Great Hierophant wrote:

However, I must report two don'display properly with the cga machine setting. These two are Icon and The Seven Spirits of Ra.(...) In the CGA mode, Icon will not show a correct graphics display and Seven Spirits will not even start.

I checked with the original icondemo (attached here), and it indeed doesn't work correctly. The Seven Spirits of Ra not starting may be due to a different problem, however, as the program cannot know whether DOSbox correctly implements the CGA-emulation or not (especially since all CGA registers are write-only).

JAL

I remember one of them doing something very nasty with rewriting some bios table and then setting the videomode which isn't exactly supported 😀

Harekiet wrote:

I remember one of them doing something very nasty with rewriting some bios table and then setting the videomode which isn't exactly supported 😀

They set the characterheight, and disable the blinking bit, that's about it, afaik. There's very little trickery possible with CGA, due to it limited number of registers. There's only one BIOS-table used for CGA, which stores the current value of the CGA registers (since the actual registers are write-only). A call to the BIOS to set the videomode would overwrite these. Besides, why wouldn't this be "exactly supported"? I presume the CGA emulation of DOSbox is aimed at 100% CGA hardware compatibility? (Okay, safe maybe some screenadjustment CRT-regs, which can be ignored most of the time.) It's a bug Harekiet, go fix it you lazy ... 😀

B.t.w., did anyone check Round42 or Bricks? They use the same trick.

Update: I checked Round42, it works as supposed.

JAL

While I'm on the subject of text bugs, I might mention two other games that suffer from them. Microsoft Adventure, released with the IBM PC Model 5150 back in 1981 uses the 40-column text mode. With all DosBox graphics options, the first three text columns are blacked out, making it difficult to read the remaining text. Also, in King's Quest booters for the IBM PC and Tandy 1000, the inventory screen will be totally black unless the VGA graphics mode is selected. It does work in King's Quest II and The Black Cauldron booters using CGA and Tandy modes.