Define framebuffer video independently of VBE video

doc/boot.S

@@ -30,9 +30,9 @@
 
 /* The flags for the Multiboot header.  */
 #ifdef __ELF__
-# define MULTIBOOT_HEADER_FLAGS		0x00000003
+# define MULTIBOOT_HEADER_FLAGS		0x00000007
 #else
-# define MULTIBOOT_HEADER_FLAGS		0x00010003
+# define MULTIBOOT_HEADER_FLAGS		0x00010007
 #endif
 	
 	.text
@@ -64,7 +64,17 @@ multiboot_header:
 	.long	_end
 	/* entry_addr */
 	.long	multiboot_entry
-#endif /* ! __ELF__ */
+#else /* ! __ELF__ */
+	.long	0
+	.long	0
+	.long	0
+	.long	0
+	.long	0	
+#endif /* __ELF__ */
+	.long 0
+	.long 1024
+	.long 768
+	.long 32
 
 multiboot_entry:
 	/* Initialize the stack pointer.  */

doc/kernel.c

@@ -150,6 +150,87 @@ cmain (unsigned long magic, unsigned long addr)
 		mmap->len & 0xffffffff,
 		(unsigned) mmap->type);
     }
+
+  /* Draw diagonal blue line.  */
+  if (CHECK_FLAG (mbi->flags, 12))
+    {
+      multiboot_uint32_t color;
+      unsigned i;
+      void *fb = (void *) (unsigned long) mbi->framebuffer_addr;
+
+      switch (mbi->framebuffer_type)
+	{
+	case MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED:
+	  {
+	    unsigned best_distance, distance;
+	    struct multiboot_color *palette;
+	    
+	    palette = (struct multiboot_color *) mbi->framebuffer_palette_addr;
+
+	    color = 0;
+	    best_distance = 4*256*256;
+	    
+	    for (i = 0; i < mbi->framebuffer_palette_num_colors; i++)
+	      {
+		distance = (0xff - palette[i].blue) * (0xff - palette[i].blue)
+		  + palette[i].red * palette[i].red
+		  + palette[i].green * palette[i].green;
+		if (distance < best_distance)
+		  {
+		    color = i;
+		    best_distance = distance;
+		  }
+	      }
+	  }
+	  break;
+
+	case MULTIBOOT_FRAMEBUFFER_TYPE_RGB:
+	  color = ((1 << mbi->framebuffer_blue_mask_size) - 1) 
+	    << mbi->framebuffer_blue_field_position;
+	  break;
+
+	default:
+	  color = 0xffffffff;
+	  break;
+	}
+      for (i = 0; i < mbi->framebuffer_width
+	     && i < mbi->framebuffer_height; i++)
+	{
+	  switch (mbi->framebuffer_bpp)
+	    {
+	    case 8:
+	      {
+		multiboot_uint8_t *pixel = fb + mbi->framebuffer_pitch * i + i;
+		*pixel = color;
+	      }
+	      break;
+	    case 15:
+	    case 16:
+	      {
+		multiboot_uint16_t *pixel
+		  = fb + mbi->framebuffer_pitch * i + 2 * i;
+		*pixel = color;
+	      }
+	      break;
+	    case 24:
+	      {
+		multiboot_uint32_t *pixel
+		  = fb + mbi->framebuffer_pitch * i + 3 * i;
+		*pixel = (color & 0xffffff) | (*pixel & 0xff000000);
+	      }
+	      break;
+
+	    case 32:
+	      {
+		multiboot_uint32_t *pixel
+		  = fb + mbi->framebuffer_pitch * i + 4 * i;
+		*pixel = color;
+	      }
+	      break;
+	    }
+	}
+    }
+
 }    
 
 /* Clear the screen and initialize VIDEO, XPOS and YPOS.  */

doc/multiboot.h

@@ -32,7 +32,7 @@
 #define MULTIBOOT_BOOTLOADER_MAGIC		0x2BADB002
 
 /* The bits in the required part of flags field we don't support.  */
-#define MULTIBOOT_UNSUPPORTED			0x0000fffc
+#define MULTIBOOT_UNSUPPORTED                   0x0000fff8
 
 /* Alignment of multiboot modules.  */
 #define MULTIBOOT_MOD_ALIGN			0x00001000
@@ -88,10 +88,12 @@
 #define MULTIBOOT_INFO_APM_TABLE		0x00000400
 
 /* Is there video information?  */
-#define MULTIBOOT_INFO_VIDEO_INFO		0x00000800
+#define MULTIBOOT_INFO_VBE_INFO		        0x00000800
+#define MULTIBOOT_INFO_FRAMEBUFFER_INFO	        0x00001000
 
 #ifndef ASM_FILE
 
+typedef unsigned char		multiboot_uint8_t;
 typedef unsigned short		multiboot_uint16_t;
 typedef unsigned int		multiboot_uint32_t;
 typedef unsigned long long	multiboot_uint64_t;
@@ -190,9 +192,43 @@ struct multiboot_info
   multiboot_uint16_t vbe_interface_seg;
   multiboot_uint16_t vbe_interface_off;
   multiboot_uint16_t vbe_interface_len;
+
+  multiboot_uint64_t framebuffer_addr;
+  multiboot_uint32_t framebuffer_pitch;
+  multiboot_uint32_t framebuffer_width;
+  multiboot_uint32_t framebuffer_height;
+  multiboot_uint8_t framebuffer_bpp;
+  multiboot_uint8_t framebuffer_type;
+  union
+  {
+    struct
+    {
+      multiboot_uint32_t framebuffer_palette_addr;
+      multiboot_uint16_t framebuffer_palette_num_colors;
+    };
+    struct
+    {
+      multiboot_uint8_t framebuffer_red_field_position;
+      multiboot_uint8_t framebuffer_red_mask_size;
+      multiboot_uint8_t framebuffer_green_field_position;
+      multiboot_uint8_t framebuffer_green_mask_size;
+      multiboot_uint8_t framebuffer_blue_field_position;
+      multiboot_uint8_t framebuffer_blue_mask_size;
+    };
+  };
+};
+
+struct multiboot_color
+{
+  multiboot_uint8_t red;
+  multiboot_uint8_t green;
+  multiboot_uint8_t blue;
 };
 typedef struct multiboot_info multiboot_info_t;
 
+#define MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED 0
+#define MULTIBOOT_FRAMEBUFFER_TYPE_RGB     1
+
 struct multiboot_mmap_entry
 {
   multiboot_uint32_t size;

doc/multiboot.texi

@@ -638,6 +638,15 @@ follows:
 84      | vbe_interface_off |
 86      | vbe_interface_len |
         +-------------------+
+88      | framebuffer_addr  |    (present if flags[12] is set)
+96      | framebuffer_pitch |
+100     | framebuffer_width |
+104     | framebuffer_height|
+108     | framebuffer_bpp   |
+109     | framebuffer_type  |
+110-115 | color_info        |
+        +-------------------+
+
 @end group
 @end example
 
@@ -914,63 +923,15 @@ bytes, and the others are 2 bytes. See
 @uref{http://www.microsoft.com/hwdev/busbios/amp_12.htm, Advanced Power
 Management (APM) BIOS Interface Specification}, for more information.
 
-If bit 11 in the @samp{flags} is set, the graphics table is available.
+If bit 11 in the @samp{flags} is set, the @sc{vbe} table is available.
 
 The fields @samp{vbe_control_info} and @samp{vbe_mode_info} contain
 the physical addresses of @sc{vbe} control information returned by the
 @sc{vbe} Function 00h and @sc{vbe} mode information returned by the
-@sc{vbe} Function 01h, respectively. In case of non-@sc{vbe} video driver
+@sc{vbe} Function 01h, respectively.
-@samp{vbe_control_info} contains zero and @samp{vbe_mode_info} points to the
-following 256-byte structure:
-
-@example
-@group
-        +----------------------+
-0       | flags                |
-2       | zeros                |
-16      | pitch                |
-18      | width                |
-20      | height               |
-22      | zeros                |
-25      | bits per pixel       |
-26      | zeros                |
-27      | memory model         |
-28      | zeros                |
-31      | red mask size        |
-32      | red field position   |
-33      | green mask size      |
-34      | green field position |
-35      | blue mask size       |
-36      | blue field position  |
-37      | alpha mask size      |
-38      | alpha field position |
-39      | zero                 |
-40      | framebuffer address  |
-44      | zero                 |
-50      | pitch                |
-52      | zero                 |
-54      | red mask size        |
-55      | red field position   |
-56      | green mask size      |
-57      | green field position |
-58      | blue mask size       |
-59      | blue field position  |
-60      | alpha mask size      |
-61      | alpha field position |
-62      | zeros                |
-        +----------------------+
-@end group
-@end example
-
-All fields have the same meaning as the corresponding VBE mode info
-structure except fields marked as zeros which are zero-filled.
-
-If video is a linear framebuffer boot loader has to ensure that
-displayed region starts at offset @samp{0} of linear framebuffer. 
 
 The field @samp{vbe_mode} indicates current video mode in the format
-specified in @sc{vbe} 3.0. In case of non-@sc{vbe} video driver
+specified in @sc{vbe} 3.0.
-@samp{vbe_mode} contains 0xffff.
 
 The rest fields @samp{vbe_interface_seg}, @samp{vbe_interface_off}, and
 @samp{vbe_interface_len} contain the table of a protected mode interface
@@ -984,6 +945,42 @@ The fields for the graphics table are designed for @sc{vbe}, but
 Multiboot boot loaders may simulate @sc{vbe} on non-@sc{vbe} modes, as
 if they were @sc{vbe} modes.
 
+If bit 12 in the @samp{flags} is set, the @sc{Framebuffer} table is available.
+
+The field @samp{framebuffer_addr} contains framebuffer physical address. This field is 64-bit wide but bootloader @dfn{should} set it under 4GiB if possible for compatibility with payloads which aren't aware of PAE or amd64. The field @samp{framebuffer_pitch} contains pitch in bytes. The fields @samp{framebuffer_width}, @samp{framebuffer_height} contain framebuffer dimensions in pixels. The field @samp{framebuffer_bpp} contains number of bits per pixel. If @samp{framebuffer_type} is set to 0 it means indexed color. In this case color_info is defined as following:
+@example
+@group
+        +----------------------------------+
+110     | framebuffer_palette_addr         |
+114     | framebuffer_palette_num_colors   |
+        +----------------------------------+
+@end group
+@end example
+@samp{framebuffer_palette_addr} contains address of array of @samp{framebuffer_palette_num_colors} following structures:
+@example
+@group
+        +-------------+
+0       | red_value   |
+1       | green_value |
+2       | blue_value  |
+        +-------------+
+@end group
+@end example
+If @samp{framebuffer_type} is set to 1 it direct RGB color. Then color_type is defined as following:
+
+@example
+@group
+        +----------------------------------+
+110     | framebuffer_red_field_position   |
+111     | framebuffer_red_mask_size        |
+112     | framebuffer_green_field_position |
+113     | framebuffer_green_mask_size      |
+114     | framebuffer_blue_field_position  |
+115     | framebuffer_blue_mask_size       |
+        +----------------------------------+
+@end group
+@end example
+All further values of @samp{framebuffer_type} are reserved for future expansion
 
 @node Examples
 @chapter Examples