Fix PAGE_ENTRY_WRITABLE and PAGE_ENTRY_USER_ACCESSIBLE definitions, which were previously swapped.

Assign default values to the three graphicsX globals in Display_HAL.c
Remove MODE_TYPE define and use variables specifically for text mode instead of giving graphics defines text-based values. Conditionally use the appropriate defines in multiboot.h. NOTE: Using GRUB with text mode has regressed and these changes are meant to help marginally, but fixing text-mode is a low-priority.

Author: tthomps

MyOS_1/Graphics/Display_HAL.c

@@ -8,9 +8,9 @@
 bool graphicsPresent = false;
 bool textMode = true;
 uint32_t *linearFrameBuffer = NULL;
-unsigned int graphicsBpp;
-unsigned int graphicsWidth;
-unsigned int graphicsHeight;
+unsigned int graphicsBpp = 32;
+unsigned int graphicsWidth = GRAPHICS_WIDTH;
+unsigned int graphicsHeight = GRAPHICS_HEIGHT;
 
 // TODO: Create HAL interface and tie Bochs_VGA into it
 

MyOS_1/main.c

@@ -259,10 +259,17 @@ MULTIBOOT_INFO _MultibootInfo =
     // GRUB doesn't actually copy the kernel there, so we need to do some math
     // to find the actual address of KeStartup.
     (uint32_t)KeStartup - (uint32_t)NonPagingAddressOffset,
-    (uint32_t)MODE_TYPE,
+#if GRUB_GRAPHICS
+    (uint32_t)GRAPHICS_MODE,
     (uint32_t)GRAPHICS_WIDTH,
     (uint32_t)GRAPHICS_HEIGHT,
     (uint32_t)GRAPHICS_DEPTH
+#else
+    (uint32_t)TEXT_MODE,
+    (uint32_t)TEXT_WIDTH,
+    (uint32_t)TEXT_HEIGHT,
+    (uint32_t)TEXT_DEPTH    
+#endif
 };
 
 #pragma comment(linker, "/merge:.text=.a")

MyOS_1/multiboot.h

@@ -320,17 +320,19 @@ BASE_ADDRESS 0xC0000000
 #define STACK_SIZE                    0x4000   
 #define CHECKSUM                      -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
 
-#define GRAPHICS_MODE                 0
-#define TEXT_MODE                     1
-#define FLIP_MODE                     "Love Em"
-/*#define MODE_TYPE                     TEXT_MODE
-#define GRAPHICS_WIDTH                80
-#define GRAPHICS_HEIGHT               25
-#define GRAPHICS_DEPTH                0*/
-#define MODE_TYPE                     GRAPHICS_MODE
-#define GRAPHICS_WIDTH                800
-#define GRAPHICS_HEIGHT               600
-#define GRAPHICS_DEPTH                32
+#define GRUB_GRAPHICS               1 /* set to 1 to request GRUB to setup graphics, 0 for text-mode display (not working)*/
+#define GRAPHICS_MODE               0
+#define TEXT_MODE                   1
+#define FLIP_MODE                   "Love Em"
+
+// TODO: Text mode has regressed when booting with GRUB (see paging.h), but I don't think we really need it
+#define TEXT_WIDTH                  80
+#define TEXT_HEIGHT                 25
+#define TEXT_DEPTH                  0
+
+#define GRAPHICS_WIDTH              800
+#define GRAPHICS_HEIGHT             600
+#define GRAPHICS_DEPTH              32
 
 #endif /* ! ASM_FILE */
 

MyOS_1/paging.h

@@ -10,8 +10,8 @@ typedef /*__declspec(align(4096))*/ uint32_t PAGE_DIRECTORY_ENTRY;
 typedef /*__declspec(align(4096))*/ uint32_t PAGE_TABLE_ENTRY;
 
 #define PAGE_ENTRY_PRESENT          1
-#define PAGE_ENTRY_USER_ACCESSIBLE  2
-#define PAGE_ENTRY_WRITABLE         4
+#define PAGE_ENTRY_WRITABLE         2
+#define PAGE_ENTRY_USER_ACCESSIBLE  4
 
 #define DIRECTORY_ENTRY_PRESENT          1
 #define DIRECTORY_ENTRY_WRITABLE         2
@@ -85,6 +85,8 @@ inline void Paging_Enable(multiboot_info *multibootInfo)
     // TEMPTEMP HACKHACK! - identity map the linear frame buffer, which on my Qemu starts at 0xFD00 0000
     uint32_t lfbAddress = 0xFD000000;
 
+// TODO: This section of code will bug out if GRUB_GRAPHICS isn't defined in VirtualBox
+// TODO: We can conditionally comment this out, but then the gfx command fails to switch modes properly
     // see if Grub gave us an lfb address and use that one if it did
     if (multibootInfo->flags &  MULTIBOOT_INFO_FRAMEBUFFER_INFO)
     {
@@ -98,6 +100,7 @@ inline void Paging_Enable(multiboot_info *multibootInfo)
     {
         videoIdentityTable[i] = (lfbAddress + i * 0x1000) | PAGE_ENTRY_PRESENT | PAGE_ENTRY_WRITABLE;   // attributes: supervisor level, read/write, present
     }
+// End buggy section
 
     // put the lfb page table in the page directory
     uint32_t page = lfbAddress / 0x400000;