diff options
| author | Michal Idziorek <m.i@gmx.at> | 2015-05-13 16:18:24 +0200 |
|---|---|---|
| committer | Michal Idziorek <m.i@gmx.at> | 2015-05-13 16:18:24 +0200 |
| commit | 9a60edf72a3112adae4a914134da1adaf472ad5d (patch) | |
| tree | 64fe18ef416160244ad7dc80875e9f5a47390971 /asm/GDT.asm | |
| parent | 39d0c5ad74f69ef368d6f83e4eac575e76060eb4 (diff) | |
fixing gdt and interrupts
Diffstat (limited to 'asm/GDT.asm')
| -rw-r--r-- | asm/GDT.asm | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/asm/GDT.asm b/asm/GDT.asm new file mode 100644 index 0000000..f271377 --- /dev/null +++ b/asm/GDT.asm @@ -0,0 +1,78 @@ +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;;;;;;; Miguel's FoolOS Helper Functions ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +; +; Global Descriptor Table +; we have the null descriptor and a code and data block for a start +; +; 0x08 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 |