Use macros where possible

Apply `constrain`, `NOMORE`, `NOLESS` and `CRITICAL_SECTION` macros
wherever possible.

Marlin/Marlin_main.cpp

 
               apply_rotation_xyz(plan_bed_level_matrix, x_tmp, y_tmp, z_tmp);
 
-              if (eqnBVector[ind] - z_tmp < min_diff)
-                min_diff = eqnBVector[ind] - z_tmp;
+              NOMORE(min_diff, eqnBVector[ind] - z_tmp);
 
               if (diff >= 0.0)
                 SERIAL_PROTOCOLPGM(" +");   // Include + for column alignment
    */
   inline void gcode_M405() {
     if (code_seen('D')) meas_delay_cm = code_value();
-    if (meas_delay_cm > MAX_MEASUREMENT_DELAY) meas_delay_cm = MAX_MEASUREMENT_DELAY;
+    NOMORE(meas_delay_cm, MAX_MEASUREMENT_DELAY);
 
     if (delay_index2 == -1) { //initialize the ring buffer if it has not been done since startup
       int temp_ratio = widthFil_to_size_ratio();

Marlin/SdBaseFile.cpp

   if (!isOpen() || !(flags_ & O_READ)) goto fail;
 
   // max bytes left in file
-  if (nbyte >= (fileSize_ - curPosition_)) {
-    nbyte = fileSize_ - curPosition_;
-  }
+  NOMORE(nbyte, fileSize_ - curPosition_);
+
   // amount left to read
   toRead = nbyte;
   while (toRead > 0) {
     uint16_t n = toRead;
 
     // amount to be read from current block
-    if (n > (512 - offset)) n = 512 - offset;
+    NOMORE(n, 512 - offset);
 
     // no buffering needed if n == 512
     if (n == 512 && block != vol_->cacheBlockNumber()) {
     uint16_t n = 512 - blockOffset;
 
     // lesser of space and amount to write
-    if (n > nToWrite) n = nToWrite;
+    NOMORE(n, nToWrite);
 
     // block for data write
     uint32_t block = vol_->clusterStartBlock(curCluster_) + blockOfCluster;

Marlin/SdVolume.cpp

 
   for (uint32_t lba = fatStartBlock_; todo; todo -= n, lba++) {
     if (!cacheRawBlock(lba, CACHE_FOR_READ)) return -1;
-    if (todo < n) n = todo;
+    NOMORE(n, todo);
     if (fatType_ == 16) {
       for (uint16_t i = 0; i < n; i++) {
         if (cacheBuffer_.fat16[i] == 0) free++;

Marlin/planner.cpp

       block_t* block = &block_buffer[block_index];
       if (block->steps[X_AXIS] || block->steps[Y_AXIS] || block->steps[Z_AXIS]) {
         float se = (float)block->steps[E_AXIS] / block->step_event_count * block->nominal_speed; // mm/sec;
-        if (se > high) high = se;
+        NOLESS(high, se);
       }
       block_index = next_block_index(block_index);
     }

Marlin/qr_solve.cpp

   double value = r8_abs(a[0 + 0 * m]);
   for (int j = 0; j < n; j++) {
     for (int i = 0; i < m; i++) {
-      if (value < r8_abs(a[i + j * m]))
-        value = r8_abs(a[i + j * m]);
+      NOLESS(value, r8_abs(a[i + j * m]));
     }
   }
   return value;

Marlin/servo.cpp

 
 void Servo::write(int value) {
   if (value < MIN_PULSE_WIDTH) { // treat values less than 544 as angles in degrees (valid values in microseconds are handled as microseconds)
-    if (value < 0) value = 0;
-    if (value > 180) value = 180;
-    value = map(value, 0, 180, SERVO_MIN(),  SERVO_MAX());
+    value = map(constrain(value, 0, 180), 0, 180, SERVO_MIN(), SERVO_MAX());
   }
   this->writeMicroseconds(value);
 }
   // calculate and store the values for the given channel
   byte channel = this->servoIndex;
   if (channel < MAX_SERVOS) {  // ensure channel is valid
-    if (value < SERVO_MIN())   // ensure pulse width is valid
-      value = SERVO_MIN();
-    else if (value > SERVO_MAX())
-      value = SERVO_MAX();
-
-    value = value - TRIM_DURATION;
+    // ensure pulse width is valid
+    value = constrain(value, SERVO_MIN(), SERVO_MAX()) - TRIM_DURATION;
     value = usToTicks(value);  // convert to ticks after compensating for interrupt overhead - 12 Aug 2009
 
-    uint8_t oldSREG = SREG;
-    cli();
+    CRITICAL_SECTION_START;
     servo_info[channel].ticks = value;
-    SREG = oldSREG;
+    CRITICAL_SECTION_END;
   }
 }
 

Marlin/temperature.cpp

       // the nominal filament diameter then square it to get an area
       meas_shift_index = constrain(meas_shift_index, 0, MAX_MEASUREMENT_DELAY);
       float vm = pow((measurement_delay[meas_shift_index] + 100.0) / 100.0, 2);
-      if (vm < 0.01) vm = 0.01;
+      NOLESS(vm, 0.01);
       volumetric_multiplier[FILAMENT_SENSOR_EXTRUDER_NUM] = vm;
     }
   #endif //FILAMENT_SENSOR
   int widthFil_to_size_ratio() {
     float temp = filament_width_meas;
     if (temp < MEASURED_LOWER_LIMIT) temp = filament_width_nominal;  //assume sensor cut out
-    else if (temp > MEASURED_UPPER_LIMIT) temp = MEASURED_UPPER_LIMIT;
+    else NOMORE(temp, MEASURED_UPPER_LIMIT);
     return filament_width_nominal / temp * 100;
   }
 

Marlin/ultralcd.cpp

     encoderRateMultiplierEnabled = false; \
     if (encoderPosition > 0x8000) encoderPosition = 0; \
     uint8_t encoderLine = encoderPosition / ENCODER_STEPS_PER_MENU_ITEM; \
-    if (encoderLine < currentMenuViewOffset) currentMenuViewOffset = encoderLine; \
+    NOMORE(currentMenuViewOffset, encoderLine); \
     uint8_t _lineNr = currentMenuViewOffset, _menuItemNr; \
     bool wasClicked = LCD_CLICKED, itemSelected; \
     for (uint8_t _drawLineNr = 0; _drawLineNr < LCD_HEIGHT; _drawLineNr++, _lineNr++) { \
   if (encoderPosition != 0) {
     refresh_cmd_timeout();
     current_position[axis] += float((int)encoderPosition) * move_menu_scale;
-    if (min_software_endstops && current_position[axis] < min) current_position[axis] = min;
-    if (max_software_endstops && current_position[axis] > max) current_position[axis] = max;
+    if (min_software_endstops) NOLESS(current_position[axis], min);
+    if (max_software_endstops) NOMORE(current_position[axis], max);
     encoderPosition = 0;
     if (movesplanned() <= 3)
       line_to_current(axis);
     if (encoderPosition != 0) {
       refresh_cmd_timeout();
       current_position[Z_AXIS] += float((int)encoderPosition) * MBL_Z_STEP;
-      if (min_software_endstops && current_position[Z_AXIS] < Z_MIN_POS) current_position[Z_AXIS] = Z_MIN_POS;
-      if (max_software_endstops && current_position[Z_AXIS] > Z_MAX_POS) current_position[Z_AXIS] = Z_MAX_POS;
+      if (min_software_endstops) NOLESS(current_position[Z_AXIS], Z_MIN_POS);
+      if (max_software_endstops) NOMORE(current_position[Z_AXIS], Z_MAX_POS);
       encoderPosition = 0;
       line_to_current(Z_AXIS);
       lcdDrawUpdate = 2;