Wrong palette is used in 4bpp packed pixel modes

[MrMadguy64]

Describe the bug

If I try to change EGA palette in 4bpp packed pixel mode via Int 10h 1002h - following problem happens:

Testing shows, that palette is set correctly in other modes.

Steps to reproduce the behaviour

1. Set any 4bpp packed pixel mode
2. Try to change palette via Int 10h 1002h

Expected behavior

What operating system(s) this bug have occurred on?

Windows

What version(s) of DOSBox-X have this bug?

Latest

Used configuration

No response

Output log

No response

Additional information

No response

Have you checked that no similar bug report(s) exist?

• I have searched and didn't find any similar bug report.

Code of Conduct & Contributing Guidelines

• I agree to follow the code of conduct and the contributing guidelines.

[MrMadguy64]

Problem on second screenshot was my fault - it's fixed now.

[joncampbell123]

This is 320x200 or 640x200 16-color mode, correct?

The palette works differently in 200-line modes vs 350-line modes. It has to do with how the monitor interprets the 6-bit output pins where 200-line is RGBI and 350-line is the RRGGBB 64 possible colors.

http://www.ctyme.com/intr/rb-0116.htm

https://en.wikipedia.org/wiki/Enhanced_Graphics_Adapter

[joncampbell123]

This might also help: https://cosmodoc.org/topics/ega-functions/#SetPaletteRegister