Daewoo CPC-400S hanja display bug.

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By masquane

Supporter (6)

Аватар пользователя masquane

29-05-2019, 14:46

On Daewoo CPC-400S, later DC95 hanja (kanji) fonts does not display correctly.

10 SCREEN 9:WIDTH 64
20 FOR I=0 TO 14
30 PRINT CHR$(&HDC);CHR$(&H90+I);
40 NEXT I

The correct is

讃賛察札参倉創唱彰昌暢窓蒼債彩

There are no fonts later DC95 in cpc-400s_hangulfont.rom
Maybe the file size is not enough.

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By Manuel

Ascended (15686)

Аватар пользователя Manuel

29-05-2019, 22:26

You mean the ROM dump is probably incomplete?

By RetroTechie

Paragon (1563)

Аватар пользователя RetroTechie

30-05-2019, 03:32

Should be easy to check. The font ROM in CPC-400S is a Nec 23C2000 or equivalent. That is: a 2 Mbit (256 KB) type. The other 2 ROMs (marked U38 and U44) are 64 KB each.

So a) file size of ROMs that OpenMSX uses for this machine should total 256+64+64 KB.
And b) when that 256 KB ROM is put into a hex viewer, there should be no large 'empty' areas in it. It's a mass-produced mask ROM, with 2 Mbit size no way there'd be (for example) 1 1/4 Mbit worth of data in there.

By rderooy

Hero (578)

Аватар пользователя rderooy

30-05-2019, 10:18

The font rom file is 128kB, not 256.

32K cpc-400s_basic-bios2.rom
16K cpc-400s_disk.rom
128K cpc-400s_hangulfont.rom
32K cpc-400s_hangul.rom
32K cpc-400s_msx2sub.rom

By Manuel

Ascended (15686)

Аватар пользователя Manuel

30-05-2019, 11:15

So, incomplete then, right?

By mars2000you

Enlighted (5495)

Аватар пользователя mars2000you

30-05-2019, 12:57

The blueMSX machine has the 256kB rom.

By Manuel

Ascended (15686)

Аватар пользователя Manuel

30-05-2019, 13:06

The font ROM is mechanism is the same as a Kanji font ROM. If the font ROM is 256kB, the software will access also I/O ports 0xDA and 0xDB. But when I try this in openMSX, the ROM is only accessing 0xD8 and 0xD9 ports, which fits with a 128kB font ROM (JIS1 in Japanese machines).

By Manuel

Ascended (15686)

Аватар пользователя Manuel

30-05-2019, 13:43

Perhaps it would be good if an owner of the machine would dump the ROMs again.
The ROMs in openMSX do not match those of blueMSX (specifically: the hangul driver). I added the CPC-400S in 2003 and I can't find back the source of the information. For the origin of the blueMSX ROMs, perhaps mars2000you can elaborate on that.

To be sure of everything: if you own this device, please speak up so we can redump the ROMs, to be absolutely sure.

EDIT: even with the blueMSX Hangul Driver and font ROM, I get the same output. The software is only accessing I/O port 0xD9.

By gdx

Prophet (2977)

Аватар пользователя gdx

30-05-2019, 16:02

Indeed, I tryed the program on CocoaMSX (256kB Rom) and OpenMSX (128kB Rom) and I get something like below on both:

讃賛察札参 、。・‥…¨”–—

By RetroTechie

Paragon (1563)

Аватар пользователя RetroTechie

30-05-2019, 20:17

I have contents of both 64 KB ROMs on file. Dumped personally using an EPROM programmer back in the day (file dates suggest in '94, sounds about right). There's an empty block of 16 KB in one of the ROMs. That explains why the smaller ROMs add up to 112 rather than 128 KB. Did some modifications to one of the ROMs then, among other things greatly speeding up the floppy drive (which is rather slow on the CPC-400S).

Don't have the font ROM though. Seemed too much work @ the time since the chip wasn't in a socket (and 40 pins rather than 28 or 32 pins), and I didn't know how it was addressed software-wise.

Chances are good this is some kind of industry standard ROM though (like Japanese JIS1&2). So rip that ROM from some other Korean machine that has such a font ROM, and I bet they'll be the same.

By Manuel

Ascended (15686)

Аватар пользователя Manuel

30-05-2019, 21:07

RetroTechie: if you have them unmodified, I'm interested to study them.

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