Viewing Issue Advanced Details
|ID||Category [?]||Severity [?]||Reproducibility||Date Submitted||Last Update|
|08464||Core||Critical (emulation)||Always||Oct 23, 2022, 04:47||Oct 25, 2022, 14:43|
|Tester||pnp2084||View Status||Public||Platform||MAME (Official Binary)|
|Assigned To||pnp2084||Resolution||Fixed||OS||Windows 10/11 (64-bit)|
|Version||0.248||Fixed in Version||0.250||Build||64-bit|
|Fixed in Git Commit||99b3304||Github Pull Request #||#10464|
|Summary||08464: trs80l2: Game boot loader fails due to overlapping FDC commands|
The two attached graphic adventures have a custom boot loader which does not work on the TRS-80 Model I emulation. The games fail to start.
(It does work for the Model 3 emulation but that different boot code)
|Steps To Reproduce||
Try to boot any of the two games. DISK ERROR will appear instead of a splash screen.
mame trs80l2 -flop1 spook_house.mfiOr:
mame trs80l2 -flop1 sledge.mfi
The ROM boot loader immediately jumps to $4200 but the read sector command is not finished.
The boot sector code issues a step command. The FDC emulation accepts the command (with a delay) and sets the busy bit. But when the previous read command finishes, BSY is cleared before the delayed step command starts.
As a result, the boot code sees the STEP command finish, putting the boot code in an inconsistent state.
|Affected Sets / Systems||trs80l2|
graphic_adventure.zip (112,253 bytes) Oct 23, 2022, 04:47 Uploaded by pnp2084
MFI disk images for Sledge of Rahmul and Spook House
|There are no relationship linked to this issue.|
Oct 23, 2022, 05:27
I've created a pull request with a proposed fix: