kern
annotate src/segm-asm.S @ 7:611b2d66420b
segment descriptors
| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Wed, 16 Feb 2011 07:26:03 +0200 |
| parents | |
| children | 78d5c304ddd0 |
| rev | line source |
|---|---|
| nuclear@7 | 1 .data |
| nuclear@7 | 2 off:.long 0 |
| nuclear@7 | 3 seg:.short 0 |
| nuclear@7 | 4 |
| nuclear@7 | 5 .align |
| nuclear@7 | 6 .short 0 |
| nuclear@7 | 7 gdt_lim: |
| nuclear@7 | 8 .short 0 |
| nuclear@7 | 9 gdt_addr: |
| nuclear@7 | 10 .long 0 |
| nuclear@7 | 11 |
| nuclear@7 | 12 .text |
| nuclear@7 | 13 /* setup_selectors(uint16_t code, uint16_t data) |
| nuclear@7 | 14 * loads the requested selectors to all the selector registers */ |
| nuclear@7 | 15 .globl setup_selectors |
| nuclear@7 | 16 setup_selectors: |
| nuclear@7 | 17 /* setup data selectors */ |
| nuclear@7 | 18 movl 8(%esp), %eax |
| nuclear@7 | 19 movw %ax, %ss |
| nuclear@7 | 20 movw %ax, %es |
| nuclear@7 | 21 movw %ax, %ds |
| nuclear@7 | 22 movw %ax, %gs |
| nuclear@7 | 23 movw %ax, %fs |
| nuclear@7 | 24 /* setup code selector */ |
| nuclear@7 | 25 movl 4(%esp), %eax |
| nuclear@7 | 26 movw %ax, (seg) |
| nuclear@7 | 27 movl $ldcs, (off) |
| nuclear@7 | 28 ljmp *off |
| nuclear@7 | 29 ldcs: |
| nuclear@7 | 30 ret |
| nuclear@7 | 31 |
| nuclear@7 | 32 /* set_gdt(uint32_t addr, uint16_t limit) |
| nuclear@7 | 33 * loads the GDTR with the new address and limit for the GDT */ |
| nuclear@7 | 34 .globl set_gdt |
| nuclear@7 | 35 set_gdt: |
| nuclear@7 | 36 movl 4(%esp), %eax |
| nuclear@7 | 37 movl %eax, (gdt_addr) |
| nuclear@7 | 38 movw 8(%esp), %ax |
| nuclear@7 | 39 movw %ax, (gdt_lim) |
| nuclear@7 | 40 lgdt (gdt_lim) |
| nuclear@7 | 41 ret |