diff options
Diffstat (limited to 'src/kernel/graphics/vesa.asm')
| -rw-r--r-- | src/kernel/graphics/vesa.asm | 200 |
1 files changed, 93 insertions, 107 deletions
diff --git a/src/kernel/graphics/vesa.asm b/src/kernel/graphics/vesa.asm index 3fdd4cd..820d592 100644 --- a/src/kernel/graphics/vesa.asm +++ b/src/kernel/graphics/vesa.asm @@ -1,30 +1,34 @@ -width equ 1024 -height equ 768 -bpp equ 32 +global vbe_set_mode +global vbe_find_mode -search_video_mode: - [bits 16] +vbe_set_mode: + mov [width], ax + mov [height], bx + mov [bpp], cl - push es - mov ax, 0x4F00 - mov di, vbe_info_block - int 0x10 - pop es + sti - mov ax, word [vbe_info_block.video_modes] - mov [offset], ax - mov ax, word [vbe_info_block.video_modes+2] - mov [segments], ax + ; Get VBE BIOS info + push es + mov ax, 0x4F00 + mov di, [vbe_info] + int 0x10 + pop es - mov ax, [segments] - mov fs, ax - mov si, [offset] + ; Check if BIOS has VBE support + cmp ax, 0x4F + jne error - mov cx, 1 - push cx - ret + mov ax, word[vbe_info.video_modes] + mov [offset], ax + mov ax, word[vbe_info.video_modes+2] + mov [mode_segment], ax + + mov ax, [mode_segment] + mov fs, ax + mov si, [offset] -find_mode: +vbe_find_mode: mov dx, [fs:si] add si, 2 mov [offset], si @@ -32,105 +36,91 @@ find_mode: mov ax, 0 mov fs, ax + cmp [mode], word 0xFFFF + je error + + ; Get VBE mode info push es mov ax, 0x4F01 mov cx, [mode] - mov di, mode_info_block + mov di, [vbe_mode_info] int 0x10 pop es - cmp ax, 0x004F - - pop cx - cmp cx, 4 - je reset_counter - inc cx - push cx - -check_mode: - mov cx, 0 - mov bx, [best_video_mode.width] - cmp bx, [mode_info_block.width] - jl save_and_continue - je compare_height - jmp next_mode - -compare_height: - mov bx, [best_video_mode.height] - cmp bx, [mode_info_block.height] - jl save_and_continue - je compare_bpp - jmp next_mode - -compare_bpp: - mov dx, [best_video_mode.bpp] - mov ax, [mode_info_block.bpp] - and ax, 11111111b - cmp dx, ax - jl save_and_continue - jmp next_mode - -save_and_continue: - mov bx, [mode_info_block.width] - mov [best_video_mode.width], bx - - shr bx,3 - dec bx - mov [best_video_mode.x_cur_max], bx - - mov bx, [mode_info_block.height] - mov [best_video_mode.height], bx - - shr bx, 4 - dec bx - mov word [best_video_mode.y_cur_max], ax - - mov ebx, 0 - mov bl, [mode_info_block.bpp] - mov byte [best_video_mode.bpp], bl - shr ebx, 3 - mov dword [best_video_mode.bytes_per_pixel], ebx - - mov bx, [mode] - mov [best_video_mode.mode], bx - mov ebx,[mode_info_block.framebuffer] - mov dword [best_video_mode.framebuffer], ebx - mov bx, [mode_info_block.pitch] - mov word [best_video_mode.bytes_per_line], bx - jmp next_mode - pop es - jmp $ - -new_line_and_next_mode: - mov cx,1 - push cx - jmp next_mode - -reset_counter: - mov cx, 1 - push cx - jmp check_mode - -set_mode: + cmp ax, 0x4F + jne error + + mov ax, [width] + cmp ax, [vbe_mode_info.width] + jne next_mode + + mov ax, [height] + cmp ax, [vbe_mode_info.height] + jne next_mode + + mov al, [bpp] + cmp al, [vbe_mode_info.bpp] + jne next_mode + + ; Found best mode! + mov ax, [width] + mov word[vbe_best.width], ax + mov ax, [height] + mov word[vbe_best.height], ax + mov eax, [vbe_mode_info.framebuffer] + mov dword[vbe_best.framebuffer], eax + mov ax, [vbe_mode_info.pitch] + mov word[vbe_best.bytes_per_line], ax + mov eax, 0 + mov al, [bpp] + mov byte[vbe_best.bpp], al + shr eax, 3 + mov dword[vbe_best.bytes_per_pixel], eax + + mov ax, [width] + shr ax, 3 + dec ax + mov word[vbe_best.x_cur_max], ax + + mov ax, [height] + shr ax, 4 + dec ax + mov word[vbe_best.y_cur_max], ax + + ; Set the mode push es mov ax, 0x4F02 - mov bx, [best_video_mode.mode] + mov bx, [mode] or bx, 0x4000 mov di, 0 int 0x10 pop es cmp ax, 0x4F + jne error + clc + ret next_mode: - mov ax, [segments] + mov ax, [mode_segment] mov fs, ax mov si, [offset] - jmp find_mode + jmp vbe_find_mode -vbe_info_block: - .signature db "VBE2"; indicate support for VBE 2.0+ +error: + stc + ret + +width dw 0 +height dw 0 +bpp db 0 +mode_segment dw 0 +offset dw 0 +mode dw 0 + +vbe_info: + .signature db "VESA" .version dw 0 .oem dd 0 .capabilities dd 0 @@ -143,7 +133,7 @@ vbe_info_block: .reserved times 222 db 0 .oem_data times 256 db 0 -mode_info_block: +vbe_mode_info: .attributes dw 0 .window_a db 0 .window_b db 0 @@ -180,7 +170,7 @@ mode_info_block: .off_screen_mem_size dw 0 .reserved1 times 206 db 0 -best_video_mode: +vbe_best: .bpp db 0 .height dw 0 .width dw 0 @@ -189,8 +179,4 @@ best_video_mode: .bytes_per_line dw 0 .bytes_per_pixel dd 0 .x_cur_max dw 0 - .y_cur_max dw 0 - -segments dw 0 -offset dw 0 -mode dw 0 + .y_cur_max dw 0
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