How BASIC Compresses Error Messages

[Bread80]

Amstrad CPC BASIC uses a unique compression method to save a few bytes in the way it stores error messages.

In my blog post I explore how it works, how many bytes it saves, how many extra bytes of code it adds, and why it's not used for other system messages.

http://bread80.com/2022/09/21/how-amstrad-cpc-basic-compresses-error-messages/

[Urusergi]

Very interesting, I really like your articles, are a luxury 

Do you plan to do something with all the information? new roms? basic 1.2? 
People say I'm good at optimizing , but it seems a project too big for me. 

cheers.

[zhulien]

Really crazy what they did to save bytes.  Not as radical as the error message partials is the crazy keyword savings, but i think I mentioned the method they did for this balances the time to look up for keywords somewhat instead of sequentially or perhaps binary searching for the keyword.  The error handling however is still a puzzle in some areas, like... where does basic actually flag or store that an error occurred for later reporting of the error?

[d_kef]

The same compression method was used in CP/M for displaying all system messages.

d_kef