. G0 You'll get a prompt on a new line, indicating success.
No.14957 Robbbert Senior Tester Apr 18, 2018, 04:30	No response, so let's close it. Don't know who fixed it, or when.
No.14962 Tafoid Administrator Apr 18, 2018, 19:44	Please do not assign current GIT as the "fixed" when you are not sure when something is fixed, just leave blank and resolve.
No.14968 M.A.S.H. Senior Tester Apr 19, 2018, 23:22	I don't think this bug was fixed! I still get the error messages [:maincpu] Z80 ill. opcode $fd $fd... Using mame pentagon -flop1 fuckemul.trd -log
No.14970 Robbbert Senior Tester Apr 20, 2018, 06:16	The bug report was because it caused an unexpected exit, which has been fixed. The log message can be ignored.