1 files changed, 38 insertions, 0 deletions
diff --git a/src/threads/loader.h b/src/threads/loader.h
new file mode 100644
index 0000000..5bd9813
--- /dev/null
+++ b/src/threads/loader.h
@@ -0,0 +1,38 @@
+#ifndef THREADS_LOADER_H
+#define THREADS_LOADER_H
+
+/* Constants fixed by the PC BIOS. */
+#define LOADER_BASE 0x7c00      /* Physical address of loader's base. */
+#define LOADER_END  0x7e00      /* Physical address of end of loader. */
+
+/* Physical address of kernel base. */
+#define LOADER_KERN_BASE 0x100000       /* 1 MB. */
+
+/* Kernel virtual address at which all physical memory is mapped.
+
+   The loader maps the 4 MB at the bottom of physical memory to
+   this virtual base address.  Later, paging_init() adds the rest
+   of physical memory to the mapping.
+
+   This must be aligned on a 4 MB boundary. */
+#define LOADER_PHYS_BASE 0xc0000000     /* 3 GB. */
+
+/* Important loader physical addresses. */
+#define LOADER_SIG (LOADER_END - LOADER_SIG_LEN)   /* 0xaa55 BIOS signature. */
+#define LOADER_ARGS (LOADER_SIG - LOADER_ARGS_LEN)     /* Command-line args. */
+#define LOADER_ARG_CNT (LOADER_ARGS - LOADER_ARG_CNT_LEN) /* Number of args. */
+#define LOADER_RAM_PGS (LOADER_ARG_CNT - LOADER_RAM_PGS_LEN) /* # RAM pages. */
+
+/* Sizes of loader data structures. */
+#define LOADER_SIG_LEN 2
+#define LOADER_ARGS_LEN 128
+#define LOADER_ARG_CNT_LEN 4
+#define LOADER_RAM_PGS_LEN 4
+
+/* GDT selectors defined by loader.
+   More selectors are defined by userprog/gdt.h. */
+#define SEL_NULL        0x00    /* Null selector. */
+#define SEL_KCSEG       0x08    /* Kernel code selector. */
+#define SEL_KDSEG       0x10    /* Kernel data selector. */
+
+#endif /* threads/loader.h */