diff options
Diffstat (limited to 'arch/i386/boot')
| -rw-r--r-- | arch/i386/boot/setup.S | 68 |
1 files changed, 29 insertions, 39 deletions
diff --git a/arch/i386/boot/setup.S b/arch/i386/boot/setup.S index 32d852efc..7553ce943 100644 --- a/arch/i386/boot/setup.S +++ b/arch/i386/boot/setup.S @@ -26,6 +26,10 @@ ! ! Video handling moved to video.S by Martin Mares, March 1996 ! <mj@k332.feld.cvut.cz> +! +! Extended memory detection scheme retwiddled by orc@pell.chi.il.us (david +! parsons) to avoid loadlin confusion, July 1997 +! #define __ASSEMBLY__ #include <linux/config.h> @@ -241,53 +245,39 @@ loader_panic_mess: loader_ok: ! Get memory size (extended mem, kB) -#ifdef STANDARD_MEMORY_BIOS_CALL - mov ah,#0x88 - int 0x15 - mov [2],ax -#else - push ax - push cx - push dx - ! which bootloader ? - seg cs - mov al,byte ptr type_of_loader - and al,#0xf0 - cmp al,#0x10 - jne try_xe801 ! not Loadlin - seg cs - cmp byte ptr type_of_loader,#0x16 - jbe oldstylemem ! Loadlin <= 1.6 don't like that -try_xe801: - mov ax,#0xe801 - int 0x15 - jc oldstylemem +#ifndef STANDARD_MEMORY_BIOS_CALL + push ebx + + xor ebx,ebx ! preload new memory slot with 0k + mov [0x1e0], ebx + + mov ax,#0xe801 + int 0x15 + jc oldstylemem -! memory size is (ax+(64*bx)) * 1024; we store bx+(ax/64) +! memory size is in 1k chunksizes, to avoid confusing loadlin. +! we store the 0xe801 memory size in a completely different place, +! because it will most likely be longer than 16 bits. +! (use 1e0 because that's what Larry Augustine uses in his +! alternative new memory detection scheme, and it's sensible +! to write everything into the same place.) - mov [2],bx ! store extended memory size - xor dx,dx - mov cx,#64 ! convert lower memory size from K into - div cx ! 64k chunks. + and ebx, #0xffff ! clear sign extend + shl ebx, 6 ! and go from 64k to 1k chunks + mov [0x1e0],ebx ! store extended memory size - add [2],ax ! add lower memory into total size. - jmp gotmem + and eax, #0xffff ! clear sign extend + add [0x1e0],eax ! and add lower memory into total size. + + ! and fall into the old memory detection code to populate the + ! compatability slot. + pop ebx oldstylemem: +#endif mov ah,#0x88 int 0x15 - or ax,ax ! some BIOSes report ZERO for 64meg - mov word ptr [2],#0x400 - jz gotmem - mov cx,#64 ! got memory size in kbytes, so we need to - xor dx,dx ! adjust to 64k chunks for the system. - div cx mov [2],ax -gotmem: - pop dx - pop cx - pop ax -#endif ! Set the keyboard repeat rate to the max |