Re: DOS2 & 4MB (and a little GEM news)
On Wed, 23 May 2001, Patriek Lesparre wrote: >According to my tests with a 4MB mapper, DOS2 indeed lists it as 255 >segments (4080kB) and trying to allocate all segments does result in >segment 256 being ignored! > >Questions: The question is: do you really care for what happens to those 16Kb when you have 4096Kb installed? ;) Regards, -- [EMAIL PROTECTED] - http://www.aamsx.org -- For info, see http://www.stack.nl/~wynke/MSX/listinfo.html
Re: DOS2 & 4MB (and a little GEM news)
> According to my tests with a 4MB mapper, DOS2 indeed lists it as 255 > segments (4080kB) and trying to allocate all segments does result in > segment 256 being ignored! Yes, that's because it is impossible to say "256" with just one byte. A solution would be to use this byte as "number of segments minus one" counter, but since value 0 is used as the end of segments table mark, a theorical 1-segment mapper could not be correclty used then. > 3. Do the 2 DOS2 system segments reside in segment 254 and 255? Good question. I have a 4Mb mapper, but since Turbo-R uses always internal mapper as primary one, I can't check this out. But if DOS 2 is consistent, segment 255 should be always ignored, even for using system segments. > I think it would've been better if DOS2 counted from 0, not from 1 :( Oh, come on! Really you miss these 16K when having 4080K available?? 8-) *** XX MSX USERS MEETING IN BARCELONA: DECEMBER 8th 2001 *** -- Konami Man - AKA Nestor Soriano (^^)v http://www.konamiman.com- [EMAIL PROTECTED] ICQ#: 18281450 "Celebrating the imprudences must be unfailingly consequent with it said, not for the fact in itself, but for some that another onomatopoeia to the use" -- -- For info, see http://www.stack.nl/~wynke/MSX/listinfo.html
DOS2 & 4MB (and a little GEM news)
Hi all! I'm using the MSX-DOS2 mapper support routines and found something strange. According to the docs the total nr of segments listed in the Mapper Variable Table can contain 1-255. But a 4MB mapper has 256 segments! According to my tests with a 4MB mapper, DOS2 indeed lists it as 255 segments (4080kB) and trying to allocate all segments does result in segment 256 being ignored! Questions: 1. Is there a way around this? 2. It seems segment 256 is always free, is that a safe assumption? 3. Do the 2 DOS2 system segments reside in segment 254 and 255? I think it would've been better if DOS2 counted from 0, not from 1 :( Greetz, Patriek PS: Oh, I promised some GEM news :) On Tilburg 2001 I announced (ahum, stuck a paper on the TNI booth ^^;) a version of GEM using Dynamic Recompilation. At the time there was still a bug in it, but not anymore. My current development version is running around 25% faster on a normal MSX2. You need quite a bit of memory though (2x ROM-size + whatever else available). I don't know when a release will take place, but I'm working on it! ^_^ -- For info, see http://www.stack.nl/~wynke/MSX/listinfo.html
