On Tue, Nov 24, 2009 at 07:53:33PM +0900, Philip Lord wrote: > Just a quick follow up, and a question for the list: > The original character ROM contains two sets of capital letters, and on > set of lower case. Does anyone know why there are two sets of cap > letters? There actually are two 128-char character sets in Commodore 8-bit computers: uppercase/graphics and lowercase/uppercase. On models where reverse characters are not implemented in hardware, the character sets are 256-char, but the upper half is the same as the lower half, but inverted. In the home computers (VIC-20 and later), you can switch between these two character sets by pressing SHIFT and the C= key. If I remember correctly, that does not work in the PET. But these control codes should work: print chr$(14); rem ctrl-n selects lower/upper-case print chr$(142); rem shift-ctrl-n selects uppercase/graphics print chr$(8); rem ctrl-h disables SHIFT+C= print chr$(9); rem ctrl-i enables SHIFT+C= Some graphic characters exist (and are identical) in both sets. These graphics are what you obtain on the VIC-20 and later when pressing the C= key together with a letter key. > Presently I have replaced the lowercase letter set with the new Japanese > fonts. Hopefully this was the correct thing to do. A poke 59468,14 should > activate them. However you do lose the lowercase characters of course. If > you believe I have made a mistake, please let me know. I am just guessing, but I would expect that the original font preserved positions 1 to 26 (a to z) intact. Those would correspond to the lower case letters in the lower/uppercase character set. If the Japanese glyphs are put where the uppercase letters used to be (65 to 138), then it would make sense to replace the lowercase glyphs with uppercase ones at 1 to 26. For what it is worth, I found a homebrew EPROM in a VIC-20 that had replaced some of the C= graphics characters with accented letters. The official Swedish/Finnish modification had the chars at [\]. Marko Message was sent through the cbm-hackers mailing listReceived on 2009-11-25 08:30:20
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