Differences

This shows you the differences between two versions of the page.

--- wswan:guide:elf_quirks [2024/09/22 10:32] – asie
+++ wswan:guide:elf_quirks [2024/09/22 11:58] (current) – asie
@@ Line 34: / Line 34: @@
 </code>
-To turn this into a physical address in the cartridge ROM's space, you should use the following equation: ''%%((addr & 0xFFFF) | ((addr & 0x7FF00000) >> 16)) & rom_mask%%''.
+To turn this into a physical address in the cartridge ROM's space, you should use the following equation: ''%%((addr & 0xFFFF) | ((addr & 0x7FF00000) >> 4)) & rom_mask%%''.
+The high four bits of the CPU address are ignored for physical ROM address transformations. This is because their purpose is to tell the compiler/linker at what address the CPU accesses the 64KB bank, not where it is physically stored on the cartridge. For example:
+  * The ELF address ''FFFF0000'' means ''ROM bank 7FF, offset 0000, accessed at F0000 by the CPU'',
+  * The ELF address ''FFF30000'' means ''ROM bank 7FF, offset 0000, accessed at 30000 by the CPU''.
 ELF addresses ''0x00000000 - 0x0000FFFF'' correspond to IRAM addresses.