In
last weeks I
checked which monochrome emulators were done for Atari ST computers
during 3 decades. Probably first one was done in 1987 by Mick West.
Later he made updated version, what was not tied so much for specific
TOS version. Myself added to it half screen mode - for getting sharper
pic. , in those years.
Fastest code is most likely in New Core Monoemulator by Shrimp of New Core. And it has blitter version too, for STEs only. It installs to bootsector of floppy, and work with all regular TOS versions. Unfortunately there are some flaws, probably worst is bad work at 60 Hz refresh rate. And it has only 1 mode 640x400 to 640x200, where grey color is used when 2 pixels in adjacent horizontal lines are black and white. That's the usual way, but sometimes converted pic. is not so sharp. What was the reason to add half screen mode, splitted vertically. And I added quart screen mode, to get proper AR, with sharp pic. 640x400 to 320x200 . Mouse cursor pos determines which part of screen is visible.
Mode 1 - 640x400 px Mode 2 - 640x200 px - half org. screen
Mode 3 - 320x200 px - quart of org screen, correct AR Mode 1 with View as text - better readable
Mode 2 with text view And mode 3 with text View
Switching between modes is with pressing Ctrl + left shift at once. That will work until original TOS keyboard reading code is active - an that's case with almost all GEM (AES, menus, windows) SW .
Beside 3 displaying modes there are 3 versions of SW: CPU only - for ST machines, but can use on STE too. Blitter using v. for STs, works on STEs too. And STE version, which using blitter too, and some video features not present in STs. Code is pretty efficient, what means not much slowdown. Of course, slowdown is smallest in mode 3 - where only quart of screen is processed.
Download: MEQ1
All 3 versions, instructions. Programs work with TOS versions 1.00-2.06 . Need to place in AUTO folder of floppy, or C partition of hard disk.
Fastest code is most likely in New Core Monoemulator by Shrimp of New Core. And it has blitter version too, for STEs only. It installs to bootsector of floppy, and work with all regular TOS versions. Unfortunately there are some flaws, probably worst is bad work at 60 Hz refresh rate. And it has only 1 mode 640x400 to 640x200, where grey color is used when 2 pixels in adjacent horizontal lines are black and white. That's the usual way, but sometimes converted pic. is not so sharp. What was the reason to add half screen mode, splitted vertically. And I added quart screen mode, to get proper AR, with sharp pic. 640x400 to 320x200 . Mouse cursor pos determines which part of screen is visible.
Mode 1 - 640x400 px Mode 2 - 640x200 px - half org. screen
Mode 3 - 320x200 px - quart of org screen, correct AR Mode 1 with View as text - better readable
Mode 2 with text view And mode 3 with text View
Switching between modes is with pressing Ctrl + left shift at once. That will work until original TOS keyboard reading code is active - an that's case with almost all GEM (AES, menus, windows) SW .
Beside 3 displaying modes there are 3 versions of SW: CPU only - for ST machines, but can use on STE too. Blitter using v. for STs, works on STEs too. And STE version, which using blitter too, and some video features not present in STs. Code is pretty efficient, what means not much slowdown. Of course, slowdown is smallest in mode 3 - where only quart of screen is processed.
Download: MEQ1
All 3 versions, instructions. Programs work with TOS versions 1.00-2.06 . Need to place in AUTO folder of floppy, or C partition of hard disk.
PP,
March 2021