Optimize LCD string/char printing

Marlin/ultralcd_impl_DOGM.h

   }
 }
 
-char lcd_print(char c) {
+void lcd_print(char c) {
+  if ((c > 0) && (c <= LCD_STR_SPECIAL_MAX)) {
+    u8g.setFont(FONT_SPECIAL_NAME);
+    u8g.print(c);
+    lcd_setFont(currentfont);
+  }
+  else charset_mapper(c);
+}
+
+char lcd_print_and_count(char c) {
   if ((c > 0) && (c <= LCD_STR_SPECIAL_MAX)) {
     u8g.setFont(FONT_SPECIAL_NAME);
     u8g.print(c);
     lcd_setFont(currentfont);
     return 1;
-  } else {
-    return charset_mapper(c);
   }
+  else return charset_mapper(c);
 }
 
-char lcd_print(const char* str) {
-  int i = 0;
-  char c, n = 0;
-  while ((c = str[i++])) n += lcd_print(c);
-  return n;
+void lcd_print(const char* str) {
+  for (uint8_t i = 0; char c = str[i]; ++i) lcd_print(c);
 }
 
-// Needed for Arduino < 1.0.0
-char lcd_printPGM(const char* str) {
-  char c, n = 0;
-  while ((c = pgm_read_byte(str++))) n += lcd_print(c);
-  return n;
+/* Arduino < 1.0.0 is missing a function to print PROGMEM strings, so we need to implement our own */
+void lcd_printPGM(const char* str) {
+  for (; char c = pgm_read_byte(str); ++str) lcd_print(c);
 }
 
 // Initialize or re-initializw the LCD
     lcd_printPGM(pstr);
   else {
     if (!axis_homed[axis])
-      lcd_printPGM(PSTR("?"));
+      u8g.print('?');
     else {
       #if DISABLED(DISABLE_REDUCED_ACCURACY_WARNING)
         if (!axis_known_position[axis])
-          lcd_printPGM(PSTR(" "));
+          u8g.print(' ');
         else
       #endif
       lcd_printPGM(pstr);
     int per = ((fanSpeeds[0] + 1) * 100) / 256;
     if (per) {
       lcd_print(itostr3(per));
-      lcd_print('%');
+      u8g.print('%');
     }
   #endif
 
   lcd_setFont(FONT_STATUSMENU);
   u8g.setPrintPos(12, 49);
   lcd_print(itostr3(feedrate_percentage));
-  lcd_print('%');
+  u8g.print('%');
 
   // Status line
   #if ENABLED(USE_SMALL_INFOFONT)
       lcd_print(ftostr12ns(filament_width_meas));
       lcd_printPGM(PSTR(" factor:"));
       lcd_print(itostr3(100.0 * volumetric_multiplier[FILAMENT_SENSOR_EXTRUDER_NUM]));
-      lcd_print('%');
+      u8g.print('%');
     }
   #endif
 }
 
       if (center && !valstr) {
         int8_t pad = (LCD_WIDTH - lcd_strlen_P(pstr)) / 2;
-        while (--pad >= 0) { lcd_print(' '); n--; }
+        while (--pad >= 0) { u8g.print(' '); n--; }
       }
       while (n > 0 && (c = pgm_read_byte(pstr))) {
-        n -= lcd_print(c);
+        n -= lcd_print_and_count(c);
         pstr++;
       }
       if (valstr) while (n > 0 && (c = *valstr)) {
-        n -= lcd_print(c);
+        n -= lcd_print_and_count(c);
         valstr++;
       }
-      while (n-- > 0) lcd_print(' ');
+      while (n-- > 0) u8g.print(' ');
     }
 
   #endif // LCD_INFO_MENU || FILAMENT_CHANGE_FEATURE
     lcd_implementation_mark_as_selected(row, isSelected);
 
     while (c = pgm_read_byte(pstr)) {
-      n -= lcd_print(c);
+      n -= lcd_print_and_count(c);
       pstr++;
     }
-    while (n--) lcd_print(' ');
+    while (n--) u8g.print(' ');
     u8g.setPrintPos(LCD_PIXEL_WIDTH - (DOG_CHAR_WIDTH), (row + 1) * (DOG_CHAR_HEIGHT));
     lcd_print(post_char);
-    lcd_print(' ');
+    u8g.print(' ');
   }
 
   // Macros for specific types of menu items
     lcd_implementation_mark_as_selected(row, isSelected);
 
     while (c = pgm_read_byte(pstr)) {
-      n -= lcd_print(c);
+      n -= lcd_print_and_count(c);
       pstr++;
     }
-    lcd_print(':');
-    while (n--) lcd_print(' ');
+    u8g.print(':');
+    while (n--) u8g.print(' ');
     u8g.setPrintPos(LCD_PIXEL_WIDTH - (DOG_CHAR_WIDTH) * vallen, (row + 1) * (DOG_CHAR_HEIGHT));
     if (pgm)  lcd_printPGM(data);  else  lcd_print((char*)data);
   }
     u8g.setPrintPos(0, rowHeight + kHalfChar);
     lcd_printPGM(pstr);
     if (value != NULL) {
-      lcd_print(':');
+      u8g.print(':');
       u8g.setPrintPos((lcd_width - 1 - vallen) * char_width, rows * rowHeight + kHalfChar);
       lcd_print(value);
     }
 
       if (isDir) lcd_print(LCD_STR_FOLDER[0]);
       while ((c = *filename)) {
-        n -= lcd_print(c);
+        n -= lcd_print_and_count(c);
         filename++;
       }
-      while (n--) lcd_print(' ');
+      while (n--) u8g.print(' ');
     }
 
     #define lcd_implementation_drawmenu_sdfile(sel, row, pstr, filename, longFilename) _drawmenu_sd(sel, row, pstr, filename, longFilename, false)

Marlin/ultralcd_impl_HD44780.h

 static void lcd_implementation_clear() { lcd.clear(); }
 
 /* Arduino < 1.0.0 is missing a function to print PROGMEM strings, so we need to implement our own */
-char lcd_printPGM(const char* str) {
-  char c, n = 0;
-  while ((c = pgm_read_byte(str++))) n += charset_mapper(c);
-  return n;
+void lcd_printPGM(const char *str) {
+  for (; char c = pgm_read_byte(str); ++str) charset_mapper(c);
 }
 
-char lcd_print(const char* str) {
-  char c, n = 0;
-  unsigned char i = 0;
-  while ((c = str[i++])) n += charset_mapper(c);
-  return n;
+void lcd_print(const char* str) {
+  for (uint8_t i = 0; char c = str[i]; ++i) charset_mapper(c);
 }
 
-unsigned lcd_print(char c) { return charset_mapper(c); }
+void lcd_print(char c) { charset_mapper(c); }
 
 #if ENABLED(SHOW_BOOTSCREEN)
 
     lcd_printPGM(pstr);
   else {
     if (!axis_homed[axis])
-      lcd_printPGM(PSTR("?"));
+      lcd.print('?');
     else {
       #if DISABLED(DISABLE_REDUCED_ACCURACY_WARNING)
         if (!axis_known_position[axis])
-          lcd_printPGM(PSTR(" "));
+          lcd.print(' ');
         else
       #endif
       lcd_printPGM(pstr);
         _draw_axis_label(X_AXIS, PSTR(MSG_X), blink);
         lcd.print(ftostr4sign(current_position[X_AXIS]));
 
-        lcd_printPGM(PSTR(" "));
+        lcd.print(' ');
 
         _draw_axis_label(Y_AXIS, PSTR(MSG_Y), blink);
         lcd.print(ftostr4sign(current_position[Y_AXIS]));
         while (--pad >= 0) { lcd.print(' '); n--; }
       }
       while (n > 0 && (c = pgm_read_byte(pstr))) {
-        n -= lcd_print(c);
+        n -= charset_mapper(c);
         pstr++;
       }
       if (valstr) while (n > 0 && (c = *valstr)) {
-        n -= lcd_print(c);
+        n -= charset_mapper(c);
         valstr++;
       }
       while (n-- > 0) lcd.print(' ');
     lcd.setCursor(0, row);
     lcd.print(sel ? pre_char : ' ');
     while ((c = pgm_read_byte(pstr)) && n > 0) {
-      n -= lcd_print(c);
+      n -= charset_mapper(c);
       pstr++;
     }
     while (n--) lcd.print(' ');
     lcd.setCursor(0, row);
     lcd.print(sel ? pre_char : ' ');
     while ((c = pgm_read_byte(pstr)) && n > 0) {
-      n -= lcd_print(c);
+      n -= charset_mapper(c);
       pstr++;
     }
     lcd.print(':');
     lcd.setCursor(0, row);
     lcd.print(sel ? pre_char : ' ');
     while ((c = pgm_read_byte(pstr)) && n > 0) {
-      n -= lcd_print(c);
+      n -= charset_mapper(c);
       pstr++;
     }
     lcd.print(':');
         longFilename[n] = '\0';
       }
       while ((c = *filename) && n > 0) {
-        n -= lcd_print(c);
+        n -= charset_mapper(c);
         filename++;
       }
       while (n--) lcd.print(' ');