06095: fsa1fm and others: [possible] "Expanded memory" mode fails to free up more RAM

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
06095	Gameplay	Minor	Always	Dec 6, 2015, 02:14	Dec 8, 2015, 18:42

Tester	einstein95	View Status	Public	Platform	MESS (Official Binary)
Assigned To		Resolution	Open	OS	Windows Vista/7/8 (64-bit)
Status [?]	Confirmed			Driver	msx/msx.cpp
Version	0.168	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	06095: fsa1fm and others: [possible] "Expanded memory" mode fails to free up more RAM
Description	As the documentation on what this mode is called is sparse, I will further refer to it as an "expanded memory mode". The game Final Fantasy requires more free memory and an error screen will appear if this is not so. The error screen says to hold Ctrl while booting the machine and in this mode boots and runs fine. From the "MSX2 Technical Handbook": "On MSX, even when disks are mounted, they can be cut off by resetting while pressing the SHIFT key. When only one drive is mounted, the normal invocation causes the work area for two drives to be allocated (mainly for 2 drive simulator): in such a case, invoking the works area for only one drive is possible by resetting while pressing the CTRL key. If these steps are taken, more user's area can be allocated." While this works on some MSX2 systems that are defined in msx.cpp as DISK1, DISK2, DISK5 or DISK6 (using the WD2793, MB8877A or Microsol floppy controllers), it does not work on systems defined as DISK3 or DISK4. The only systems defined as DISK4 are Turbo-R machines and are marked as "not working".
Steps To Reproduce	Launch any of the DISK3 systems, such as fsa1fm with ffant in the floppy drive and hold Ctrl during boot. A screen will appear with the text "Say DOS Version 1.A0 for MSX series" and "OK!". In the error log, msx_slot_disk3_device will attempt to do a lot of unmapped write writing. In DISK1, DISK2, DISK5 or DISK6 systems, such as fs5000, the game boots normally with Ctrl held during boot.
Additional Information	I'm not sure if this is an error in msx.cpp or if it's simply due to the programmer of the disk ROM failing to take this mode into account. Some related sets to test: ax370, kmc5000, fsa1f, expertdx, fsa1fx, fsa1wsx, fsa1wx, fsa1wxa, phc70fd, phc70fd2
Github Commit

Flags	Possible
Regression Version
Affected Sets / Systems	fsa1fm and others

Attached Files

No.12231 Tafoid Administrator Dec 8, 2015, 18:42	I can duplicate the behavior "mame fsa1fm ffant" using the CTRL while booting and noting the -log output. Not sure if the issue, like you said, is with driver or actual behavior with that model and disk hardware.