Author: wmb Date: 2009-08-28 22:03:29 +0200 (Fri, 28 Aug 2009) New Revision: 1332
Modified: cpu/x86/pc/resetend.fth Log: resetend.fth - fixed GDT copying problem that was breaking the GRUB-loaded variant.
Modified: cpu/x86/pc/resetend.fth =================================================================== --- cpu/x86/pc/resetend.fth 2009-08-27 18:53:11 UTC (rev 1331) +++ cpu/x86/pc/resetend.fth 2009-08-28 20:03:29 UTC (rev 1332) @@ -10,21 +10,26 @@ \ the pointer since 0 is an invalid descriptor number anyway. gdt-pa # ax mov 0 [ax] sgdt \ Read GDT - 2 [ax] si mov \ GDT base + 2 [ax] bx mov \ GDT base 0 [ax] cx mov \ GDT limit ffff # cx and cx inc
+ gdt-size # cx cmp u> if + gdt-size # cx mov + then + + bx si mov \ Source address for copy - old GDT gdt-pa # di mov \ New GDT base - rep movsb \ Copy ROM GDT to RAM + rep movsb \ Copy old GDT to new GDT
\ Move the code and data descriptors to 60,68 gdt-pa h# 60 + # di mov \ Destination - New descriptor 0x60
- cs si mov 2 [ax] si add \ Source - Current code descriptor + cs si mov bx si add \ Source - Current code descriptor movs movs \ 2 longwords (1 descriptor) -> 60
- ds si mov 2 [ax] si add \ Source - Current data descriptor + ds si mov bx si add \ Source - Current data descriptor movs movs \ 2 longwords (1 descriptor) -> 68
op: gdt-size 1- # 0 [ax] mov \ New GDT size