+Gemintronic Posted July 16, 2018 Share Posted July 16, 2018 After not having success with the search function I thought to ask: Is there a list of confirmed safe variables freed when using certain kernel options? For instance: when using set kernel_options player1colors no_blank_lines Does that mean it frees up missile0x, missile0y, missile1x, missile1y, missile0height, missile1height Quote Link to comment Share on other sites More sharing options...
RevEng Posted July 16, 2018 Share Posted July 16, 2018 For instance: when using set kernel_options player1colors no_blank_lines Does that mean it frees up missile0x, missile0y, missile1x, missile1y, missile0height, missile1height No. One rule of thumb you can keep in mind is that usually the X variables stick around. Otherwise the trick of turning on ENAM0 and positioning the missile wouldn't work. The other variables are (almost?) always consumed. If I open up 2600basic.h, I can see that "player1color = $87", and "missile1height = $87". That means when player1color is being used, it consumes that missile1height memory location. I know from experience that player1color is actually 2 bytes, so it also consumes "$88". 2600basic.h says "missile1y = $88", so that variable is gone too. Similar comparisons can be made to show player0color eats up missile0y and missile0height. I leave those as an exercise to the reader. 1 Quote Link to comment Share on other sites More sharing options...
+Gemintronic Posted July 16, 2018 Author Share Posted July 16, 2018 Thank you for the info RevEng. Back to reducing playfield rows and re-writing code to use boolean flags instead of whole vars. Quote Link to comment Share on other sites More sharing options...
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