+#define KSTACK_SIZE MEM_1MB
+#define KSTACK_START (USER_START - KSTACK_SIZE)
+#define KSTACK_TOP ((USER_START - 1) & ~0xf)
+
+#define KERNEL_MM_BASE 0xC0000000
+
+#define KCODE_MAX_SIZE MEM_4MB
+// #define KHEAP_START (KERNEL_MM_BASE + KCODE_MAX_SIZE)
+// #define KHEAP_SIZE_MB 256
+
+#define VGA_FRAMEBUFFER 0xB8000
+
+#define KCODE_SEG 0x08
+#define KDATA_SEG 0x10
+#define UCODE_SEG 0x1B
+#define UDATA_SEG 0x23
+#define TSS_SEG 0x28
+
+#define USTACK_SIZE MEM_4MB
+#define USTACK_TOP 0x9ffffff0
+#define USTACK_END (0x9fffffff - USTACK_SIZE + 1)
+#define UMMAP_START 0x4D000000
+#define UMMAP_END (USTACK_END - MEM_4MB)