Thinkpad T41 compatibility

crazii / SBEMU

legacy sound blaster emulation for DOS

GNU General Public License v2.0

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Thinkpad T41 compatibility #95

Closed Torinde closed 7 months ago

Torinde commented 8 months ago

The following issue was resolved at VSBHDA:

https://github.com/Baron-von-Riedesel/VSBHDA/issues/4#issuecomment-1934590211

Well, I checked the port 0x20 trapping with DEBUG. The I/O simulation for IN and OUT did modify parts of register AX that should have remained constant - both with QPIEMU.DLL and Qemm. So rmtrap.asm had a bug and has been fixed.

I don't know if SBEMU already handles that.

crazii commented 7 months ago

SBEMU should not have that problem, rmtrap.asm is an modified code for VSBHDA. SBEMU doesn't have it. I didn't read the code but VSBHDA does rm trap in a different way I guess.

crazii commented 7 months ago

SBEMU traps rm ports and goes to PM, I guess VSBHDA optimized out the mode switches by handling the trap in rm? That's why it permanently traps rm PIC ports while SBEMU only temporarily trap PIC for rm programs when raising the virtual SB IRQ to avoid unnecessary mode switches and thus improve performance.