'What' used spare memory on the TMS9918 Video Display Controller?
By 'what', was it
- Something pre-installed on the computer like Bios or Basic or something, I assume the main cpu s themselves were not advanced enough to decide when and how to use that spare memory themselves.
- Or, was it done by software loaded onto the machine from external memory like disk or cassette .
Quote from the Wikipedia page -
Depending on the screen mode being used, not all of the video memory may be needed to generate the display. In these cases, the CPU may use the extra video memory for other purposes. For example, one use is as a scratch-pad for uncompressing graphics or sound data stored in cartridge ROM into. Another popular use is to create a second copy of some or all of the display data to eliminate flickering and tearing, a technique known as double buffering.