From 8468f22e581a29baac58bd2ef3257b0d048b146a Mon Sep 17 00:00:00 2001
From: Markus Hitter <mah@jump-ing.de>
Date: Sun, 4 Jul 2010 18:34:24 +0200
Subject: [PATCH] Eliminate serial_writechar_P(). serial_writechar() perfoms
 better and uses less memory. Also, reviewed all code for usage of
 single-character strings.

---
 mendel/gcode.c  |  6 +++---
 mendel/serial.c | 14 ++++++++------
 mendel/serial.h |  1 -
 3 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/mendel/gcode.c b/mendel/gcode.c
index d8bceba..01e0a58 100644
--- a/mendel/gcode.c
+++ b/mendel/gcode.c
@@ -332,14 +332,14 @@ void scan_char(uint8_t c) {
 			else {
 				serial_writestr_P(PSTR("Expected checksum "));
 				serwrite_uint8(next_target.checksum_calculated);
-				serial_writestr_P(PSTR("\n"));
+				serial_writechar('\n');
 				request_resend();
 			}
 		}
 		else {
 			serial_writestr_P(PSTR("Expected line number "));
 			serwrite_uint32(next_target.N_expected);
-			serial_writestr_P(PSTR("\n"));
+			serial_writechar('\n');
 			request_resend();
 		}
 
@@ -735,6 +735,6 @@ void process_gcode_command(GCODE_COMMAND *gcmd) {
 void request_resend() {
 	serial_writestr_P(PSTR("Resend:"));
 	serwrite_uint8(next_target.N);
-	serial_writestr_P(PSTR("\n"));
+	serial_writechar('\n');
 }
 
diff --git a/mendel/serial.c b/mendel/serial.c
index 767bdeb..13703c2 100644
--- a/mendel/serial.c
+++ b/mendel/serial.c
@@ -163,19 +163,21 @@ void serial_writestr(uint8_t *data)
 
 /*
 	Write from FLASH
-*/
 
-void serial_writechar_P(PGM_P data)
-{
-	serial_writechar(pgm_read_byte(data));
-}
+	Extensions to output flash memory pointers. This prevents the data to
+	become part of the .data segment instead of the .code segment. That means
+	less memory is consumed for multi-character writes.
+
+	For single character writes (i.e. '\n' instead of "\n"), using
+	serial_writechar() directly is the better choice.
+*/
 
 void serial_writeblock_P(PGM_P data, int datalen)
 {
 	int i;
 
 	for (i = 0; i < datalen; i++)
-		serial_writechar_P(&data[i]);
+		serial_writechar(pgm_read_byte(&data[i]));
 }
 
 void serial_writestr_P(PGM_P data)
diff --git a/mendel/serial.h b/mendel/serial.h
index 1f30c2c..73a7b18 100644
--- a/mendel/serial.h
+++ b/mendel/serial.h
@@ -24,7 +24,6 @@ void serial_writeblock(void *data, int datalen);
 void serial_writestr(uint8_t *data);
 
 // write from flash
-void serial_writechar_P(PGM_P data);
 void serial_writeblock_P(PGM_P data, int datalen);
 void serial_writestr_P(PGM_P data);