Added working support for segment:offset pointer

4 files changed, 80 insertions, 28 deletions

diff --git a/src/kernel/boot.asm b/src/kernel/boot.asm
index 7c7f5d9..197e13c 100644
--- a/src/kernel/boot.asm
+++ b/src/kernel/boot.asm
@@ -45,10 +45,6 @@ stublet:
 
 %include "src/kernel/interact.asm"
 
-vbe_init_structure:
-	.signature db "VBE2"
-	.table_data: resb 512-4
-
 ; Store the stack
 SECTION .bss
     resb 8192 ; Reserve 8KiB
diff --git a/src/kernel/graphics/vesa.c b/src/kernel/graphics/vesa.c
index 35e96c6..f3fd865 100644
--- a/src/kernel/graphics/vesa.c
+++ b/src/kernel/graphics/vesa.c
@@ -1,6 +1,5 @@
 #include "vesa.h"
 #include "graphics.h"
-#include "../lib/lib.h"
 #include "../input/input.h"
 #include "../system.h"
 
@@ -13,7 +12,7 @@ void switch_to_vga() {
     keyboard_install();
 }
 
-vbe_mode_info *vbe_set_mode(unsigned short mode) {
+struct vbe_mode_info *vbe_set_mode(unsigned short mode) {
     regs16_t regs;
     regs.ax = 0x4F02;
     regs.bx = mode | (1 << 14);
@@ -29,7 +28,7 @@ vbe_mode_info *vbe_set_mode(unsigned short mode) {
             switch_to_vga();
         }
 
-        vbe_mode_info *vbe_info = (vbe_mode_info *) 0xA0000;
+        struct vbe_mode_info *vbe_info = (struct vbe_mode_info *) 0xA0000;
 
         vbe_width = vbe_info->width;
         vbe_height = vbe_info->height;
@@ -52,31 +51,59 @@ vbe_mode_info *vbe_set_mode(unsigned short mode) {
         switch_to_vga();
     }
 
-    vbe_mode_info vbe_info;
+    struct vbe_mode_info vbe_info;
     return &vbe_info;
 }
 
 void set_optimal_resolution() {
-    extern vbe_info *vbe_init_structure;
+    init();
+    terminal_write_string("SUCCESS!\n");
+    keyboard_install();
+
+    struct vbe_info *info;
+    struct vbe_mode_info *mode_info;
+
+    info->signature[0] = 'V';
+    info->signature[1] = 'B';
+    info->signature[2] = 'E';
+    info->signature[3] = '2';
+
     regs16_t regs;
     regs.ax = 0x4F00;
-    regs.di = vbe_init_structure;
-    regs.es = 0xA000;
+    regs.es = get_segment(info);
+    regs.di = get_offset(info);
     int32(0x10, &regs);
 
     if (regs.ax != 0x004F) {
         switch_to_vga();
     }
 
-    vbe_info *vbe_modes = (vbe_info *) 0xA0000;
+    uint16_t *mode_ptr = get_ptr(info->video_modes);
+    uint16_t mode;
+    struct vbe_mode_info *highest;
+    while ((mode = *mode_ptr++) != 0xFFFF) {
+        mode &= 0x1FF;
+        regs16_t regs2;
+        regs2.ax = 0x4F01;
+        regs2.cx = mode;
+        regs2.es = get_segment(mode_info);
+        regs2.di = get_offset(mode_info);
+        int32(0x10, &regs2);
 
-    if (strcmp(vbe_modes->signature, "VESA") == 0) {
+        if ((mode_info->attributes & 0x90) != 0x90) continue;
+        if (mode_info->height >= highest->height) {
+            highest = mode_info;
+        }
+    }
+
+    /*if (strcmp((const char *) info->version, (const char *) 0x300) == 0) {
         init();
         terminal_write_string("SUCCESS!\n");
+        terminal_write_line((const char *) &info->vendor);
         keyboard_install();
     } else {
         init();
         terminal_write_string("FAILED!\n");
-        keyboard_install();
-    }
+        keyboard_install(); // Find out why commands only work when keyboard gets reinstalled after write
+    }*/
 }
\ No newline at end of file
diff --git a/src/kernel/graphics/vesa.h b/src/kernel/graphics/vesa.h
index 7458a47..203b06b 100644
--- a/src/kernel/graphics/vesa.h
+++ b/src/kernel/graphics/vesa.h
@@ -2,13 +2,14 @@
 #define MELVIX_VESA_H
 
 #include <stdint.h>
+#include "../system.h"
 
-typedef struct __attribute__ ((packed)) {
+struct vbe_info {
     char signature[4];
     uint32_t version;
     uint32_t oem;
     uint32_t capabilities;
-    uint32_t video_modes;
+    struct far_ptr video_modes;
     uint32_t video_memory;
     uint32_t software_rev;
     uint32_t vendor;
@@ -16,9 +17,9 @@ typedef struct __attribute__ ((packed)) {
     uint32_t product_rev;
     char reserved[222];
     char oem_data[256];
-} vbe_info;
+} __attribute__ ((packed));
 
-typedef struct __attribute__ ((packed)) {
+struct vbe_mode_info {
     uint16_t attributes;
     uint8_t window_a;
     uint8_t window_b;
@@ -54,19 +55,12 @@ typedef struct __attribute__ ((packed)) {
     uint32_t off_screen_mem_off;
     uint16_t off_screen_mem_size;
     uint8_t reserved1[206];
-} vbe_mode_info;
+} __attribute__ ((packed));
 
-vbe_mode_info *vbe_set_mode(unsigned short mode);
+struct vbe_mode_info *vbe_set_mode(unsigned short mode);
 
 void set_optimal_resolution();
 
-typedef struct __attribute__ ((packed)) {
-    unsigned short di, si, bp, sp, bx, dx, cx, ax;
-    unsigned short gs, fs, es, ds, eflags;
-} regs16_t;
-
-extern void int32(unsigned char intnum, regs16_t *regs);
-
 int vbe_current_mode;
 int vbe_width;
 int vbe_height;
diff --git a/src/kernel/system.h b/src/kernel/system.h
index 6044570..47d902c 100644
--- a/src/kernel/system.h
+++ b/src/kernel/system.h
@@ -3,4 +3,39 @@
 
 void init();
 
+typedef struct __attribute__ ((packed)) {
+    unsigned short di, si, bp, sp, bx, dx, cx, ax;
+    unsigned short gs, fs, es, ds, eflags;
+} regs16_t;
+
+extern void int32(unsigned char intnum, regs16_t *regs);
+
+struct far_ptr {
+    union {
+        uint32_t ptr;
+        struct {
+            uint16_t offset, segment;
+        };
+    };
+} __attribute__ ((packed));
+
+static inline uint16_t get_offset(const volatile void *p) {
+    return (uint16_t) (uintptr_t) p & 0x000F;
+}
+
+static inline uint16_t get_segment(const volatile void *p) {
+    return (uint16_t) (((uintptr_t) p) >> 4);
+}
+
+static inline struct far_ptr FAR_PTR(void *__ptr) {
+    struct far_ptr __fptr;
+    __fptr.offset = get_offset(__ptr);
+    __fptr.segment = get_segment(__ptr);
+    return __fptr;
+}
+
+static inline void *get_ptr(struct far_ptr fptr) {
+    return (void *) (unsigned long) ((fptr.segment << 4) + fptr.offset);
+}
+
 #endif