Anyone able to patch COMMAND.COM for me?

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By wimpie3

Champion (264)

Аватар пользователя wimpie3

26-04-2019, 10:48

Is anyone here able to create a patched COMMAND.COM for me? I want to completely hide the DOS boot process and start a COM file without the user noticing.

Hiding the MSX DOS version is easy (just replace the texts with 00's in MSXDOS.SYS). However, COMMAND.COM always shows "A>NAME.COM" if you launch a program using autoexec.bat. Also, on a MSX1 you get a date prompt (that needs to be skipped as well).

Для того, чтобы оставить комментарий, необходимо регистрация или !login

By mtn

Master (248)

Аватар пользователя mtn

26-04-2019, 11:00

Is this for some MSX barcade or something?

By wimpie3

Champion (264)

Аватар пользователя wimpie3

26-04-2019, 11:07

No, for my next MSXdev game.

By Pencioner

Paladin (982)

Аватар пользователя Pencioner

26-04-2019, 11:21

i think the easiest way is to just find the bytes of string "COMMAND COM" in the MSXDOS.SYS file and replace with "MYGAME COM" Cool

actually, there's a code which runs the COMMAND.COM and the name is hardcoded, so whenever you replace name - it should run your file instead. name is iirc already in FCB data format, so it is 11 bytes (8 for name padded with spaces at the end if shorter and 3 for extension). i remember i did something like that back in 1995 and it worked Wink

By wimpie3

Champion (264)

Аватар пользователя wimpie3

26-04-2019, 11:58

@pencioner Yeah, I tried that too, unfortunately it seems COMMAND.COM loads up a few things in memory and cannot be left out. COMMAND.COM has to be launched first, BEFORE I can launch my COM game.

By larsthe18th

Master (159)

Аватар пользователя larsthe18th

26-04-2019, 12:38

You can disable the screen in the bootsector of the disk, and put it back in when your game starts.
I used this trick in one of my projects

By wimpie3

Champion (264)

Аватар пользователя wimpie3

26-04-2019, 12:44

I've heard about this technique before. Would you be able to create me a MSX-DOS1 bootable DSK file with the screen disabled?

By larsthe18th

Master (159)

Аватар пользователя larsthe18th

26-04-2019, 13:12

Sure, have uploaded a DSK image with the Disable screen in the bootsector,it boots to DOS.
Just boot up the DSK and type mode 80 to enable the screen.

By wimpie3

Champion (264)

Аватар пользователя wimpie3

26-04-2019, 13:49

Works perfect! Thanks a million!

By ericb59

Paladin (875)

Аватар пользователя ericb59

26-04-2019, 21:35

hello Larsthe18th,

How do you write your binary to the boot sector of a disk image ?

By NYYRIKKI

Enlighted (5396)

Аватар пользователя NYYRIKKI

26-04-2019, 22:18

ericb59 wrote:

How do you write your binary to the boot sector of a disk image ?

Bootsector will be loaded to #C000 ... Entrypoint is #C01E IIRC... It is called two times. Once before RAM init and once after it. C-flag tells which call is in question.

... if you meant physically, please see BASIC DSKI$-function and DSKO$-instruction. (Sorry I can't link to DSKI$(), but there is link on DSKO$ page)

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