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sorgelig / ZX_Spectrum-128K_MIST

ZX Spectrum 128K for MIST Board
GNU General Public License v2.0
31 stars 18 forks source link

upd765 optimization + Pentagon1024 #17

Closed gyurco closed 6 years ago

gyurco commented 6 years ago

Hi!

There were some patches in my tree, so I decided to create this PR. I think you can use them for MiSTer, too, if you want.

sorgelig commented 6 years ago

Thanks for patches! I've used Pentagon 512K because it's highest memory size backward compatible with Pentagon 128K paging model. Ok. Let's switch to Pentagon 1024K.

gyurco commented 6 years ago

Thanks for merging! I've just found this Robocop 1024k remix, and wanted to make it work. I never used anything Pentagon 512k specific, hope the patch won't break anything.

gyurco commented 6 years ago

Well, I'm almost sure that 48k mode will not disable paging now, because now bit2 in #effd should be set to 1 first. So for a real 48k mode: OUT 61431,4 OUT 32765,48

gyurco commented 6 years ago

Yepp, confirmed with JetPac/keyboard mode, 48k mode doesn't disable paging. Maybe the ROM was modified in the real Pentagon 1024 to do the extra OUT.

sorgelig commented 6 years ago

Pentagon 1024 had its own ROM as far as i remember. Since we have a separate Pentagon 128K, it's OK.