How are 1 byte ASCII characters programmed to SJIS text based games that don't support it?

[YetAnother]

I saw the Segagaga translation group did it, but I haven't found any detailed information about it.
Single byte roman letters don't seem to work 61=a, but the two byte style does work 8281=a; it was explained that characters were taken from the BIOS.
Thanks in advance.

 

[Knight0fDragon]

I do not understand the question? Based on my assumption, you just have a translation function. If first byte < 0x80, then it is not Shift JIS. Take that byte, and add 0x8220 to it (or other offsets to convert ascii to shift jis)

 

[YetAnother]

I want to know this process:
"The biggest hurdle facing any translation patching attempt is actually the way the game was originally programmed to draw text from the Dreamcast's BIOS, as opposed to using a font sheet, like many Dreamcast games do. While the core of this issue has been solved by some exceptionally talented hackers in the Dreamcast fan community, there is still much to be worked on."

An Interview with Tetsu "Tez" Okano - the Mastermind behind Cult Dreamcast RPG Segagaga

www.thedreamcastjunkyard.co.uk

 

[Mr Conan]

The hurdle is: learn assembly, learn how to use ghidra, decide whether you do what kod mentioned above or inject your own font sheet.

 

[Knight0fDragon]

I want to know this process:
"The biggest hurdle facing any translation patching attempt is actually the way the game was originally programmed to draw text from the Dreamcast's BIOS, as opposed to using a font sheet, like many Dreamcast games do. While the core of this issue has been solved by some exceptionally talented hackers in the Dreamcast fan community, there is still much to be worked on."

An Interview with Tetsu "Tez" Okano - the Mastermind behind Cult Dreamcast RPG Segagaga

www.thedreamcastjunkyard.co.uk

I do not know their particular process, but they found the function that uses the DC BIOS font and figured out a way to use it to their advantage. The parts that need to be worked on are probably characters not available in the BIOS font set.