Made kernel C++ now

2021-10-21 23:19:36 +01:00
parent cd8bd42ebb
commit 2a68860bef
14 changed files with 70 additions and 75 deletions
@@ -0,0 +1,72 @@
+#include "gdt.h"
+
+gdt_entry gdt[] = {
+  (gdt_entry){ // Null Segment
+    .limit_lo = 0,
+    .base_lo = 0,
+    .base_mid = 0,
+    .accessed = 0,
+    .read_write = 0,
+    .direction = 0,
+    .executable = 0,
+    .system_segment = 0,
+    .privilege = 0,
+    .present = 0,
+    .limit_hi = 0,
+    .__ignored__ = 0,
+    .size = 0,
+    .granularity = 0,
+    .base_hi = 0,
+  },
+  (gdt_entry){ // Code Segment
+    .limit_lo = 0xffff,
+    .base_lo = 0,
+    .base_mid = 0,
+    .accessed = 0,
+    .read_write = 1,
+    .direction = 0,
+    .executable = 1,
+    .system_segment = 1,
+    .privilege = 0,
+    .present = 1,
+    .limit_hi = 0xf,
+    .__ignored__ = 0,
+    .size = 1,
+    .granularity = 1,
+    .base_hi = 0
+  },
+  (gdt_entry){ // Data Segment
+    .limit_lo = 0xffff,
+    .base_lo = 0,
+    .base_mid = 0,
+    .accessed = 0,
+    .read_write = 1,
+    .direction = 0,
+    .executable = 0,
+    .system_segment = 1,
+    .privilege = 0,
+    .present = 1,
+    .limit_hi = 0xf,
+    .__ignored__ = 0,
+    .size = 1,
+    .granularity = 1,
+    .base_hi = 0
+  }
+};
+
+gdt_descr descr = (gdt_descr){
+  .size = sizeof(gdt) - 1,
+  .offset = gdt,
+};
+
+__attribute__((far)) void far_call() {}
+
+void init_gdt() {
+  asm volatile("lgdt %0;"
+               "mov $0x10, %%eax;"
+               "mov %%eax, %%ss;"
+               "mov $0x10, %%eax;"
+               "mov %%eax, %%ds" : : "m" (descr));
+  
+  far_call();
+}