basic os stuff

kmain.c

@@ -0,0 +1,79 @@
+#define BUF_SIZE 64
+#define HEAP_SIZE 8192
+static char heap[HEAP_SIZE];
+static int  heap_top = 0;
+
+void* kmalloc(int size) {
+    void* ptr;
+    if (heap_top + size > HEAP_SIZE) return 0;
+    ptr = &heap[heap_top];
+    heap_top += size;
+    return ptr;
+}
+void print_char(char c);
+char get_char(void);
+int  check_key(void);
+void set_cursor(void);
+void set_cursor_pos(char row, char col);
+int get_cursor_pos();
+int str_eq(char* a, char* b) {
+      int i = 0;
+      while (a[i] && b[i]) {
+          if (a[i] != b[i]) return 0;
+          i++;
+      }
+      return a[i] == b[i];
+  }
+void print_string(char* str){
+    int i = 0;
+    while (str[i] != '\0'){
+        print_char(str[i]);
+        i++;
+    }
+}
+void print_hex(unsigned int n) {
+      char hex[] = "0x0000";
+      int i;
+      int nibble;
+      for (i = 5; i >= 2; i--) {
+          nibble = n & 0xF;
+          hex[i] = nibble < 10 ? '0' + nibble : 'A' + nibble - 10;
+          n >>= 4;
+      }
+      print_string(hex);
+  }
+
+
+ void read_line(char* buf) {
+     int i = 0;
+     char c;
+     while (i < BUF_SIZE - 1) {
+         c = get_char();
+         if (c == '\r') break;        /* Enter */
+         if (c == '\b' && i > 0) {   /* Backspace */
+             i--;
+             print_char('\b');
+             print_char(' ');
+             print_char('\b');
+         } else {
+             buf[i++] = c;
+             print_char(c);           /* echo */
+         }
+     }
+     buf[i] = '\0';
+ }
+ void kmain(void) {
+      char buf[BUF_SIZE];
+      set_cursor();
+      print_string("senkOS> ");
+      while (1) {
+          read_line(buf);
+          print_char('\n');
+          if (str_eq(buf, "hello")) {
+              print_string("world\n");
+          } else {
+              print_string("unknown command\n");
+          }
+          print_string("senkOS> ");
+      }
+  }