[Patch] Sigma Designs Color 400 video card

Post new patches here!
Post Reply
User avatar
JohnElliott
Posts: 73
Joined: Sun 31 Jan, 2016 7:29 pm

[Patch] Sigma Designs Color 400 video card

Post by JohnElliott » Sat 13 Oct, 2018 1:00 am

The Sigma Designs Color 400 has only one claim to fame that I'm aware of - the only 4-colour driver for Windows 1.0 that I know of was written for it (SIGMA4.DRV).

I implemented it to see what Windows 1.0 looked like in 4 colours:
Image

But I thought I might as well make it up into a proper and reasonably complete patch.

Notes:
  • If your system's BIOS supports video ROM shadowing, disable it before switching to the Sigma card - the card does not work with its ROM shadowed.
  • The card uses non-maskable interrupts to implement hardware-level compatibility with CGA. If you find this leads to instability (for example, the PC hangs when trying to scroll the screen) this can be disabled in the card configuration - this will leave it compatible at the BIOS level only.
Attachments
sigma400.patch
(35.35 KiB) Downloaded 7 times

SA1988
Posts: 227
Joined: Wed 30 Apr, 2014 9:38 am

Re: [Patch] Sigma Designs Color 400 video card

Post by SA1988 » Sat 13 Oct, 2018 11:13 am

Quick question, does this have a bios?

User avatar
JohnElliott
Posts: 73
Joined: Sun 31 Jan, 2016 7:29 pm

Re: [Patch] Sigma Designs Color 400 video card

Post by JohnElliott » Sat 13 Oct, 2018 11:39 am

Quick answer: Yes, it does.

Post Reply