arch/x86_64-pc/bootstrap/vesa.c

   1 #define _IMPLEMENTATION_
   2
   3 asm ("begin:");
   4
   5 #include "vesa.h"
   6 #define ABS(x) (((x) >= 0) ? (x) : -(x))
   7
   8 asm (".long getControllerInfo");
   9 asm (".long getModeInfo");
  10 asm (".long findMode");
  11 asm (".long setVbeMode");
  12 asm (".long controllerinfo");
  13 asm (".long modeinfo");
  14
  15 static void memcpy(char *from, char *to, int size)
  16 {
  17     while (size--)
  18         *to++ = *from++;
  19 }
  20
  21 short getControllerInfo(struct vbe_controller *info)
  22 {
  23     short retval;
  24     asm volatile("call go16 \n\t.code16 \n\t"
  25                 "movw $0x4f00, %%ax\n\t"
  26                 "int $0x10\n\t"
  27                 "movw %%ax, %0\n\t"
  28                 "DATA32 call go32\n\t.code32\n\t":"=b"(retval):"D"(&controllerinfo):"eax","ecx","cc");
  29     memcpy(&controllerinfo, info, sizeof(struct vbe_controller));
  30     return retval;
  31 }
  32
  33 short getModeInfo(long mode, struct vbe_mode *info)
  34 {
  35     short retval;
  36     asm volatile("call go16 \n\t.code16 \n\t"
  37                 "movw $0x4f01, %%ax\n\t"
  38                 "int $0x10\n\t"
  39                 "movw %%ax, %0\n\t"
  40                 "DATA32 call go32\n\t.code32\n\t":"=b"(retval):"c"(mode),"D"(&modeinfo):"eax","cc");
  41     memcpy(&modeinfo, info, sizeof(struct vbe_mode));
  42     return retval;
  43 }
  44
  45 short setVbeMode(long mode)
  46 {
  47     short retval;
  48     asm volatile("call go16 \n\t.code16 \n\t"
  49                 "movw $0x4f02, %%ax\n\t"
  50                 "int $0x10\n\t"
  51                 "movw %%ax, %0\n\t"
  52                 "DATA32 call go32\n\t.code32\n\t":"=b"(retval):"0"(mode & 0xf7ff):"eax","ecx","cc");
  53     return retval;
  54 }
  55
  56 short findMode(int x, int y, int d)
  57 {
  58     unsigned long match, bestmatch = ABS(640*480 - x*y);
  59     unsigned long matchd, bestmatchd = 15 >= d ? 15 - d : (d - 15) * 2;
  60     unsigned short bestmode = 0x110;
  61
  62     if (getControllerInfo(&controllerinfo) == 0x4f)
  63     {
  64         unsigned short *modes = (unsigned short *)
  65             (((controllerinfo.video_mode & 0xffff0000) >> 12) + (controllerinfo.video_mode & 0xffff));
  66
  67         int i;
  68
  69         for (i=0; modes[i] != 0xffff; ++i)
  70         {
  71             if (getModeInfo(modes[i], &modeinfo)!= 0x4f) continue;
  72             if ((modeinfo.mode_attributes & 0x90) != 0x90) continue;
  73             if (modeinfo.memory_model != 6) continue;
  74
  75             if (modeinfo.x_resolution == x &&
  76                 modeinfo.y_resolution == y &&
  77                 modeinfo.bits_per_pixel == d)
  78                 return modes[i];
  79
  80             match = ABS(modeinfo.x_resolution*modeinfo.y_resolution - x*y);
  81             matchd = modeinfo.bits_per_pixel >= d ? modeinfo.bits_per_pixel-d: (d-modeinfo.bits_per_pixel)*2;
  82             if (match < bestmatch || (match == bestmatch && matchd < bestmatchd))
  83             {
  84                 bestmode = modes[i];
  85                 bestmatch = match;
  86                 bestmatchd = matchd;
  87             }
  88         }
  89     }
  90     return bestmode;
  91 }
  92
  93 asm(
  94 "               .code16\n\t.globl go32\n\t.type go32,@function\n"
  95 "go32:          DATA32 ADDR32 lgdt GDT_reg\n"
  96 "               movl %cr0, %eax\n"
  97 "               bts $0, %eax\n"
  98 "               movl %eax, %cr0\n"
  99 "               ljmp $0x08, $1f\n"
 100 "               .code32\n"
 101 "1:             movw $0x10, %ax\n"
 102 "               movw %ax, %ds\n"
 103 "               movw %ax, %es\n"
 104 "               movw %ax, %fs\n"
 105 "               movw %ax, %gs\n"
 106 "               movw %ax, %ss\n"
 107 "               movl (%esp), %ecx\n"
 108 "               movl stack32, %eax\n"
 109 "               movl %eax, %esp\n"
 110 "               movl %eax, %ebp\n"
 111 "               movl %ecx, (%esp)\n"
 112 "               xorl %eax, %eax\n"
 113 "               ret\n"
 114 "\n"
 115 "               .code32\n\t.globl go16\n\t.type go16,@function\n"
 116 "go16:          lgdt GDT_reg\n"
 117 "               movl %esp, stack32\n"
 118 "               movl (%esp), %eax\n"
 119 "               movl %eax, begin + 0xff8\n"
 120 "               movl $begin + 0xff8, %esp\n"
 121 "               movl %esp, %ebp\n"
 122 "               movw $0x20, %ax\n"
 123 "               movw %ax, %ds\n"
 124 "               movw %ax, %es\n"
 125 "               movw %ax, %fs\n"
 126 "               movw %ax, %gs\n"
 127 "               movw %ax, %ss\n"
 128 "               ljmp $0x18, $1f\n\t.code16\n"
 129 "1:\n"
 130 "               movl %cr0, %eax\n"
 131 "               btc $0, %eax\n"
 132 "               movl %eax, %cr0\n"
 133 "               DATA32 ljmp $0x00, $1f\n"
 134 "1:\n"
 135 "               xorl %eax,%eax\n"
 136 "               movw %ax, %ds\n"
 137 "               movw %ax, %es\n"
 138 "               movw %ax, %fs\n"
 139 "               movw %ax, %gs\n"
 140 "               movw %ax, %ss\n"
 141 "               DATA32 ret\n"
 142 ".code32");
 143
 144 const unsigned long long GDT_Table[] = {
 145     0x0000000000000000ULL,
 146     0x00cf9a000000ffffULL,     /* Code32 */
 147     0x00cf92000000ffffULL,     /* Data32 */
 148     0x00009e000000ffffULL,     /* Code16 */
 149     0x000092000000ffffULL      /* Data16 */
 150 };
 151
 152 const struct
 153 {
 154     unsigned short l1 __attribute__((packed));
 155     const void *l3 __attribute__((packed));
 156 }
 157 GDT_reg = {sizeof(GDT_Table)-1, GDT_Table};
 158
 159 unsigned long           stack32;
 160 struct vbe_controller   controllerinfo;
 161 struct vbe_mode         modeinfo;