diff -uNp bootload/Makefile bootload.m/Makefile
--- bootload/Makefile	Sun Feb 28 23:23:47 2010
+++ bootload.m/Makefile	Sat May  7 22:52:32 2011
@@ -20,7 +20,7 @@ H8WRITE = ../../tools/h8write/h8write
 H8WRITE_SERDEV = /dev/cuad0
 
 OBJS  = vector.o startup.o intr.o main.o interrupt.o
-OBJS += lib.o serial.o xmodem.o elf.o
+OBJS += lib.o serial.o xmodem.o elf.o monitor.o
 
 TARGET = kzload
 
diff -uNp bootload/main.c bootload.m/main.c
--- bootload/main.c	Sun Feb 28 23:23:47 2010
+++ bootload.m/main.c	Sat May  7 23:11:16 2011
@@ -2,6 +2,7 @@
 #include "interrupt.h"
 #include "serial.h"
 #include "xmodem.h"
+#include "monitor.h"
 #include "elf.h"
 #include "lib.h"
 
@@ -89,6 +90,8 @@ int main(void)
       putxval(size, 0);
       puts("\n");
       dump(loadbuf, size);
+    } else if (!strcmp(buf, "mon")) { /* 簡易モニタ起動 */
+      monitor_main();
     } else if (!strcmp(buf, "run")) { /* ELF形式ファイルの実行 */
       entry_point = elf_load(loadbuf); /* メモリ上に展開(ロード) */
       if (!entry_point) {
diff -uNp bootload/monitor.c bootload.m/monitor.c
--- bootload/monitor.c	Thu Jan  1 09:00:00 1970
+++ bootload.m/monitor.c	Tue May 10 20:53:39 2011
@@ -0,0 +1,453 @@
+/*
+	monitor.c
+
+	original code: SASANO Takayoshi
+	--- public domain, no warranty.
+*/
+#include "defines.h"
+#include "lib.h"
+
+typedef	unsigned long	uintptr_t;
+typedef	signed long	intptr_t;
+typedef	unsigned long	uint32_t;
+typedef	unsigned short	uint16_t;
+typedef	unsigned char	uint8_t;
+
+#define	putxA(v)	putxval((v), 8)
+#define	putx8(v)	putxval((v), 8)
+#define	putx4(v)	putxval((v), 4)
+#define	putx2(v)	putxval((v), 2)
+#define	putch(c)	putc(c)
+#define	putstr(str)	puts(str)
+#define	getstr(str)	gets(str)
+
+/* メモリ操作 */
+static	void		poke32(uintptr_t addr, uint32_t val)
+					{*(uint32_t *)(addr) = val;}
+static	void		poke16(uintptr_t addr, uint16_t val)
+					{*(uint16_t *)(addr) = val;}
+static	void		poke8(uintptr_t addr, uint8_t val)
+					{*(uint8_t *)(addr) = val;}
+static	uint32_t	peek32(uintptr_t addr)
+					{return *(uint32_t *)(addr);}
+static	uint16_t	peek16(uintptr_t addr)
+					{return *(uint16_t *)(addr);}
+static	uint8_t		peek8(uintptr_t addr)
+					{return *(uint8_t *)(addr);}
+
+/* I/O空間を持たない機種ではpoke/peekのエイリアスとする */
+#define	out32(addr, val)	poke32(addr, val)
+#define	out16(addr, val)	poke16(addr, val)
+#define	out8(addr, val)		poke8(addr, val)
+#define	in32(addr)		peek32(addr)
+#define	in16(addr)		peek16(addr)
+#define	in8(addr)		peek8(addr)
+
+#define	DISP_WIDTH	16
+#define	DISP_STEP	64
+#define	ADDR_RANGE	0x01000000
+
+/* ビットマスク（アドレス整列用） */
+static	uintptr_t	align_val(uintptr_t val, int bytes)
+{
+	switch (bytes) {
+	case	4:
+		val >>= 2; val <<= 2;
+		break;
+	case	2:
+		val >>= 1; val <<= 1;
+		break;
+	default:
+		/* do nothing */
+		break;
+	}
+
+	return val;
+}
+
+/* メモリ内容表示 */
+static	void	putxX_peekX(uintptr_t addr, int bytes)
+{
+	switch (bytes) {
+	case	4:
+		putx8(peek32(addr));
+		break;
+	case	2:
+		putx4(peek16(addr));
+		break;
+	case	1:
+		putx2(peek8(addr));
+		break;
+
+	case	-4:
+		putstr("    ");
+		/* fall-through */
+	case	-2:
+		putstr("  ");
+		/* fall-through */
+	case	-1:
+		putstr("  ");
+		break;
+	}
+
+	return;
+}
+
+/* メモリ書き込み */
+static	void	pokeX(uintptr_t addr, uint32_t val, int bytes)
+{
+	switch (bytes) {
+	case	4:
+		poke32(addr, val);
+		break;
+	case	2:
+		poke16(addr, val);
+		break;
+	case	1:
+		poke8(addr, val);
+		break;
+	}
+
+	return;
+}
+
+/* コマンド文字列：ビット幅の取得 */
+static	int	getbitwidth(char c)
+{
+	switch (c) {
+	case	'B':
+	case	'b':
+		return 1;
+	case	'H':
+	case	'h':
+		return 2;
+	case	'W':
+	case	'w':
+		return 4;
+	default:
+		return -1;
+	}
+}
+
+/* 16進数文字列→数値変換 */
+static	uint32_t	hextol(char *nptr, char **endptr)
+{
+	uint32_t	v = 0;
+	char	c;
+
+	while (1) {
+		c = *nptr;
+
+		if (c >= '0' && c <= '9') {
+			v = (v << 4) | (c - '0');
+		} else if (c >= 'A' && c <= 'F') {
+			v = (v << 4) | (c - 'A' + 10);
+		} else if (c >= 'a' && c <= 'f') {
+			v = (v << 4) | (c - 'a' + 10);
+		} else {
+			break;
+		}
+
+		nptr++;
+	}
+
+	*endptr = nptr;
+	return v;
+}
+
+/* 引数の取得 */
+static	int	getvalue(char *str, uint32_t *val, int maxval)
+{
+	int	n;
+	uint32_t	t;
+	char	*curr, *next;
+
+	n = 0;
+	curr = str;
+	while (1) {
+		t = hextol(curr, &next);
+		if (curr == next) {
+			/* 変換対象となる文字列が無い */
+			if (*curr == '\0') break;
+			else curr++;
+		} else {
+			/* 変換対象となる文字列がある */
+			val[n++] = t;
+			if (n >= maxval) break;
+			curr = next;
+		}
+	}
+
+	return n;
+}
+
+/* メモリダンプ */
+static	void	memory_dump(uintptr_t start_addr, intptr_t length, int bytes)
+{
+	intptr_t	remain;
+	int	i;
+	uint8_t	c;
+
+	/* 表示部分本体 */
+	while (1) {
+		remain = length;
+		remain = (remain < DISP_WIDTH) ? remain : DISP_WIDTH;
+		if (remain <= 0) break;
+
+		putxA(start_addr);
+		putstr(": ");
+
+		/* 16進数ダンプ */
+		for (i = 0; i < remain; i += bytes) {
+			putxX_peekX(start_addr + i, bytes);
+			putch(' ');
+		}
+		for (; i < DISP_WIDTH; i+= bytes) {
+			putxX_peekX(0, -bytes);
+			putch(' ');
+		}
+		putstr("  ");
+
+		/* ASCIIダンプ（表示可能な文字に限る） */
+		for (i = 0; i < remain; i++) {
+			c = peek8(start_addr + i);
+			putch((c >= ' ' && c <= '~') ? c : '.');
+		}
+		for (; i < DISP_WIDTH; i++) {
+			putch(' ');
+		}
+		putch('\n');
+
+		start_addr += remain;
+		length -= remain;
+	}
+
+	return;
+}
+
+/* メモリ内容表示 */
+static	int	command_dump(char *arg, uintptr_t *addr)
+{
+	int	err, bytes, n;
+	intptr_t	len;
+	uint32_t	val[2];
+	
+	err = bytes = getbitwidth(*arg++);
+	if (err < 0) goto fin0;
+
+	n = getvalue(arg, val, 2);
+	if (n) *addr = val[0];
+	*addr = align_val(*addr, bytes);
+
+	if (n >= 2) {
+		len = align_val(val[1] - val[0] + bytes, bytes);
+		if (len > ADDR_RANGE) {
+			err = -1;
+			goto fin0;
+		}
+	} else {
+		len = DISP_STEP;
+	}
+
+	memory_dump(*addr, len, bytes);
+	*addr += len;
+
+fin0:
+	return err;
+}
+
+/* メモリ書き換え（対話処理） */
+static	void	command_modify_interactive(uintptr_t addr, int bytes)
+{
+	char	buf[80];
+	uint32_t	val;
+
+	while (1) {
+		putxA(addr);
+		putstr(": ");
+
+		putxX_peekX(addr, bytes);
+		putstr(" -> ");
+
+		getstr(buf);
+
+		if (*buf == '.') break;
+		else if (getvalue(buf, &val, 1)) pokeX(addr, val, bytes);
+
+		addr += bytes;
+	}
+
+	return;
+}
+
+/* メモリ書き換え */
+static	int	command_modify(char *arg, uintptr_t *addr)
+{
+	int	err, bytes, n;
+	uint32_t	val[2];
+
+	err = bytes = getbitwidth(*arg++);
+	if (err < 0) goto fin0;
+
+	n = getvalue(arg, val, 2);
+	if (n) *addr = val[0];
+	*addr = align_val(*addr, bytes);
+
+	if (n >= 2) {
+		pokeX(*addr, val[1], bytes);
+	} else {
+		command_modify_interactive(*addr, bytes);
+	}
+
+fin0:
+	return err;
+}
+
+/* ポート入力 */
+static	int	command_inport(char *arg)
+{
+	int	err, bytes;
+	uintptr_t	addr;
+	uint32_t	val;
+
+	err = bytes = getbitwidth(*arg++);
+	if (err < 0) goto fin0;
+
+	if (getvalue(arg, &val, 1) != 1) {
+		err = -1;
+		goto fin0;
+	}
+
+	addr = align_val(val, bytes);
+	putstr("Port ");
+	putxA(addr);
+	putstr(" -> ");
+
+	switch (bytes) {
+	case	4:
+		putx8(in32(addr));
+		break;
+	case	2:
+		putx4(in16(addr));
+		break;
+	case	1:
+		putx2(in8(addr));
+		break;
+	}
+
+	putch('\n');
+
+fin0:
+	return err;
+}
+
+/* ポート出力 */
+static	int	command_outport(char *arg)
+{
+	int	err, bytes;
+	uintptr_t	addr;
+	uint32_t	val[2];
+
+	err = bytes = getbitwidth(*arg++);
+	if (err < 0) goto fin0;
+
+	if (getvalue(arg, val, 2) != 2) {
+		err = -1;
+		goto fin0;
+	}
+
+	addr = align_val(val[0], bytes);
+	putstr("Port ");
+	putxA(addr);
+	putstr(" <- ");
+
+	switch (bytes) {
+	case	4:
+		putx8(val[1]);	out32(addr, val[1]);
+		break;
+	case	2:
+		putx4(val[1]);	out16(addr, val[1]);
+		break;
+	case	1:
+		putx2(val[1]);	out8(addr, val[1]);
+		break;
+	}
+
+	putch('\n');
+
+fin0:
+	return err;
+}
+
+/* 実行 */
+static	int	command_go(char *arg)
+{
+	int	err, n;
+	uint32_t	val[2];
+	int	(*func)(int arg);
+
+	err = n = getvalue(arg, val, 2);
+	switch (n) {
+	case	0:
+		err = -1;
+		goto fin0;
+	case	1:
+		val[1] = 0;
+		break;
+	}
+
+	func = (void *)val[0];
+	(*func)(val[1]);
+
+fin0:
+	return err;
+}
+
+/* メイン */
+int	monitor_main(void)
+{
+	int	err;
+	uintptr_t	addr = 0;
+	char	buf[80];
+
+	while (1) {
+		putstr("monitor> ");
+
+		getstr(buf);
+
+		switch (*buf) {
+		case	'D':
+		case	'd':
+			err = command_dump(buf + 1, &addr);
+			break;
+		case	'M':
+		case	'm':
+			err = command_modify(buf + 1, &addr);
+			break;
+		case	'I':
+		case	'i':
+			err = command_inport(buf + 1);
+			break;
+		case	'O':
+		case	'o':
+			err = command_outport(buf + 1);
+			break;
+		case	'G':
+		case	'g':
+			err = command_go(buf + 1);
+			break;
+		case	'Q':
+		case	'q':
+			err = 0;
+			goto fin0;
+		default:
+			err = -1;
+			break;
+		}
+
+		if (err < 0) putstr("error.\n");
+	}
+
+fin0:
+	return err;
+}
diff -uNp bootload/monitor.h bootload.m/monitor.h
--- bootload/monitor.h	Thu Jan  1 09:00:00 1970
+++ bootload.m/monitor.h	Sat May  7 23:04:19 2011
@@ -0,0 +1,6 @@
+#ifndef	_MONITOR_H_INCLUDED_
+#define	_MONITOR_H_INCLUDED_
+
+int	monitor_main(void);
+
+#endif