I did some experimenting with MSVC 5.1, and it's weird. I get the same strings in the exe as carmen.exe has, but the code itself looks completely different.

either I set up my compiler wrong, or this game is full of assembly even for very simple functions

I don't know exactly what this function does (I know it sets some flags based on something in the graphics context) but I DO know one important thing about it:

they included it in the final binary FOUR TIMES.

byte-identical.

this is a compiler & linker from 1988, it doesn't understand how to merge identical copies of functions apparently

I found another function which has 4 copies.

I'm starting to suspect this program originally had 4 C source files and the linker wasn't optimizing this

wait I bet it's drivers!
like, one version of this function is called by VGA_DrawFuncUnknown and nothing else.
Another one? CGA/Hercules.
the third? EGA
The last? Tandy.

They compiled the 4 video drivers separately, and then linked them into the EXE, with no deduplication across compile units

yeah. Found another: VGAMalloc is the same as CGAMalloc (and Hercules doesn't have it's own HerculesMalloc, because it's in the same code unit as CGA: So it just uses CGAMalloc)
Tandy has TandyMalloc.

But not EGAMalloc. That one is completely different.

the DrawLine API is weird.
To draw the horizontal underline for the hotkeys in the menu, it calls DrawLine(0, -width).

It's DrawLine(int y, int x), and yeah you pass negative numbers

it's also off by one.
because 0,0 is silly, you're always drawing at least one pixel. So DrawLine(0, -5) draws a six pixel wide horizontal line to the left

PUSH BX
PUSH ES
PUSH SI
CALL StartPlayingSound
POP BX
POP ES
POP SI

since when has the x86 stack been FIFO instead of LIFO?

the internal audio API used by this game is interesting.
LoadAndPlaySoundChunk is called with a chunk name from digisnd.dat, but you can also pass -1 or 0. I'm not sure what -1 does yet (maybe silence a currently playing sound?) but 0 means "wait until the sound finishes"

I'm not really sure why it works that way, especially because calling LoadAndPlaySoundChunk(0) is equivalent to calling WaitUntilSoundFinishes().

So why not just do that instead?

uh oh. the computer noise is triggered with:
LoadAndPlaySoundChunk(217)

but I look in the DIGISND.DAT file and it has chunks 200-216.

So either my DAT file parsing is wrong or it's loading sounds from elsewhere, somehow? because the sound DOES play, so it's not just an error

I thought it might just be playing from MIDISND.DAT instead (since the computer noise is very beepy, maybe it's just a synth sound?) but MIDISND.DAT starts at chunk id 218 and goes up.

WHERE IS 217?

huh. weird. when you try to backspace too far in the name entry screen, it goes "duh-nuh" at you, but that isn't connected to a LoadAndPlaySoundChunk call.

So it's using a different function for this ONE NOISE?

maybe it's hardcoded to pc speaker and I can't tell the difference between soundblaster and pc speaker because they're both coming out of the same laptop

YEP. muted my soundblaster (MIXER SB 0:0) and it's still duh-nuhing at me.

why would you do this to me, brøderbund?

ah-ha! I found 217.

DIGISND.DAT has PCM sound effects for 200-216.
But there's also chunks in CARMEN.DAT for 200-229.

I didn't think the ones in CARMEN.DAT were sound files because they're so small... but they're just the right size to be PC speaker sound effects!

the way the game works is that it loads CARMEN.DAT always, then if you have a sound card it supports, it loads DIGISND.DAT which replaces chunks 200-216 in memory with the DIGISND.DAT ones, which are PCM. But if you don't have a sound card, it still has the CARMEN.DAT ones loaded, and they're all pc speaker sound effects.

they hardcoded two sound effects into the EXE and the rest are loaded from the DAT files.

eww. Someone hacked something in at the last moment!

yeah lets just return 17 bits from this function WHY NOT there are no rules