Problems encountered during simple task switching in linux0.11

The problem encountered during simple task switching in linux0.11-general Linux technology-Linux technology and application information. The following is a detailed description.

CODE :! Boot. s ! ! It then loads the system at 0x10000, using BIOS interrupts. Thereafter ! It disables all interrupts, changes to protected mode, and callthe BOOTSEG = 0x07c0 SYSSEG = 0x1000! System loaded at 0x10000 (65536 ). SYSLEN = 17! Sectors occupied. Entry start Start: Jmpigo, # BOOTSEG Go: movax, cs Movds, ax Movss, ax Movsp, #0x400! Arbitrary value> & gt; 512 ! OK, we 've written the message, now Load_system: Movdx, #0x0000 Movcx, #0x0002 Movax, # SYSSEG Moves, ax Xorbx, bx Movax, #0x200 + SYSLEN Int 0x13 Jncok_load Die: jmpdie ! Now we want to move to protected mode... OK _load: Cli! No interrupts allowed! Movax, # SYSSEG Movds, ax Xorax, ax Moves, ax Movcx, #0x2000 Subsi, si Subdi, di Rep Movw Movax, # BOOTSEG Movds, ax Required tidt_48! Load idt with 0, 0 Lgdtgdt_48! Load gdt with whatever appropriate ! Absolute address 0x00000, in 32-bit protected mode. Movax, #0x0001! Protected mode (PE) bit Lmswax! This is it! Jmpi0, 8! Jmp offset 0 of segment 8 (cs) Gdt:. word0, 0, 0! Dummy . Word0x07FF! 8 Mb-limit = 2047 (2048*4096 = 8 Mb) . Word0x0000! Base address = 0x00000 . Word0x9A00! Code read/exec . Word0x00C0! Granularity = 4096,386 . Word0x07FF! 8 Mb-limit = 2047 (2048*4096 = 8 Mb) . Word0x0000! Base address = 0x00000 . Word0x9200! Data read/write . Word0x00C0! Granularity = 4096,386 Idt_48:. word0! Idt limit = 0 . Word0, 0! Idt base = 0L Gdt_48:. word0x7ff! Gdt limit = 2048,256 GDT entries . Word0x7c00 + gdt, 0! Gdt base = 07xxx . Org 510 . Word 0xAA55