From e8701195e66f2d27ffe17fb514eae8173795aaf7 Mon Sep 17 00:00:00 2001
From: Georgiy Bondarenko <69736697+nehilo@users.noreply.github.com>
Date: Thu, 4 Mar 2021 22:54:23 +0500
Subject: Initial commit

---
 Marlin/src/HAL/shared/Delay.h | 161 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 161 insertions(+)
 create mode 100644 Marlin/src/HAL/shared/Delay.h

(limited to 'Marlin/src/HAL/shared/Delay.h')

diff --git a/Marlin/src/HAL/shared/Delay.h b/Marlin/src/HAL/shared/Delay.h
new file mode 100644
index 0000000..a48f3f7
--- /dev/null
+++ b/Marlin/src/HAL/shared/Delay.h
@@ -0,0 +1,161 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+/**
+ * Busy wait delay cycles routines:
+ *
+ *  DELAY_CYCLES(count): Delay execution in cycles
+ *  DELAY_NS(count): Delay execution in nanoseconds
+ *  DELAY_US(count): Delay execution in microseconds
+ */
+
+#include "../../core/macros.h"
+
+#if defined(__arm__) || defined(__thumb__)
+
+  #if __CORTEX_M == 7
+
+    // Cortex-M3 through M7 can use the cycle counter of the DWT unit
+    // https://www.anthonyvh.com/2017/05/18/cortex_m-cycle_counter/
+
+    FORCE_INLINE static void enableCycleCounter() {
+      CoreDebug->DEMCR |= CoreDebug_DEMCR_TRCENA_Msk;
+
+      #if __CORTEX_M == 7
+        DWT->LAR = 0xC5ACCE55; // Unlock DWT on the M7
+      #endif
+
+      DWT->CYCCNT = 0;
+      DWT->CTRL |= DWT_CTRL_CYCCNTENA_Msk;
+    }
+
+    FORCE_INLINE volatile uint32_t getCycleCount() { return DWT->CYCCNT; }
+
+    FORCE_INLINE static void DELAY_CYCLES(const uint32_t x) {
+      const uint32_t endCycles = getCycleCount() + x;
+      while (PENDING(getCycleCount(), endCycles)) {}
+    }
+
+  #else
+
+    // https://blueprints.launchpad.net/gcc-arm-embedded/+spec/delay-cycles
+
+    #define nop() __asm__ __volatile__("nop;\n\t":::)
+
+    FORCE_INLINE static void __delay_4cycles(uint32_t cy) { // +1 cycle
+      #if ARCH_PIPELINE_RELOAD_CYCLES < 2
+        #define EXTRA_NOP_CYCLES A("nop")
+      #else
+        #define EXTRA_NOP_CYCLES ""
+      #endif
+
+      __asm__ __volatile__(
+        A(".syntax unified") // is to prevent CM0,CM1 non-unified syntax
+        L("1")
+        A("subs %[cnt],#1")
+        EXTRA_NOP_CYCLES
+        A("bne 1b")
+        : [cnt]"+r"(cy)   // output: +r means input+output
+        :                 // input:
+        : "cc"            // clobbers:
+      );
+    }
+
+    // Delay in cycles
+    FORCE_INLINE static void DELAY_CYCLES(uint32_t x) {
+
+      if (__builtin_constant_p(x)) {
+        #define MAXNOPS 4
+
+        if (x <= (MAXNOPS)) {
+          switch (x) { case 4: nop(); case 3: nop(); case 2: nop(); case 1: nop(); }
+        }
+        else { // because of +1 cycle inside delay_4cycles
+          const uint32_t rem = (x - 1) % (MAXNOPS);
+          switch (rem) { case 3: nop(); case 2: nop(); case 1: nop(); }
+          if ((x = (x - 1) / (MAXNOPS)))
+            __delay_4cycles(x); // if need more then 4 nop loop is more optimal
+        }
+        #undef MAXNOPS
+      }
+      else if ((x >>= 2))
+        __delay_4cycles(x);
+    }
+    #undef nop
+
+  #endif
+
+#elif defined(__AVR__)
+
+  #define nop() __asm__ __volatile__("nop;\n\t":::)
+
+  FORCE_INLINE static void __delay_4cycles(uint8_t cy) {
+    __asm__ __volatile__(
+      L("1")
+      A("dec %[cnt]")
+      A("nop")
+      A("brne 1b")
+      : [cnt] "+r"(cy)  // output: +r means input+output
+      :                 // input:
+      : "cc"            // clobbers:
+    );
+  }
+
+  // Delay in cycles
+  FORCE_INLINE static void DELAY_CYCLES(uint16_t x) {
+
+    if (__builtin_constant_p(x)) {
+      #define MAXNOPS 4
+
+      if (x <= (MAXNOPS)) {
+        switch (x) { case 4: nop(); case 3: nop(); case 2: nop(); case 1: nop(); }
+      }
+      else {
+        const uint32_t rem = (x) % (MAXNOPS);
+        switch (rem) { case 3: nop(); case 2: nop(); case 1: nop(); }
+        if ((x = (x) / (MAXNOPS)))
+          __delay_4cycles(x); // if need more then 4 nop loop is more optimal
+      }
+
+      #undef MAXNOPS
+    }
+    else if ((x >>= 2))
+      __delay_4cycles(x);
+  }
+  #undef nop
+
+#elif defined(__PLAT_LINUX__) || defined(ESP32)
+
+  // specified inside platform
+
+#else
+
+  #error "Unsupported MCU architecture"
+
+#endif
+
+// Delay in nanoseconds
+#define DELAY_NS(x) DELAY_CYCLES((x) * ((F_CPU) / 1000000UL) / 1000UL)
+
+// Delay in microseconds
+#define DELAY_US(x) DELAY_CYCLES((x) * ((F_CPU) / 1000000UL))
-- 
cgit v1.2.3