From b3f52f95c7892d7cb2b0683a9729c0a51845cb75 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gu=C3=B0ni=20M=C3=A1r=20Gilbert?= <gudni.m.g@gmail.com>
Date: Sun, 30 Apr 2023 23:31:16 +0000
Subject: [PATCH] optimisation: only check feedrate if knob is rotated

Guard the feedmultiply code with
lcd_encoder.

if lcd_encoder = 0, then there is no need to check if
feedmultiply should be updated.

Also set lcd_encoder to zero in one line to consume the rotation event.

Change in memory:
Flash: -40 bytes
SRAM: 0 bytes
---
 Firmware/ultralcd.cpp | 49 +++++++++++++++++++------------------------
 1 file changed, 22 insertions(+), 27 deletions(-)

diff --git a/Firmware/ultralcd.cpp b/Firmware/ultralcd.cpp
index a2bfd7bd6..537feb8c9 100644
--- a/Firmware/ultralcd.cpp
+++ b/Firmware/ultralcd.cpp
@@ -693,34 +693,29 @@ void lcd_status_screen()                          // NOT static due to using ins
 {
 	static uint8_t lcd_status_update_delay = 0;
 #ifdef ULTIPANEL_FEEDMULTIPLY
-	// Dead zone at 100% feedrate
-	if ((feedmultiply < 100 && (feedmultiply + lcd_encoder) > 100) ||
-		(feedmultiply > 100 && (feedmultiply + lcd_encoder) < 100))
-	{
-		lcd_encoder = 0;
-		feedmultiply = 100;
-	}
-	if (feedmultiply == 100 && lcd_encoder > ENCODER_FEEDRATE_DEADZONE)
-	{
-		feedmultiply += lcd_encoder - ENCODER_FEEDRATE_DEADZONE;
-		lcd_encoder = 0;
-	}
-	else if (feedmultiply == 100 && lcd_encoder < -ENCODER_FEEDRATE_DEADZONE)
-	{
-		feedmultiply += lcd_encoder + ENCODER_FEEDRATE_DEADZONE;
-		lcd_encoder = 0;
-	}
-	else if (feedmultiply != 100)
-	{
-		feedmultiply += lcd_encoder;
-		lcd_encoder = 0;
-	}
-#endif //ULTIPANEL_FEEDMULTIPLY
+    if (lcd_encoder)
+    {
+        const int16_t initial_feedmultiply = feedmultiply;
+        // Dead zone at 100% feedrate
+        if ((feedmultiply < 100 && (feedmultiply + lcd_encoder) > 100) ||
+            (feedmultiply > 100 && (feedmultiply + lcd_encoder) < 100))
+        {
+            feedmultiply = 100;
+        }
+        else if (feedmultiply == 100 && lcd_encoder > ENCODER_FEEDRATE_DEADZONE) {
+            feedmultiply += lcd_encoder - ENCODER_FEEDRATE_DEADZONE;
+        }
+        else if (feedmultiply == 100 && lcd_encoder < -ENCODER_FEEDRATE_DEADZONE) {
+            feedmultiply += lcd_encoder + ENCODER_FEEDRATE_DEADZONE;
+        }
+        else if (feedmultiply != 100) feedmultiply += lcd_encoder;
 
-	if (feedmultiply < 10)
-		feedmultiply = 10;
-	else if (feedmultiply > 999)
-		feedmultiply = 999;
+        if (initial_feedmultiply != feedmultiply) {
+            feedmultiply = constrain(feedmultiply, 10, 999);
+            lcd_encoder = 0; // Consume rotation event
+        }
+    }
+#endif //ULTIPANEL_FEEDMULTIPLY
 
 	if (lcd_draw_update) {
 		// Update the status screen immediately