Incorrect 8088 (4,77 MHz) emulation speed in games

[usergithub64]

In games such as Arkanoid, Buck Rogers (Planet of Zoom), Eden Blues, Flightmare, and others, there is an incorrect processor emulation speed of 8088 (4,77 MHz). This is especially noticeable in the game Arkanoid by the speed of music playback in the initial splash screen of the game. To understand how this music should sound (if there is no real PC 8088 (4,77 MHz), in DOSBox ECE or in DOSBox-X you need to set cycles = 240 and run this game.
Here's how the music should sound. (both on a real machine 8088 XT 4.77 MHz and in DOSBox with cycles = 240)
https://youtu.be/_7mouV05qy0

I draw your attention to the fact that the Paratrooper (1982) game in 86Box at 8088 (4,77 MHz) now works correctly! You can hear PC Speaker sounds of flying helicopters and airplanes.

[fuel-pcbox]

DOSBox is heavily inaccurate compared to 86box when it comes to 8088 timings, so of course there are going to be differences. :P

[OBattler]

There are some problems remaning with 808x timings, mostly related to DMA refresh cycles for which currently, a crude approximation is used. Eventually they are going to be made more accurate.

[OBattler]

I'm going to look into this.

[OBattler]

I confirm this and I suspect some 808x instruction (I believe that commit did change a few) is now misbehaving, causing this.

[OBattler]

I just committed a fix for this, it was the DAA instruction that accidentally broke.

[ghost]

What do you mean?

[OBattler]

Closing this as it's being tracked in #4044.