OSDev.org

Hello every body. I need help. I use Intel(R) Core(TM)2 Duo CPU P8600 @ 2.40GHz with BIOS v2 mother board. When I start PC (Laptop), BIOS is OK, then my personal loaders loads 40 sectors in memory starting at 0x7000 and I switch to protected mode and my personal software starts and runs correctly. There is only 3 GiB of memory installed and when I read ABAR (5) of the PCI SATA device, the answer is 0xFFCFF000. This Base Address is outside of the memory so of cause I can not use this PCI SATA Device. If I switch to long mode and give 1Gib available for the last GiByte (Top) I can write to 0xFFCFF000 +( Reg num) but nothings appends.
Q: Why BIOS provides ABAR5 outside of memory installed on its mother board.

MMIO is not memory. The ABAR contains the physical address of AHCI MMIO.

Thank you Octocontrabass. Yes of course ! I had forgot this I had modify my PML4E to access to that physical address and now all it is OK. Thank's a lot again. Best regards