First successful VESA attempt

4 files changed, 181 insertions, 107 deletions

diff --git a/src/kernel/graphics/graphics.h b/src/kernel/graphics/graphics.h
index a9ed917..aa9440a 100644
--- a/src/kernel/graphics/graphics.h
+++ b/src/kernel/graphics/graphics.h
@@ -3,7 +3,9 @@
 
 #include <stddef.h>
 #include <stdint.h>
+#include "vesa.h"
 
+// VGA
 enum vga_color;
 
 void terminal_initialize(void);
@@ -18,4 +20,9 @@ void terminal_put_char(char c);
 
 void terminal_write_line(const char *data);
 
+// VESA/VBE
+void init_graphics();
+
+struct vbe_best best;
+
 #endif
\ No newline at end of file
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
\ No newline at end of file
diff --git a/src/kernel/graphics/vesa.c b/src/kernel/graphics/vesa.c
new file mode 100644
index 0000000..3549d66
--- /dev/null
+++ b/src/kernel/graphics/vesa.c
@@ -0,0 +1,11 @@
+#include "vesa.h"
+
+extern struct vbe_best vbe_find_mode();
+
+extern void vbe_set_mode(struct vbe_best);
+
+struct vbe_best best;
+
+void init_graphics() {
+    best = vbe_find_mode();
+}
\ No newline at end of file
diff --git a/src/kernel/graphics/vesa.h b/src/kernel/graphics/vesa.h
new file mode 100644
index 0000000..9023029
--- /dev/null
+++ b/src/kernel/graphics/vesa.h
@@ -0,0 +1,70 @@
+#ifndef MELVIX_VESA_H
+#define MELVIX_VESA_H
+
+#include <stdint.h>
+
+struct vbe_best {
+    uint8_t bpp;
+    uint16_t height;
+    uint16_t width;
+    uint32_t framebuffer;
+    uint32_t bytes_per_line;
+    uint32_t bytes_per_pixel;
+    uint32_t x_cur_max;
+    uint32_t y_cur_max;
+} __attribute__ ((packed));
+
+struct vbe_info {
+    char signature[4];    // must be "VESA" to indicate valid VBE support
+    uint16_t version;            // VBE version; high byte is major version, low byte is minor version
+    uint32_t oem;            // segment:offset pointer to OEM
+    uint32_t capabilities;        // bitfield that describes card capabilities
+    uint32_t video_modes;        // segment:offset pointer to list of supported video modes
+    uint16_t video_memory;        // amount of video memory in 64KB blocks
+    uint16_t software_rev;        // software revision
+    uint32_t vendor;            // segment:offset to card vendor string
+    uint32_t product_name;        // segment:offset to card model name
+    uint32_t product_rev;        // segment:offset pointer to product revision
+    char reserved[222];        // reserved for future expansion
+    char oem_data[256];        // OEM BIOSes store their strings in this area
+} __attribute__ ((packed));
+
+struct vbe_mode_info {
+    uint16_t attributes;        // deprecated, only bit 7 should be of interest to you, and it indicates the mode supports a linear frame buffer.
+    uint8_t window_a;            // deprecated
+    uint8_t window_b;            // deprecated
+    uint16_t granularity;        // deprecated; used while calculating bank numbers
+    uint16_t window_size;
+    uint16_t segment_a;
+    uint16_t segment_b;
+    uint32_t win_func_ptr;        // deprecated; used to switch banks from protected mode without returning to real mode
+    uint16_t pitch;            // number of bytes per horizontal line
+    uint16_t width;            // width in pixels
+    uint16_t height;            // height in pixels
+    uint8_t w_char;            // unused...
+    uint8_t y_char;            // ...
+    uint8_t planes;
+    uint8_t bpp;            // bits per pixel in this mode
+    uint8_t banks;            // deprecated; total number of banks in this mode
+    uint8_t memory_model;
+    uint8_t bank_size;        // deprecated; size of a bank, almost always 64 KB but may be 16 KB...
+    uint8_t image_pages;
+    uint8_t reserved0;
+
+    uint8_t red_mask;
+    uint8_t red_position;
+    uint8_t green_mask;
+    uint8_t green_position;
+    uint8_t blue_mask;
+    uint8_t blue_position;
+    uint8_t reserved_mask;
+    uint8_t reserved_position;
+    uint8_t direct_color_attributes;
+
+    uint32_t framebuffer;        // physical address of the linear frame buffer; write here to draw to the screen
+    uint32_t off_screen_mem_off;
+    uint16_t off_screen_mem_size;    // size of memory in the framebuffer but not being displayed on the screen
+    uint8_t reserved1[206];
+} __attribute__ ((packed));
+
+#endif