09-17-2012, 04:17 PM
I were starting to create files with random or hex-edited content similar to pacman.zip (mame), and also using the information from - <!-- m --><a class="postlink" href="http://www.ascotti.org/programming/pie/hardware.htm">http://www.ascotti.org/programming/pie/hardware.htm</a><!-- m --> - and i'm starting to know how this machine works (but i didn't start to code anything yet on zxbasic-compiler for that)
(overally, pacman.6e , *.6f, *.6h and *.6j are 4 4kb files for the program (a 16kb limit splitted into 4), pacman.5e is the character set (4kb), pacman.5f is the sprite set (4kb), 82s123.7f the palette (32 bytes - it's from a colourspace similar used on msx2-screen8 or UzeBox ), and 82s126.4a the clut (how the palette is arranged in groups of 4 colours - 256 bytes) - and i think 82s126.1m and *.3m are related to sound (256 bytes each) )
This machine seems to be not that plenty of ram memory (it's an arcade machine from 1980), around 4kb at most, which 2k is for displaying patterns (and the bitmaps (background patterns (8x8 characters), sprites (16x16) ) are stored in 8kb of rom somewhere else)
So, it seems that almost 2k of free ram makes it difficult to deal with the stack point, isn't it? and anyway, must we set that into a specific area, like 0x07EF, before the code starts? how much ram much we count with like on a regular use of functions and routines, and which care must we have?
(overally, pacman.6e , *.6f, *.6h and *.6j are 4 4kb files for the program (a 16kb limit splitted into 4), pacman.5e is the character set (4kb), pacman.5f is the sprite set (4kb), 82s123.7f the palette (32 bytes - it's from a colourspace similar used on msx2-screen8 or UzeBox ), and 82s126.4a the clut (how the palette is arranged in groups of 4 colours - 256 bytes) - and i think 82s126.1m and *.3m are related to sound (256 bytes each) )
This machine seems to be not that plenty of ram memory (it's an arcade machine from 1980), around 4kb at most, which 2k is for displaying patterns (and the bitmaps (background patterns (8x8 characters), sprites (16x16) ) are stored in 8kb of rom somewhere else)
So, it seems that almost 2k of free ram makes it difficult to deal with the stack point, isn't it? and anyway, must we set that into a specific area, like 0x07EF, before the code starts? how much ram much we count with like on a regular use of functions and routines, and which care must we have?