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| author | Michal Idziorek <m.i@gmx.at> | 2015-05-14 10:44:00 +0200 |
|---|---|---|
| committer | Michal Idziorek <m.i@gmx.at> | 2015-05-14 10:44:00 +0200 |
| commit | dc7bf2f47d6f97407e3b50ae0b8ab59fd51079e5 (patch) | |
| tree | 1ed444c804d9ff55e23a7a007275c3d5c649a455 /xxx/boot2/GDT.asm | |
| parent | 7df4060ae807dd27f3ae0a11f243897f36053ba1 (diff) | |
moving unused files folder
Diffstat (limited to 'xxx/boot2/GDT.asm')
| -rw-r--r-- | xxx/boot2/GDT.asm | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/xxx/boot2/GDT.asm b/xxx/boot2/GDT.asm new file mode 100644 index 0000000..4c14b46 --- /dev/null +++ b/xxx/boot2/GDT.asm @@ -0,0 +1,77 @@ +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;;;;;;; Miguel's FoolOS Helper Functions ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +; +; Global Descriptor Table +; we have the null descriptor and a code and data block for a start +; +; 0x80 code segment +; 0x10 data segment +; +; this file contains pure data +; +; +; +; +global gdt_descriptor + +gdt_start: + +gdt_null: ;null descriptor (2 x 4 bytes) + dd 0x0 + dd 0x0 + +gdt_code: + ; flags: + ; present: 1 / privilege: 00 / type: 1 + ; code: 1 / conforming: 0 / readable: 1 / accessed: 0 + ; granularity: 1 / 16-bit default: 1 / 64-bit seg: 0 / AVL: 0 + dw 0xffff ;limit + dw 0x0 ;base + db 0x0 ;base + db 10011010b ;flags + db 11001111b ;flags & seg.limit + db 0x0 ;base + +gdt_data: + ; flags: + ; code: 0 / expand down: 0 / writable: 1 / accessed: 0 + dw 0xffff + dw 0x0 + db 0x0 + db 10010010b + db 11001111b + db 0x0 + +gdt16_code: + ; flags: + ; present: 1 / privilege: 00 / type: 1 + ; code: 1 / conforming: 0 / readable: 1 / accessed: 0 + ; granularity: 1 / 16-bit default: 1 / 64-bit seg: 0 / AVL: 0 + dw 0xffff ;limit + dw 0x0 ;base + db 0x0 ;base + db 10011010b ;flags + db 10001111b ;flags & seg.limit + db 0x0 ;base + +gdt16_data: + ; flags: + ; code: 0 / expand down: 0 / writable: 1 / accessed: 0 + dw 0xffff + dw 0x0 + db 0x0 + db 10010010b + db 10001111b + db 0x0 + +gdt_end: + +gdt_descriptor: + dw gdt_end-gdt_start-1 + dd gdt_start + +CODE_SEG equ gdt_code - gdt_start +DATA_SEG equ gdt_data - gdt_start +CODE16_SEG equ gdt16_code - gdt_start +DATA16_SEG equ gdt16_data - gdt_start |