Mclaneinc Posted November 12, 2020 Share Posted November 12, 2020 I'm getting 37902 but its supposed to be a 64K machine...SysCheck says its fine and I'm sure it is but, is BASIC blanking it out? Sorry...Having a senior moment (again) Quote Link to comment Share on other sites More sharing options...
Goochman Posted November 12, 2020 Share Posted November 12, 2020 Thats the correct amount - you need to bankswitch in 16k blocks to utilize all 64k. Quote Link to comment Share on other sites More sharing options...
Mclaneinc Posted November 12, 2020 Author Share Posted November 12, 2020 Thank you, was confused by the numbers.. Much appreciated Paul... Quote Link to comment Share on other sites More sharing options...
Mclaneinc Posted November 12, 2020 Author Share Posted November 12, 2020 Mods can delete this thread if they want... Quote Link to comment Share on other sites More sharing options...
zzip Posted November 12, 2020 Share Posted November 12, 2020 6502 can only see 64K at one time, if you have more than that, banks have to be switched in and out. the OS Rom is 16K and blocks access to the top 16K Ram unless bank switching is used The Basic ROM is 8K and blocks 8K RAM (this can be bank-switched as well) That means 40K RAM left, minus a few K for housekeeping stuff. 3 Quote Link to comment Share on other sites More sharing options...
Tickled_Pink Posted November 12, 2020 Share Posted November 12, 2020 46 minutes ago, Goochman said: Thats the correct amount - you need to bankswitch in 16k blocks to utilize all 64k. No. It's BASIC and the OS taking it up. The 6502 can directly access all 64K. Bank switching only comes into play once you have more than 64K in a machine, such as on the 130XE. 1 Quote Link to comment Share on other sites More sharing options...
Mclaneinc Posted November 12, 2020 Author Share Posted November 12, 2020 (edited) I really should know all this stuff re the machines, I used to keep up on it but I just lapsed and now its just all fragmented in my head.. Thanks all... Edited November 12, 2020 by Mclaneinc Quote Link to comment Share on other sites More sharing options...
zzip Posted November 12, 2020 Share Posted November 12, 2020 Just now, Tickled_Pink said: No. It's BASIC and the OS taking it up. The 6502 can directly access all 64K. Bank switching only comes into play once you have more than 64K in a machine, such as on the 130XE. It is possible to temporarily switch off BASIC and the OS area to gain access to that extra 24K RAM. You do have to be very careful how you do it so you don't lock up the system. It would require ML routines from a BASIC program. Quote Link to comment Share on other sites More sharing options...
SoundGammon Posted November 12, 2020 Share Posted November 12, 2020 Try using Turbo Basic, it sits under the ram of the OS and gives you more free memory! 1 Quote Link to comment Share on other sites More sharing options...
ivop Posted November 12, 2020 Share Posted November 12, 2020 2 hours ago, zzip said: It is possible to temporarily switch off BASIC and the OS area to gain access to that extra 24K RAM. You do have to be very careful how you do it so you don't lock up the system. It would require ML routines from a BASIC program. 22kB. The hardware register region cannot be switched to RAM 1 Quote Link to comment Share on other sites More sharing options...
xxl Posted November 12, 2020 Share Posted November 12, 2020 1 hour ago, ivop said: 22kB. The hardware register region cannot be switched to RAM with MapRAM modification can. RAM under hardware registers is mapped to $5000 area similar to Self-Test Quote Link to comment Share on other sites More sharing options...
+CharlieChaplin Posted November 12, 2020 Share Posted November 12, 2020 36 minutes ago, xxl said: with MapRAM modification can. RAM under hardware registers is mapped to $5000 area similar to Self-Test But then it is no longer an original Atari. ;-) 2 Quote Link to comment Share on other sites More sharing options...
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