Sound works in the first mission when you configure a joystick in DOSBox, but it's not entirely effective because sound is still missing on the title and prologue screens. Sound works completely, regardless of gameport detection, when booting real DOS. The game uses hard-coded memory addresses that belong to DOS and relies on pre-existing memory values; which is weird and/or messy programming.

Although DOSBox allocates the memory region for its emulated DOS structures, it is not actually using the specific addresses, so a workaround is possible. The attached program sets memory values that should enable all sound in the game without having to boot DOS and without having to configure a joystick.

Thank you!

with which table would this correspond ?

ripsaw8080 wrote:

The game uses hard-coded memory addresses that belong to DOS and relies on pre-existing memory values; which is weird and/or messy programming.

The bit about messy programming I can believe. I remember when the game was released in 1995, it ran way too fast even on 486/66 computers, you had to use the "Turbo" button to make it playable.

Later I learned the game had a complicated production. It was supposed to appear as early as 1991-92 for Amiga and Atari ST. They probably cut corners to convert it to PC.

It uses segment 0x40 addresses 0x4F0 thru 0x4FF and 0x9EA (I think 0x9EA was not intended, should have been 0x4F0+0xA like the rest of the code, not 0x4F0+0x4FA)

In DOS 5/6 the addresses are not part of a table, they are actually DOS code. The game swaps between several executables, and maybe the developer was being lazy by storing global vars in a mostly-dormant area of DOS. In DOS 3.3 the addresses are part of a device table, but with the game being from 1995, earlier versions of DOS were probably not seeing much use by then.