boot-111.1.tar.gz

[apple/boot.git] / i386 / libsaio / table.c

diff --git a/i386/libsaio/table.c b/i386/libsaio/table.c
index aa5c40eda527ea105d7a07d9f42ed55260f1c1e3..35d211701d364b24c3ccdb669f5712d100824434 100644 (file)
--- a/i386/libsaio/table.c
+++ b/i386/libsaio/table.c
@@ -46,9 +46,6 @@
  
 #include "memory.h"
 
-#define NGDTENT                6
-#define GDTLIMIT       48      /* NGDTENT * 8 */
-
 /*  Segment Descriptor
  *
  * 31          24         19   16                 7           0
@@ -64,23 +61,39 @@
  */
 
 struct seg_desc {
-       unsigned short  limit_15_0;
-       unsigned short  base_15_0;
-       unsigned char   base_23_16;
-       unsigned char   bit_15_8;
-       unsigned char   bit_23_16;
-       unsigned char   base_31_24;
-       };
+    unsigned short  limit_15_0;
+    unsigned short  base_15_0;
+    unsigned char   base_23_16;
+    unsigned char   bit_15_8;
+    unsigned char   bit_23_16;
+    unsigned char   base_31_24;
+};
 
+struct seg_desc Gdt[ NGDTENT ] = {
+    /*  0x0 : null */
+    {0x0000, 0x0000,  0x00, 0x00, 0x00, 0x00},
 
-struct seg_desc        Gdt[NGDTENT] = {
-    {0x0,    0x0,     0x0, 0x0,  0x0,  0x0},    /*  0x0 : null */
-    // byte granularity, 1Mb limit, MEMBASE offset
-    {0xFFFF, MEMBASE, 0x0, 0x9E, 0x4F, 0x0},    /*  0x8 : boot code */
-    // dword granularity, 2Gb limit, MEMBASE offset
-    {0xFFFF, MEMBASE, 0x0, 0x92, 0xCF, 0x0},    /* 0x10 : boot data */
-    {0xFFFF, MEMBASE, 0x0, 0x9E, 0xF,  0x0},    /* 0x18 : boot code, 16 bits */
-    {0xFFFF, 0x0,     0x0, 0x92, 0xCF, 0x0},    /* 0x20 : init data */
-    {0xFFFF, 0x0,     0x0, 0x9E, 0xCF, 0x0}     /* 0x28 : init code */
-};
+    /*  0x8 : boot protected mode 32-bit code segment
+              byte granularity, 1MB limit, MEMBASE offset */
+    {0xFFFF, MEMBASE, 0x00, 0x9E, 0x4F, 0x00},    
+    
+    /* 0x10 : boot protected mode data segment
+              page granularity, 4GB limit, MEMBASE offset */
+    {0xFFFF, MEMBASE, 0x00, 0x92, 0xCF, 0x00},
+
+    /* 0x18 : boot protected mode 16-bit code segment
+              byte granularity, 1MB limit, MEMBASE offset */
+    {0xFFFF, MEMBASE, 0x00, 0x9E, 0x0F, 0x00},
 
+    /* 0x20 : kernel init 32-bit data segment
+              page granularity, 4GB limit, zero offset */
+    {0xFFFF, 0x0000,  0x00, 0x92, 0xCF, 0x00},
+
+    /* 0x28 : kernel init 32-bit code segment
+              page granularity, 4GB limit, zero offset */
+    {0xFFFF, 0x0000,  0x00, 0x9E, 0xCF, 0x00},
+
+    /* 0x30 : boot real mode data/stack segment
+              byte granularity, 64K limit, MEMBASE offset, expand-up */
+    {0xFFFF, MEMBASE, 0x00, 0x92, 0x00, 0x00},    
+};