From d85b6209f37b4d886f9e85fd9592c9d7cf25deb9 Mon Sep 17 00:00:00 2001
From: Michal Idziorek <m.i@gmx.at>
Date: Wed, 27 Aug 2014 15:56:52 +0200
Subject: further cleanup of bootloader

---
 boot/vesa_setup_16.asm | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 boot/vesa_setup_16.asm

(limited to 'boot/vesa_setup_16.asm')

diff --git a/boot/vesa_setup_16.asm b/boot/vesa_setup_16.asm
new file mode 100644
index 0000000..4f276b5
--- /dev/null
+++ b/boot/vesa_setup_16.asm
@@ -0,0 +1,47 @@
+VesaSetup:
+    
+    pusha
+
+    ;VESA: get all available vesa modes!
+    mov ax,0	; set target address in es:di (0:offset)
+    mov es,ax
+    mov di,VESA_MODES
+    mov ax,0x4f00   ;vesa function: Get Controller Info
+    int 0x10	; call the interrupt to get the data from the bios!
+    vesa_err:
+    mov bx, VESA_CHECK1
+    call print_string
+    cmp ax,0x004f
+    je vesa_ok
+    jmp vesa_err
+    vesa_ok:
+    ;
+
+    ;VESA: get vesa info on mode of interest
+    mov ax,0	; set target address in es:di (0:offset)
+    mov es,ax
+    mov di,VESA_MODE_INFO
+    mov ax,0x4f01   ;vesa function: Get Mode Info
+    mov cx,VESA_MODE_SELECT   
+    int 0x10	; call the interrupt to get the data from the bios!
+    vesa_err2:
+    mov bx, VESA_CHECK2
+    call print_string
+    cmp ax,0x004f
+    je vesa_ok2
+    jmp vesa_err2
+    vesa_ok2:
+
+    ;VESA: finally switch to the mode of choice!
+    mov ax,0x4f02   ;vesa function: Set Mode
+    mov bx,VESA_MODE_SELECT 
+    int 0x10
+    vesa_err3:
+    mov bx, VESA_CHECK3
+    call print_string
+    cmp ax,0x004f
+    je vesa_ok3
+    jmp vesa_err3
+    vesa_ok3:
+    popa
+    ret
-- 
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