Need to actually futz with bank size so it always presents 4 banks on board, unfortunately this leaves the impossible to implement in 4 banks 192k configuration, but it was actually *possible* hardware wise, even if it didn't work due to BIOS bugs.
According to documentation obtained here:
https://www.win3x.org/uh19/public/motherboard/manual/30218.pdf
The ASUS ISA-386C in addition to supporting 32MB onboard, supports an additional 32MB through a proprietary RAM card using an extended ISA connector marked "S1" on the board.
I have no idea on implementation details of this, but the manual seems to imply it just ends up mapped directly into RAM banks 2 and 3. So I'm not sure if raising the RAM limit here is the correct fix, but... yeah. Up to y'all. I won't be offended if you reject this PR out of hand :)
This is a portable computer based around 80C86 processor and Chips &
Technologies chip set. It features a 640x200 monochromatic LCD display,
and up to two 720k 3.25" floppy drives.
It can optionally contain a hard drive controller along with 20M 3.25" MFM
hard drive in place of one floppy drives, which is not emulated yet.
Also not emulated is the expanded memory over 640K.
At least two versions of BIOS have been seen in the wild -- one from
89/09/04 another from 09/12/20.
The MD5 checksums of the ROM images (a pair of chips for each BIOS versions
and a character ROM) are as follows:
SHA1(ce39ab220de25bbd824dbd5c7411c88f3a8d7430) =
roms/machines/v86p/INTEL8086AWD_BIOS_S3.1_V86P_090489_Even.rom
SHA1(9b374cf5aa48186577293c3a83250cdc1aed7c9a) =
roms/machines/v86p/INTEL8086AWD_BIOS_S3.1_V86P_090489_Odd.rom
SHA1(57015c8b85aecb10890d4ddd4a0d133e1ba4ca49) =
roms/machines/v86p/INTEL8086AWD_BIOS_S3.1_V86P_122089_Even.rom
SHA1(1d3217e9fde7410167cd462ad82b360bf546b9d0) =
roms/machines/v86p/INTEL8086AWD_BIOS_S3.1_V86P_122089_Odd.rom
SHA1(59ff86fcfea479b02075c32da12c6c1579d71df5) =
roms/machines/v86p/v86pfont.rom
