State of codepage support? (Germanic umlauts)

[bttrx]

This NASM program should print äöüß + CRLF:

	cpu 8086
	org 256
start:
	mov ah, 9
	mov dx, umlauts
	int 21h
	mov ax, 4C00h
	int 21h

umlauts:
	db 84h	; ä/ä
	db 94h	; ö/ö
	db 81h	; ü/ü
	db 0e1h	; ß/ß
	db 13,10,'$'

but my Linux Mint 22 terminal session shows this instead:

����

If I redirect output to a file and use Double Commander's internal viewer, umlauts and ß are shown correctly only, when I select encodings like, e.g., CP437 or CP850, manually. This may be a desirable behavior when redirecting, but not on the screen, I think.

[dmsc]

Hi!

emu2 has two working modes: full terminal emulation and command line emulation.

In command line emulation, no translation is done because it assumes that the output is meant to be redirected and can contain arbitrary binary data.

In terminal emulation, the full DOS character screen is emulated, and visually presented in the terminal as translated codes.

Currently, emu2 always start at command line emulation, and switches to full screen emulation after the application calls any video function, from this moment on all the normal DOS output is redirected to the full screen emulation.

In your example, as you don't call any video function, the emulator assumes binary data and outputs it untouched.

IMHO, this is the correct behavior as you don't know the type of program you are trying to emulate, and the emulator assumes that it can be called from a script or other program that will parse the output.

Try this program to se your expected output:

	cpu 8086
	org 256
start:
	mov ah, 3
	mov bh, 0
	int 10h

	mov ah, 9
	mov dx, umlauts
	int 21h
	mov ax, 4C00h
	int 21h

umlauts:
	db 84h	; ä/ä
	db 94h	; ö/ö
	db 81h	; ü/ü
	db 0e1h	; ß/ß
	db 13,10,'$'

What do you think could be a better way to handle this?

Have Fun!

[bttrx]

This morning I had the same idea, and yes, it works now. :-)

What do you think could be a better way to handle this?

Dunno… Always start in full screen emulation mode, except when redirection is requested?
From what I remember about DOS is, a DOS program can detect, when stdin/stdout/... is redirected and adapt its behavior accordingly.
So, emu2 probably also knows about the state of redirection and can switch between full screen and command line emulation.
And/Or let me as a user overwrite the emulation mode: EMU2_VIDMODE=[fullscreen|cmdline]

[tkchia]

Hello @dmsc,

I think you could use the POSIX isatty (.) function to check if stdout (or stderr?) is referring to a terminal. This is one way.

Thank you!