diff --git a/04_day/bootpack.c b/04_day/bootpack.c
index 2e5f40d..cda3b75 100644
--- a/04_day/bootpack.c
+++ b/04_day/bootpack.c
@@ -1,12 +1,14 @@
 void io_hlt(void);
-void write_mem8(int addr, int data);
 
 void HariMain(void)
 {
-	int i; /* 声明变量，i是32位整数 */
+	int i; /* 声明变量i，i是32位整数 */
+	char *p; /* 声明变量p、用于BYTE [...]地址 */
 
 	for (i = 0xa0000; i <= 0xaffff; i++) {
-		write_mem8(i, i & 0x0f);
+		p = (char *)i;
+		*p = i & 0x0f;
+		/* 替代write_mem8(i, i & 0x0f); */
 	}
 
 	for (;;) {
diff --git a/04_day/naskfunc.nas b/04_day/naskfunc.nas
index d02201d..c7022eb 100644
--- a/04_day/naskfunc.nas
+++ b/04_day/naskfunc.nas
@@ -6,16 +6,10 @@
 [BITS 32]						; 3制作32位模式用的机器语言
 [FILE "naskfunc.nas"]			; 文件名
 
-		GLOBAL	_io_hlt,_write_mem8
+		GLOBAL	_io_hlt
 
 [SECTION .text]
 
 _io_hlt:	; void io_hlt(void);
 		HLT
 		RET
-
-_write_mem8:	; void write_mem8(int addr, int data);
-		MOV		ECX,[ESP+4]		; [ESP+4]中存放的是地址，将其读入ECX
-		MOV		AL,[ESP+8]		; [ESP+8]中存放的是数据，将其读入AL
-		MOV		[ECX],AL
-		RET