English Amiga Board - View Single Post - Hardcode bitplane pointers in copperlist?

a/b · 19 April 2024, 18:10

If your bitmap is in a relocatable section (e.g. SECTION xyz,DATA_C) you cannot take a shortcut. You have to set the bitmap pointers in copperlist manually with CPU because you don't know at what address will bitmap be when your program is executed, and you are trying to split that address in two halves (not supported).
You can do that only when the bitmap address is known at compile/assemble time (and that requires absolute address).
There is a similar thread (different problem, but the same reason why not) which should explain the program loader's limitations in regard to address manupulation in more detail: https://eab.abime.net/showthread.php?t=117217

19 April 2024, 18:10	#11
a/b Registered User Join Date: Jun 2016 Location: europe Posts: 1,044	If your bitmap is in a relocatable section (e.g. SECTION xyz,DATA_C) you cannot take a shortcut. You have to set the bitmap pointers in copperlist manually with CPU because you don't know at what address will bitmap be when your program is executed, and you are trying to split that address in two halves (not supported). You can do that only when the bitmap address is known at compile/assemble time (and that requires absolute address). There is a similar thread (different problem, but the same reason why not) which should explain the program loader's limitations in regard to address manupulation in more detail: https://eab.abime.net/showthread.php?t=117217