Add support for command line editing

The current code for entering commands via the serial CLI is completely
refactored and moved out of rtlplayground.c into a separate file cmd_edit.c
putting code into BANK2.
The serial ring buffer sbuf[] is now exclusively used for receiving
keys, including escape sequences (DEL will generate a 4-byte escape
sequence). The command is now held in cmd_buffer. This reduces
XMEM use, because the serial buffer can be much smaller.

Supported is only editing the current command line via backspace, del,
cursor left and right.

Because the code cannot distinguish escape sequences which are not yet
complete (because the serial isr has not yet put all characters into
the serial buffer) from the dozens of unsupported ones (F-keys/home,
Page up/down, cursor up/down...) they are ignored and remain in the
serial buffer until the ring-pointer overwrites them. This is standard
behaviour for consoles, which will print out garbage for unsupported
characters. In this implementation, the command line buffer and the
visible command line in the terminal are always synced, so garbage
can be removed again by ediing the line.

The code makes several redundant checks in order to prevent race-conditions
between the serial ISR and the comand-editing code.

Makefile

@@ -27,7 +27,7 @@ all: create_build_dir $(VERSION_HEADER) $(SUBDIRS) $(BUILDDIR)rtlplayground.bin
 create_build_dir:
 	mkdir -p $(BUILDDIR)
 
-SRCS = rtlplayground.c rtl837x_flash.c rtl837x_leds.c rtl837x_phy.c rtl837x_port.c cmd_parser.c html_data.c rtl837x_igmp.c rtl837x_stp.c rtl837x_pins.c dhcp.c machine.c
+SRCS = rtlplayground.c rtl837x_flash.c rtl837x_leds.c rtl837x_phy.c rtl837x_port.c cmd_parser.c html_data.c rtl837x_igmp.c rtl837x_stp.c rtl837x_pins.c dhcp.c machine.c cmd_editor.c
 OBJS = ${SRCS:%.c=$(BUILDDIR)%.rel}
 OBJS += uip/$(BUILDDIR)/timer.rel uip/$(BUILDDIR)/uip-fw.rel uip/$(BUILDDIR)/uip-neighbor.rel uip/$(BUILDDIR)/uip-split.rel uip/$(BUILDDIR)/uip.rel uip/$(BUILDDIR)/uip_arp.rel uip/$(BUILDDIR)/uiplib.rel httpd/$(BUILDDIR)/httpd.rel httpd/$(BUILDDIR)/page_impl.rel
 

cmd_editor.c

@@ -0,0 +1,125 @@
+#include "cmd_parser.h"
+#include "machine.h"
+
+#pragma codeseg BANK2
+#pragma constseg BANK2
+
+// Position in the serial buffer
+__xdata uint8_t l;
+// Properties of currently edited command line in cmd_buffer[CMD_BUF_SIZE]
+__xdata uint8_t cursor;
+__xdata uint8_t cmd_line_len;
+
+
+void cmd_editor_init(void) __banked
+{
+	l = sbuf_ptr; // We have printed out entered characters until l
+	cursor = 0;
+	cmd_line_len = 0;
+	cmd_available = 0;
+}
+
+/*
+ * Allows editing the current command line held in cmd_buffer[CMD_BUF_SIZE] by
+ * identifying new characters typed or up to 4-byte escape sequences in the
+ * serial buffer ring sbuf[SBUF_SIZE].
+ * Upon detecting new characters or escape sequences, the cmd_buffer and the
+ * representation of the command line in the terminal are updated.
+ * To debug, the easist is to interpose a tty-interceptor between the physical
+ * serial device and a logical one created by interceptty:
+ * sudo interceptty -s 'ispeed 115200 ospeed 115200' /dev/ttyUSB0 /dev/tmpS
+ * picocom -b 115200 /dev/tmpS
+ */
+void cmd_edit(void) __banked
+{
+	while (l != sbuf_ptr) {
+		if (sbuf[l] >= ' ' && sbuf[l] < 127) { // A printable character, copy to command line
+			if (cmd_line_len >= CMD_BUF_SIZE)
+				continue;
+			write_char(sbuf[l]);
+			// Shift buffer to right
+			for (uint8_t i = cmd_line_len; i > cursor; i--)
+				cmd_buffer[i] = cmd_buffer[i-1];
+			// Insert char in comand buffer
+			cmd_buffer[cursor++] = sbuf[l];
+			cmd_line_len++;
+			// Print rest of line
+			for (uint8_t i = cursor; i < cmd_line_len; i++)
+				write_char(cmd_buffer[i]);
+			// Move backwards
+			for (uint8_t i = cursor; i < cmd_line_len; i++)
+				write_char('\010'); // BS works like cursor-left
+		} else if (sbuf[l] == '\033') { // ESC-Sequence
+			// Wait until we have at least 3 characters including the ESC character in the serial buffer
+			if (((sbuf_ptr + SBUF_SIZE - l) & SBUF_MASK) < 3)
+				continue;
+			if (((sbuf_ptr > l ? sbuf_ptr - l : SBUF_SIZE + sbuf_ptr - l) >= 4)
+				   && sbuf[l] == '\033' && sbuf[(l + 1) & SBUF_MASK] == '[' && sbuf[(l + 2) & SBUF_MASK] == '3' && sbuf[(l + 3) & SBUF_MASK] == '~') { // DEL
+				if (cursor < cmd_line_len) {
+					write_char('\033'); write_char('['); write_char('1'); write_char('P'); // Delete to end of line
+					cmd_line_len--;
+					for (uint8_t i = cursor; i < cmd_line_len; i++) {
+						cmd_buffer[i] = cmd_buffer[i+1];
+						write_char(cmd_buffer[i]);
+					}
+					for (uint8_t i = cursor; i < cmd_line_len; i++)
+						write_char('\010');
+				}
+				l += 4;
+				l &= SBUF_MASK;
+				continue;
+			} else if (sbuf[l] == '\033' && sbuf[(l + 1) & SBUF_MASK] == '[' && sbuf[(l + 2) & SBUF_MASK] == 'D') { // <CURSOR-LEFT>
+				if (cursor) {
+					write_char('\010'); // BS works like cursor-left
+					cursor--;
+				}
+				l += 3;
+				l &= SBUF_MASK;
+				continue;
+			} else if (sbuf[l] == '\033' && sbuf[(l + 1) & SBUF_MASK] == '[' && sbuf[(l + 2) & SBUF_MASK] == 'C') { // <CURSOR-RIGHT>
+				if (cursor < cmd_line_len) {
+					write_char('\033'); write_char('['); write_char('C');
+					cursor++;
+				}
+				l += 3;
+				l &= SBUF_MASK;
+				continue;
+			} else { // An unknown or not yet complete Escape sequence: wait
+				continue;
+			}
+		} else if (sbuf[l] == 127) {  // Backspace
+			if (cursor > 0) {
+				write_char('\010');
+				for (uint8_t i = cursor; i < cmd_line_len; i++)
+					write_char(cmd_buffer[i]);
+				write_char(' '); // Overwrite end of line
+				// Move backwards n steps:
+				for (uint8_t i = cursor; i <= cmd_line_len; i++)
+					write_char('\010');
+				cursor--;
+				for (uint8_t i = cursor; i <= cmd_line_len; i++)
+					cmd_buffer[i] = cmd_buffer[i+1];
+				cmd_line_len--;
+			}
+		}
+		// If the command buffer is currently in use, we cannot copy to it
+		if (cmd_available)
+			break;
+		// Check whether return was pressed:
+		if (sbuf[l] == '\n' || sbuf[l] == '\r') {
+			write_char('\n');
+			cmd_buffer[cmd_line_len] = '\0';
+			write_char('>'); print_string_x(cmd_buffer); write_char('<');
+			// If there is a command we print the prompt after execution
+			// otherwise immediately because there is nothing to execute
+			if (cmd_line_len)
+				cmd_available = 1;
+			else
+				print_string("\n> ");
+			cursor = 0;
+			cmd_line_len = 0;
+		}
+		l++;
+		l &= SBUF_MASK;
+	}
+}

cmd_editor.h

@@ -0,0 +1,9 @@
+#ifndef _CMD_EDITOR_H_
+#define _CMD_EDITOR_H_
+
+#include <stdint.h>
+
+void cmd_editor_init(void) __banked;
+void cmd_edit(void) __banked;
+
+#endif

cmd_parser.c

@@ -51,17 +51,16 @@ __xdata uint8_t hexvalue[4] = { 0 };
 
 
 // Buffer for writing to flash 0x1fd000, copy to 0x1fe000
-__xdata uint8_t cmd_buffer[SBUF_SIZE];
+__xdata uint8_t cmd_buffer[CMD_BUF_SIZE];
 __xdata uint8_t cmd_available;
 
-__xdata	uint8_t l;
 __xdata uint8_t line_ptr;
 __xdata	char is_white;
 __xdata	char save_cmd;
 
 __xdata uint8_t ip[4];
 
-#define N_WORDS SBUF_SIZE
+#define N_WORDS CMD_BUF_SIZE
 __xdata signed char cmd_words_b[N_WORDS];
 
 __xdata uint8_t cmd_history[CMD_HISTORY_SIZE];
@@ -93,7 +92,7 @@ uint8_t cmd_compare(uint8_t start, uint8_t * __code cmd)
 	signed char j = 0;
 
 	for (i = cmd_words_b[start]; i != cmd_words_b[start + 1] && cmd_buffer[i] != ' '; i++) {
-		i &= SBUF_SIZE - 1;
+		i &= CMD_BUF_SIZE - 1;
 //		print_byte(i); write_char(':'); print_byte(j); write_char('#'); print_string("\n");
 //		write_char('>'); write_char(cmd[j]); write_char('-'); write_char(cmd_buffer[i]); print_string("\n");
 		if (!cmd[j] && !isletter(cmd_buffer[i]))
@@ -710,7 +709,7 @@ uint8_t cmd_tokenize(void) __banked
 	is_white = 1;
 	uint8_t word = 0;
 	cmd_words_b[0] = -1;
-	while (cmd_buffer[line_ptr] && line_ptr < SBUF_SIZE - 1) {
+	while (cmd_buffer[line_ptr] && line_ptr < CMD_BUF_SIZE - 1) {
 		if (is_white && cmd_buffer[line_ptr] != ' ') {
 			is_white = 0;
 			cmd_words_b[word++] = line_ptr;
@@ -723,7 +722,7 @@ uint8_t cmd_tokenize(void) __banked
 			return 1;
 		}
 	}
-	if (line_ptr == SBUF_SIZE - 1)
+	if (line_ptr == CMD_BUF_SIZE - 1)
 		return 1;
 	cmd_words_b[word++] = line_ptr;
 	cmd_words_b[word++] = -1;
@@ -1001,6 +1000,16 @@ void cmd_parser(void) __banked
 	}
 }
 
+
+void clear_command_history(void) __banked
+{
+	for (cmd_history_ptr = 0; cmd_history_ptr < CMD_HISTORY_SIZE; cmd_history_ptr++)
+		cmd_history[cmd_history_ptr] = 0;
+	cmd_history_ptr = 0;
+	return;
+}
+
+
 #define FLASH_READ_BURST_SIZE 0x100
 #define PASSWORD "1234"
 void execute_config(void) __banked
@@ -1020,7 +1029,7 @@ void execute_config(void) __banked
 		__xdata uint8_t cfg_idx = 0;
 		uint8_t c = 0;
 		do {
-			for (uint8_t cmd_idx = 0; cmd_idx < (SBUF_SIZE - 1); cmd_idx++) {
+			for (uint8_t cmd_idx = 0; cmd_idx < (CMD_BUF_SIZE - 1); cmd_idx++) {
 				c = flash_buf[cfg_idx++];
 				if (c == 0 || c == '\n') {
 					cmd_buffer[cmd_idx] = '\0';
@@ -1041,13 +1050,6 @@ void execute_config(void) __banked
 
 config_done:
 	// Start saving commands to cmd_history
+	clear_command_history();
 	save_cmd = 1;
 }
-
-void clear_command_history(void) __banked
-{
-	for (cmd_history_ptr = 0; cmd_history_ptr < CMD_HISTORY_SIZE; cmd_history_ptr++)
-		cmd_history[cmd_history_ptr] = 0;
-	cmd_history_ptr = 0;
-	return;
-}

cmd_parser.h

@@ -5,7 +5,7 @@
 
 #include "rtl837x_common.h"
 
-extern __xdata uint8_t cmd_buffer[SBUF_SIZE];
+extern __xdata uint8_t cmd_buffer[CMD_BUF_SIZE];
 extern __xdata uint8_t cmd_available;
 
 uint8_t cmd_tokenize(void) __banked;

machine.c

@@ -75,7 +75,7 @@ void machine_custom_init(void) { }
 
 #elif defined MACHINE_KP_9000_9XH_X_EU
 __code const struct machine machine = {
-	.machine_name = "keepLink KP-9000-6XH-X-EU",
+	.machine_name = "keepLink KP-9000-9XH-X-EU",
 	.isRTL8373 = 1,
 	.min_port = 0,
 	.max_port = 8,

rtl837x_common.h

@@ -19,9 +19,19 @@
 #define LOOKUP_MISS_DROP_9  0x00015555
 #define LOOKUP_MISS_FLOOD   0x00000000
 
-// The serial buffer. Defines the command line size
-// Must be 2^x and <= 128
-#define SBUF_SIZE 128
+/* Buffer for serial input, SBUF_SIZE must be power of 2 < 256
+ * Writing to this buffer is under the sole control of the serial ISR
+ * Note that key-presses such as <cursor-left> can create multiple
+ * keys (3 to 4) being sent via the serial line, so this must be
+ * sufficiently large */
+#define SBUF_SIZE 16
+#define SBUF_MASK (SBUF_SIZE - 1)
+
+extern __xdata volatile uint8_t sbuf_ptr;
+extern __xdata uint8_t sbuf[SBUF_SIZE];
+
+// Define the command buffer size, Must be 2^x and <= 128
+#define CMD_BUF_SIZE 128
 
 // Size of the TCP Output buffer
 #define TCP_OUTBUF_SIZE 2500
@@ -90,6 +100,7 @@ extern __xdata struct uip_eth_addr uip_ethaddr;
 
 // Headers for calls in the common code area (HOME/BANK0)
 void print_string(__code char *p);
+void print_string_x(__xdata char *p);
 void print_long(__xdata uint32_t a);
 void print_short(uint16_t a);
 void print_byte(uint8_t a);
@@ -121,7 +132,6 @@ uint16_t strlen(register __code const char *s);
 uint16_t strlen_x(register __xdata const char *s);
 uint16_t strtox(register __xdata uint8_t *dst, register __code const char *s);
 void tcpip_output(void);
-void print_string_x(__xdata char *p);
 uint8_t read_flash(uint8_t bank, __code uint8_t *addr);
 void get_random_32(void);
 void read_reg_timer(uint32_t * tmr);

rtlplayground.c

@@ -16,6 +16,7 @@
 #include "rtl837x_leds.h"
 #include "dhcp.h"
 #include "cmd_parser.h"
+#include "cmd_editor.h"
 #include "uip/uipopt.h"
 #include "uip/uip.h"
 #include "uip/uip_arp.h"
@@ -86,10 +87,13 @@ extern __xdata struct dhcp_state dhcp_state;
 
 #define STP_TICK_DIVIDER 3
 
-
-// Buffer for serial input, SBUF_SIZE must be power of 2 < 256
+/* Buffer for serial input, SBUF_SIZE must be power of 2 < 256
+ * Writing to this buffer is under the sole control of the serial ISR
+ * Note that key-presses such as <cursor-left> can create multiple
+ * keys being sent via the serial line */
 __xdata volatile uint8_t sbuf_ptr;
 __xdata uint8_t sbuf[SBUF_SIZE];
+
 __xdata uint8_t sfr_data[4];
 
 extern __xdata uint8_t gpio_last_value[8];
@@ -2102,39 +2106,9 @@ void bootloader(void)
 
 	set_sys_led_state(SYS_LED_ON);
 
-	// Wait for commands on serial connection
-	// sbuf_ptr is moved forward by serial interrupt, l is the position until we have already
-	// printed out the entered characters
-	__xdata uint8_t l = sbuf_ptr; // We have printed out entered characters until l
-	__xdata uint8_t line_start = sbuf_ptr; // This is where the current line starts
-	cmd_available = 0;
+	cmd_editor_init();
 	while (1) {
-		while (l != sbuf_ptr) {
-			// If the command buffer is currently in use, we cannot copy to it
-			if (cmd_available)
-				break;
-			write_char(sbuf[l]);
-			// Check whether there is a full line:
-			if (sbuf[l] == '\n' || sbuf[l] == '\r') {
-				write_char('\n');
-				register uint8_t i = 0;
-				while (line_start != l) {
-					cmd_buffer[i++] = sbuf[line_start++];
-					line_start &= (SBUF_SIZE - 1);
-				}
-				line_start++;
-				line_start &= (SBUF_SIZE - 1);
-				cmd_buffer[i] = '\0';
-				// If there is a command we print the prompt after execution
-				// otherwise immediately because there is nothing to execute
-				if (i)
-					cmd_available = 1;
-				else
-					print_string("\n> ");
-			}
-			l++;
-			l &= (SBUF_SIZE - 1);
-		}
+		cmd_edit();
 		idle(); // Enter Idle mode until interrupt occurs
 	}
 }