From 4ce3fa53a18dc3ffd8f906dc91b99d5f4b4c799c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gu=C3=B0ni=20M=C3=A1r=20Gilbert?= <gudni.m.g@gmail.com>
Date: Fri, 21 Apr 2023 17:42:55 +0000
Subject: [PATCH] Optimise M0/M1 code size

Replace two bool variables with one.

It's not obvious but (!hasP && !hasS) is equal to
!(hasP || hasS)

Note: expiration_time_set = hasP || hasS
Truth table:
|--------------------------------------------------|
| hasP| hasS| (!hasP && !hasS)|  !(hasP || hasS) |
|------|-----|--------------------|-----------------|
|   0    |  0   |               1            |            1           |
|   0    |  1   |               0            |            0           |
|   1    |  0   |               0            |            0           |
|   1    |  1   |               0            |            0           |
|--------------------------------------------------|

Change in memory:
Flash: -36 bytes
SRAM: 0 bytes
---
 Firmware/Marlin_main.cpp | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/Firmware/Marlin_main.cpp b/Firmware/Marlin_main.cpp
index 8a8dc0a51..6b6c662f1 100644
--- a/Firmware/Marlin_main.cpp
+++ b/Firmware/Marlin_main.cpp
@@ -5221,18 +5221,13 @@ void process_commands()
     case 1: {
         const char *src = strchr_pointer + 2;
         codenum = 0;
-        bool hasP = false, hasS = false;
-        if (code_seen('P')) {
-            codenum = code_value_long(); // milliseconds to wait
-            hasP = codenum > 0;
-        }
-        if (code_seen('S')) {
-            codenum = code_value_long() * 1000; // seconds to wait
-            hasS = codenum > 0;
-        }
+        if (code_seen('P')) codenum = code_value_long(); // milliseconds to wait
+        if (code_seen('S')) codenum = code_value_long() * 1000; // seconds to wait
+        bool expiration_time_set = bool(codenum);
+
         while (*src == ' ') ++src;
         custom_message_type = CustomMsg::M0Wait;
-        if (!hasP && !hasS && *src != '\0') {
+        if (!expiration_time_set && *src != '\0') {
             lcd_setstatus(src);
         } else {
             // farmers want to abuse a bug from the previous firmware releases
@@ -5247,7 +5242,7 @@ void process_commands()
         st_synchronize();
         menu_set_block(MENU_BLOCK_STATUS_SCREEN_M0);
         previous_millis_cmd.start();
-        if (codenum > 0 ) {
+        if (expiration_time_set) {
             codenum += _millis();  // keep track of when we started waiting
             KEEPALIVE_STATE(PAUSED_FOR_USER);
             while(_millis() < codenum && !lcd_clicked()) {