Add memory commands (cmp, cp, md, mm, mw, nm)

Add kind of scheduler for background tasks

1 files changed, 878 insertions, 0 deletions

diff --git a/avr/cmd_mem.c b/avr/cmd_mem.c
new file mode 100644
index 0000000..df30196
--- /dev/null
+++ b/avr/cmd_mem.c
@@ -0,0 +1,878 @@
+/*
+ * (C) Copyright 2000
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/*
+ * Memory Functions
+ *
+ * Copied from FADS ROM, Dan Malek (dmalek@jlc.net)
+ */
+
+#include "common.h"
+#include <stdlib.h>
+#include <ctype.h>
+
+#include "config.h"
+#include "debug.h"
+#include "command.h"
+#include "cli_readline.h"
+#include "con-utils.h"
+#include "z80-if.h"
+
+/* 
+ * TODO: printf() --> printf_P() 
+ */
+
+#ifndef CONFIG_SYS_MEMTEST_SCRATCH
+#define CONFIG_SYS_MEMTEST_SCRATCH 0
+#endif
+
+static int mod_mem(cmd_tbl_t *, int, int, int, char * const []);
+
+/* Display values from last command.
+ * Memory modify remembered values are different from display memory.
+ */
+static uint32_t	dp_last_addr;
+static uint32_t	dp_last_length = 0x100;
+static uint32_t	mm_last_addr;
+
+static	uint32_t	base_address = 0;
+
+/*--------------------------------------------------------------------------*/
+
+static void print_blanks(uint_fast8_t count)
+{
+	while(count--)
+		putchar(' ');
+}
+
+int z180_dump_mem(uint32_t startaddr, uint32_t len, const char *title)
+{
+	uint8_t buf[16];
+	uint8_t llen = 16;
+	uint8_t pre = startaddr % 16;
+	uint32_t addr = startaddr & ~0x0f;
+	len += pre;
+	uint8_t i;
+	
+	if (title && *title)
+		printf_P(PSTR("%s\n"),title);
+		
+	while (len) {
+		if (len < 16)
+			llen = len;
+
+		z80_request_bus();
+		for (i = pre; i < llen; i++)
+			buf[i] = z80_read(addr + i);
+		z80_release_bus();
+
+		printf_P(PSTR("%.5lx:"), addr);
+#if 0
+		print_blanks(3 * pre);
+
+		/* Print hex values */
+		for (i = pre; i < llen; i++)
+			printf_P(PSTR(" %.2x"), buf[i]);
+#else
+		for (i = 0; i < llen; i++) {
+			if ((i % 8) == 0)
+				putchar(' ');
+			if (i < pre)
+				printf_P(PSTR(".. "));
+			else
+				printf_P(PSTR("%.2x "), buf[i]);
+		}
+#endif
+		/* fill line with whitespace for nice ASCII print */
+#if 1
+		print_blanks(3 * (16u - i) + (16u-i)/8 + 1 + pre);
+#else
+
+#endif
+		/* Print data in ASCII characters */
+		for (i = pre; i < llen; i++)
+			printf_P(PSTR("%c"), isprint(buf[i]) ? buf[i] : '.');
+		putchar('\n');
+
+		pre = 0;
+		addr += 16;
+		len -= llen;
+
+		if (ctrlc())
+			return -1;
+	}
+	return 0;
+}
+
+
+/*--------------------------------------------------------------------------*/
+
+/* Memory Display
+ *
+ * Syntax:
+ *	md {addr} {len}
+ */
+int do_mem_md(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	uint32_t addr, length;
+	
+	(void) cmdtp;
+
+#if 0	
+	printf_P(PSTR("flag: %d, argc: %d"), flag, argc);
+	for (int i = 0; i < argc; i++) {
+		printf_P(PSTR(", argv[%d]: %s"), i, argv[i] ? argv[i] : "<NULL>");
+	}
+	putchar('\n');
+#endif
+
+	/* We use the last specified parameters, unless new ones are
+	 * entered.
+	 */
+	addr = dp_last_addr;
+	length = dp_last_length;
+
+	if (argc < 2)
+		return CMD_RET_USAGE;
+
+	if ((flag & CMD_FLAG_REPEAT) == 0) {
+		/* Address is specified since argc > 1 */
+		addr = strtoul(argv[1], NULL, 16);
+		addr += base_address;
+
+		/* If another parameter, it is the length to display. */
+		if (argc > 2)
+			length = strtoul(argv[2], NULL, 16);
+	}
+
+	/* Print the lines. */
+	z180_dump_mem(addr, length, NULL);
+
+	dp_last_addr = addr + length;
+	dp_last_length = length;
+	return 0;
+}
+
+int do_mem_mm(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	return mod_mem (cmdtp, 1, flag, argc, argv);
+}
+int do_mem_nm(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	return mod_mem (cmdtp, 0, flag, argc, argv);
+}
+
+int do_mem_mw(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	uint8_t writeval;
+	uint32_t addr, count;
+
+	(void) cmdtp;
+	(void) flag;
+
+	if ((argc < 3) || (argc > 4))
+		return CMD_RET_USAGE;
+
+	/* Address is specified since argc > 1
+	*/
+	addr = strtoul(argv[1], NULL, 16);
+	addr += base_address;
+
+	/* Get the value to write.
+	*/
+	writeval = (uint8_t) strtoul(argv[2], NULL, 16);
+
+	/* Count ? */
+	if (argc == 4) {
+		count = strtoul(argv[3], NULL, 16);
+	} else {
+		count = 1;
+	}
+
+	z80_request_bus();
+	while (count-- > 0) {
+		z80_write(addr, writeval);
+		++addr; 
+	}
+	z80_release_bus();
+
+	return 0;
+}
+
+#ifdef CONFIG_MX_CYCLIC
+int do_mem_mdc ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	int i;
+	uint32_t count;
+
+	if (argc < 4)
+		return CMD_RET_USAGE;
+
+	count = strtoul(argv[3], NULL, 10);
+
+	for (;;) {
+		do_mem_md (NULL, 0, 3, argv);
+
+		/* delay for <count> ms... */
+/* TODO: use timer */
+		for (i=0; i<count; i++)
+			udelay (1000);
+
+		/* check for ctrl-c to abort... */
+		if (ctrlc()) {
+			my_puts("Abort\n");
+			return 0;
+		}
+	}
+
+	return 0;
+}
+
+int do_mem_mwc ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	int i;
+	uint32_t count;
+
+	if (argc < 4)
+		return CMD_RET_USAGE;
+
+	count = strtoul(argv[3], NULL, 10);
+
+	for (;;) {
+		do_mem_mw (NULL, 0, 3, argv);
+
+		/* delay for <count> ms... */
+/* TODO: use timer */
+		for (i=0; i<count; i++)
+			udelay (1000);
+
+		/* check for ctrl-c to abort... */
+		if (ctrlc()) {
+			my_puts("Abort\n");
+			return 0;
+		}
+	}
+
+	return 0;
+}
+#endif /* CONFIG_MX_CYCLIC */
+
+int do_mem_cmp(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	uint32_t addr1, addr2, count, ngood;
+	int rcode = 0;
+	uint8_t byte1, byte2;
+
+	(void) cmdtp;
+	(void) flag;
+
+	if (argc != 4)
+		return CMD_RET_USAGE;
+
+
+	addr1 = strtoul(argv[1], NULL, 16);
+	addr1 += base_address;
+	addr2 = strtoul(argv[2], NULL, 16);
+	addr2 += base_address;
+	count = strtoul(argv[3], NULL, 16);
+
+	for (ngood = 0; ngood < count; ++ngood) {
+		z80_request_bus();
+		byte1 = z80_read(addr1);
+		byte2 = z80_read(addr2);
+		z80_release_bus();
+		if (byte1 != byte2) {
+			printf(	"byte at 0x%05lx (%#02x) != "
+				"byte at 0x%05lx (%#02x)\n",
+				addr1, byte1, addr2, byte2);
+			rcode = 1;
+			break;
+		}
+		addr1++;
+		addr2++;
+
+		/* check for ctrl-c to abort... */
+		if (ctrlc()) {
+			my_puts("Abort\n");
+			return 0;
+		}
+	}
+
+	printf("Total of %ld byte(s) (0x%lx) were the same\n", ngood, ngood);
+	return rcode;
+}
+
+int do_mem_cp(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	uint32_t src, dest, count;
+	int_fast8_t step;
+
+	(void) cmdtp;
+	(void) flag;
+
+	if (argc != 4)
+		return CMD_RET_USAGE;
+
+	src = strtoul(argv[1], NULL, 16);
+	src += base_address;
+	dest = strtoul(argv[2], NULL, 16);
+	dest += base_address;
+	count = strtoul(argv[3], NULL, 16);
+
+	if (count == 0) {
+		my_puts ("Zero length ???\n");
+		return 1;
+	}
+	
+	if (dest > src) {
+		src += count - 1;
+		dest += count - 1;
+		step = -1;
+	} else
+		step = 1;
+
+	while (count-- > 0) {
+		uint8_t data;
+		z80_request_bus();
+		data = z80_read(src);
+		z80_write(dest, data);
+		z80_release_bus();
+		src += step;
+		dest += step;
+
+		/* check for ctrl-c to abort... */
+		if (ctrlc()) {
+			my_puts("Abort\n");
+			return 0;
+		}
+	}
+	return 0;
+}
+
+int do_mem_base(cmd_tbl_t *cmdtp, int flag, int argc,
+		       char * const argv[])
+{
+	(void) cmdtp;
+	(void) flag;
+
+	if (argc > 1) {
+		/* Set new base address. */
+		base_address = strtoul(argv[1], NULL, 16);
+	}
+	/* Print the current base address. */
+	printf("Base Address: 0x%05lx\n", base_address);
+	return 0;
+}
+
+int do_mem_loop(cmd_tbl_t *cmdtp, int flag, int argc,
+		       char * const argv[])
+{
+	uint32_t addr, length;
+
+	(void) cmdtp;
+	(void) flag;
+
+	if (argc < 3)
+		return CMD_RET_USAGE;
+
+	/* Address is always specified. */
+	addr = strtoul(argv[1], NULL, 16);
+
+	/* Length is the number of bytes. */
+	length = strtoul(argv[2], NULL, 16);
+
+
+	/* We want to optimize the loops to run as fast as possible.
+	 * If we have only one object, just run infinite loops.
+	 */
+	if (length == 1) {
+		z80_request_bus();
+		for (;;)
+			z80_read(addr);
+		z80_release_bus();
+	}
+
+	z80_request_bus();
+	for (;;) {
+		uint32_t i = length;
+		uint32_t p = addr;
+		while (i-- > 0)
+			z80_read(p++);
+	}
+	z80_release_bus();
+
+	return 0;
+}
+
+#ifdef CONFIG_LOOPW
+int do_mem_loopw (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	uint32_t addr, length;
+	uint8_t	data;
+
+	(void) cmdtp;
+	(void) flag;
+
+	if (argc < 4)
+		return CMD_RET_USAGE;
+
+	/* Address is always specified. */
+	addr = strtoul(argv[1], NULL, 16);
+
+	/* Length is the number of bytes. */
+	length = strtoul(argv[2], NULL, 16);
+
+	data = strtoul(argv[3], NULL, 16);
+
+	/* We want to optimize the loops to run as fast as possible.
+	 * If we have only one object, just run infinite loops.
+	 */
+	if (length == 1) {
+		z80_request_bus();
+		for (;;)
+			z80_write(addr, data);
+	}
+
+	for (;;) {
+		uint32_t i = length;
+		uint32_t p = addr;
+		while (i-- > 0)
+			z80_write(p++, data);
+	}
+}
+#endif /* CONFIG_LOOPW */
+
+#ifdef CONFIG_CMD_MEMTEST
+static uint32_t mem_test_alt(vu_long *buf, uint32_t start_addr, uint32_t end_addr,
+			  vu_long *dummy)
+{
+	vu_long *addr;
+	uint32_t errs = 0;
+	uint32_t val, readback;
+	int j;
+	vu_long offset;
+	vu_long test_offset;
+	vu_long pattern;
+	vu_long temp;
+	vu_long anti_pattern;
+	vu_long num_words;
+	static const FLASH uint32_t bitpattern[] = {
+		0x00000001,	/* single bit */
+		0x00000003,	/* two adjacent bits */
+		0x00000007,	/* three adjacent bits */
+		0x0000000F,	/* four adjacent bits */
+		0x00000005,	/* two non-adjacent bits */
+		0x00000015,	/* three non-adjacent bits */
+		0x00000055,	/* four non-adjacent bits */
+		0xaaaaaaaa,	/* alternating 1/0 */
+	};
+
+	num_words = (end_addr - start_addr) / sizeof(vu_long);
+
+	/*
+	 * Data line test: write a pattern to the first
+	 * location, write the 1's complement to a 'parking'
+	 * address (changes the state of the data bus so a
+	 * floating bus doesn't give a false OK), and then
+	 * read the value back. Note that we read it back
+	 * into a variable because the next time we read it,
+	 * it might be right (been there, tough to explain to
+	 * the quality guys why it prints a failure when the
+	 * "is" and "should be" are obviously the same in the
+	 * error message).
+	 *
+	 * Rather than exhaustively testing, we test some
+	 * patterns by shifting '1' bits through a field of
+	 * '0's and '0' bits through a field of '1's (i.e.
+	 * pattern and ~pattern).
+	 */
+	addr = buf;
+	for (j = 0; j < sizeof(bitpattern) / sizeof(bitpattern[0]); j++) {
+		val = bitpattern[j];
+		for (; val != 0; val <<= 1) {
+			*addr = val;
+			*dummy  = ~val; /* clear the test data off the bus */
+			readback = *addr;
+			if (readback != val) {
+				printf("FAILURE (data line): "
+					"expected %05lx, actual %05lx\n",
+						val, readback);
+				errs++;
+				if (ctrlc())
+					return -1;
+			}
+			*addr  = ~val;
+			*dummy  = val;
+			readback = *addr;
+			if (readback != ~val) {
+				printf("FAILURE (data line): "
+					"Is %05lx, should be %05lx\n",
+						readback, ~val);
+				errs++;
+				if (ctrlc())
+					return -1;
+			}
+		}
+	}
+
+	/*
+	 * Based on code whose Original Author and Copyright
+	 * information follows: Copyright (c) 1998 by Michael
+	 * Barr. This software is placed into the public
+	 * domain and may be used for any purpose. However,
+	 * this notice must not be changed or removed and no
+	 * warranty is either expressed or implied by its
+	 * publication or distribution.
+	 */
+
+	/*
+	* Address line test
+
+	 * Description: Test the address bus wiring in a
+	 *              memory region by performing a walking
+	 *              1's test on the relevant bits of the
+	 *              address and checking for aliasing.
+	 *              This test will find single-bit
+	 *              address failures such as stuck-high,
+	 *              stuck-low, and shorted pins. The base
+	 *              address and size of the region are
+	 *              selected by the caller.
+
+	 * Notes:	For best results, the selected base
+	 *              address should have enough LSB 0's to
+	 *              guarantee single address bit changes.
+	 *              For example, to test a 64-Kbyte
+	 *              region, select a base address on a
+	 *              64-Kbyte boundary. Also, select the
+	 *              region size as a power-of-two if at
+	 *              all possible.
+	 *
+	 * Returns:     0 if the test succeeds, 1 if the test fails.
+	 */
+	pattern = (vu_long) 0xaaaaaaaa;
+	anti_pattern = (vu_long) 0x55555555;
+
+	debug("%s:%d: length = 0x%.5lx\n", __func__, __LINE__, num_words);
+	/*
+	 * Write the default pattern at each of the
+	 * power-of-two offsets.
+	 */
+	for (offset = 1; offset < num_words; offset <<= 1)
+		addr[offset] = pattern;
+
+	/*
+	 * Check for address bits stuck high.
+	 */
+	test_offset = 0;
+	addr[test_offset] = anti_pattern;
+
+	for (offset = 1; offset < num_words; offset <<= 1) {
+		temp = addr[offset];
+		if (temp != pattern) {
+			printf("\nFAILURE: Address bit stuck high @ 0x%.5lx:"
+				" expected 0x%.5lx, actual 0x%.5lx\n",
+				start_addr + offset*sizeof(vu_long),
+				pattern, temp);
+			errs++;
+			if (ctrlc())
+				return -1;
+		}
+	}
+	addr[test_offset] = pattern;
+
+	/*
+	 * Check for addr bits stuck low or shorted.
+	 */
+	for (test_offset = 1; test_offset < num_words; test_offset <<= 1) {
+		addr[test_offset] = anti_pattern;
+
+		for (offset = 1; offset < num_words; offset <<= 1) {
+			temp = addr[offset];
+			if ((temp != pattern) && (offset != test_offset)) {
+				printf("\nFAILURE: Address bit stuck low or"
+					" shorted @ 0x%.5lx: expected 0x%.5lx,"
+					" actual 0x%.5lx\n",
+					start_addr + offset*sizeof(vu_long),
+					pattern, temp);
+				errs++;
+				if (ctrlc())
+					return -1;
+			}
+		}
+		addr[test_offset] = pattern;
+	}
+
+	/*
+	 * Description: Test the integrity of a physical
+	 *		memory device by performing an
+	 *		increment/decrement test over the
+	 *		entire region. In the process every
+	 *		storage bit in the device is tested
+	 *		as a zero and a one. The base address
+	 *		and the size of the region are
+	 *		selected by the caller.
+	 *
+	 * Returns:     0 if the test succeeds, 1 if the test fails.
+	 */
+	num_words++;
+
+	/*
+	 * Fill memory with a known pattern.
+	 */
+	for (pattern = 1, offset = 0; offset < num_words; pattern++, offset++) {
+		addr[offset] = pattern;
+	}
+
+	/*
+	 * Check each location and invert it for the second pass.
+	 */
+	for (pattern = 1, offset = 0; offset < num_words; pattern++, offset++) {
+		temp = addr[offset];
+		if (temp != pattern) {
+			printf("\nFAILURE (read/write) @ 0x%.5lx:"
+				" expected 0x%.5lx, actual 0x%.5lx)\n",
+				start_addr + offset*sizeof(vu_long),
+				pattern, temp);
+			errs++;
+			if (ctrlc())
+				return -1;
+		}
+
+		anti_pattern = ~pattern;
+		addr[offset] = anti_pattern;
+	}
+
+	/*
+	 * Check each location for the inverted pattern and zero it.
+	 */
+	for (pattern = 1, offset = 0; offset < num_words; pattern++, offset++) {
+		WATCHDOG_RESET();
+		anti_pattern = ~pattern;
+		temp = addr[offset];
+		if (temp != anti_pattern) {
+			printf("\nFAILURE (read/write): @ 0x%.5lx:"
+				" expected 0x%.5lx, actual 0x%.5lx)\n",
+				start_addr + offset*sizeof(vu_long),
+				anti_pattern, temp);
+			errs++;
+			if (ctrlc())
+				return -1;
+		}
+		addr[offset] = 0;
+	}
+
+	return 0;
+}
+
+static uint32_t mem_test_quick(vu_long *buf, uint32_t start_addr, uint32_t end_addr,
+			    vu_long pattern, int iteration)
+{
+	vu_long *end;
+	vu_long *addr;
+	uint32_t errs = 0;
+	uint32_t incr, length;
+	uint32_t val, readback;
+
+	/* Alternate the pattern */
+	incr = 1;
+	if (iteration & 1) {
+		incr = -incr;
+		/*
+		 * Flip the pattern each time to make lots of zeros and
+		 * then, the next time, lots of ones.  We decrement
+		 * the "negative" patterns and increment the "positive"
+		 * patterns to preserve this feature.
+		 */
+		if (pattern & 0x80000000)
+			pattern = -pattern;	/* complement & increment */
+		else
+			pattern = ~pattern;
+	}
+	length = (end_addr - start_addr) / sizeof(uint32_t);
+	end = buf + length;
+	printf("\rPattern %08lX  Writing..."
+		"%12s"
+		"\b\b\b\b\b\b\b\b\b\b",
+		pattern, "");
+
+	for (addr = buf, val = pattern; addr < end; addr++) {
+		*addr = val;
+		val += incr;
+	}
+
+	my_puts("Reading...");
+
+	for (addr = buf, val = pattern; addr < end; addr++) {
+		readback = *addr;
+		if (readback != val) {
+			uint32_t offset = addr - buf;
+
+			printf("\nMem error @ 0x%08X: "
+				"found %08lX, expected %08lX\n",
+				(unsigned int)(uintptr_t)(start_addr + offset*sizeof(vu_long)),
+				readback, val);
+			errs++;
+			if (ctrlc())
+				return -1;
+		}
+		val += incr;
+	}
+
+	return 0;
+}
+
+/*
+ * Perform a memory test. A more complete alternative test can be
+ * configured using CONFIG_SYS_ALT_MEMTEST. The complete test loops until
+ * interrupted by ctrl-c or by a failure of one of the sub-tests.
+ */
+int do_mem_mtest(cmd_tbl_t *cmdtp, int flag, int argc,
+			char * const argv[])
+{
+	uint32_t start, end;
+	vu_long *buf, *dummy;
+	int iteration_limit;
+	int ret;
+	uint32_t errs = 0;	/* number of errors, or -1 if interrupted */
+	uint32_t pattern;
+	int iteration;
+#if defined(CONFIG_SYS_ALT_MEMTEST)
+	const int alt_test = 1;
+#else
+	const int alt_test = 0;
+#endif
+
+	if (argc > 1)
+		start = strtoul(argv[1], NULL, 16);
+	else
+		start = CONFIG_SYS_MEMTEST_START;
+
+	if (argc > 2)
+		end = strtoul(argv[2], NULL, 16);
+	else
+		end = CONFIG_SYS_MEMTEST_END;
+
+	if (argc > 3)
+		pattern = (uint32_t)strtoul(argv[3], NULL, 16);
+	else
+		pattern = 0;
+
+	if (argc > 4)
+		iteration_limit = (uint32_t)strtoul(argv[4], NULL, 16);
+	else
+		iteration_limit = 0;
+
+	printf("Testing %08x ... %08x:\n", (unsigned int)start, (unsigned int)end);
+	debug("%s:%d: start %#05lx end %#05lx\n", __func__, __LINE__,
+	      start, end);
+
+/* TODO: */
+//	buf = map_sysmem(start, end - start);
+//	dummy = map_sysmem(CONFIG_SYS_MEMTEST_SCRATCH, sizeof(vu_long));
+	for (iteration = 0;
+			!iteration_limit || iteration < iteration_limit;
+			iteration++) {
+		if (ctrlc()) {
+			errs = -1UL;
+			break;
+		}
+
+		printf("Iteration: %6d\r", iteration + 1);
+		debug("\n");
+		if (alt_test) {
+			errs = mem_test_alt(buf, start, end, dummy);
+		} else {
+			errs = mem_test_quick(buf, start, end, pattern,
+					      iteration);
+		}
+		if (errs == -1UL)
+			break;
+	}
+
+	if (errs == -1UL) {
+		/* Memory test was aborted - write a newline to finish off */
+		putc('\n');
+		ret = 1;
+	} else {
+		printf("Tested %d iteration(s) with %lu errors.\n",
+			iteration, errs);
+		ret = errs != 0;
+	}
+
+	return ret;	/* not reached */
+}
+#endif	/* CONFIG_CMD_MEMTEST */
+
+/* Modify memory.
+ *
+ * Syntax:
+ *	mm {addr}
+ *	nm {addr}
+ */
+static int
+mod_mem(cmd_tbl_t *cmdtp, int incrflag, int flag, int argc, char * const argv[])
+{
+	uint32_t addr;
+	uint8_t data;
+	int nbytes;
+
+	(void) cmdtp;
+
+	if (argc != 2)
+		return CMD_RET_USAGE;
+
+	/* We use the last specified parameters, unless new ones are
+	 * entered.
+	 */
+	addr = mm_last_addr;
+
+	if ((flag & CMD_FLAG_REPEAT) == 0) {
+		/* New command specified.  
+		 */
+
+		/* Address is specified since argc > 1
+		*/
+		addr = strtoul(argv[1], NULL, 16);
+		addr += base_address;
+	}
+
+	/* Print the address, followed by value.  Then accept input for
+	 * the next value.  A non-converted value exits.
+	 */
+	do {
+		z80_request_bus();
+		data = z80_read(addr);
+		printf("%05lx: %02x", addr, data);
+		z80_release_bus();
+
+		nbytes = cli_readline(PSTR(" ? "));
+		if (nbytes == 0 || (nbytes == 1 && console_buffer[0] == '-')) {
+			/* <CR> pressed as only input, don't modify current
+			 * location and move to next. "-" pressed will go back.
+			 */
+			if (incrflag)
+				addr += nbytes ? -1 : 1;
+			nbytes = 1;
+		}
+		else {
+			char *endp;
+			data = strtoul(console_buffer, &endp, 16);
+			nbytes = endp - console_buffer;
+			if (nbytes) {
+				z80_request_bus();
+				z80_write(addr, data);
+				z80_release_bus();
+				if (incrflag)
+					addr++;
+			}
+		}
+	} while (nbytes);
+
+	mm_last_addr = addr;
+	return 0;
+}
+