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fabriceofabriceo
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SchedulerARMAVR
Proposal for including a new version of the Scheduler.h in the Arduino libraries, including asm code for AVR task switch. resulting file compatible with both ARM and AVR.
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‎libraries/SchedulerARMAVR/SchedulerARMAVR.cpp

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/*
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* Copyright (C) 2012 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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/* modified by Fabrice Oudert 8 Jan 2013
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* including spcific code for compatibility with AVR platform (not 2560)
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* Scheduler library package available on google Code here:
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* https://code.google.com/p/arduino-scoop-cooperative-scheduler-arm-avr/
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*/
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#include "SchedulerARMAVR.h"
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extern "C" {
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#if defined(__arm__)
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#define NUM_REGS (8+1+1) // r4-r11, sp, pc
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#elif defined(__AVR_3_BYTE_PC__)
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#error "not compatible with atmega256x, sorry ! please provide ideas on the arduino.cc forum"
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#else
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#define NUM_REGS (8+1+1+1) // r2-r17, sp, pc, r28-r29
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#endif
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typedef struct CoopTask {
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#ifdef __arm__
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uint32_t regs[NUM_REGS];
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#else
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uint16_t regs[NUM_REGS];
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#endif
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void* stackPtr;
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struct CoopTask* next;
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struct CoopTask* prev;
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} CoopTask;
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static CoopTask *cur = 0;
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static CoopTask* __attribute__((noinline)) coopSchedule(char taskDied) {
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CoopTask* next = cur->next;
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if (taskDied) {
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// Halt if last task died.
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if (next == cur)
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while (1)
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;
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// Delete task
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if (cur->stackPtr)
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free(cur->stackPtr);
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cur->next->prev = cur->prev;
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cur->prev->next = cur->next;
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free(cur);
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}
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cur = next;
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#ifdef __AVR__
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asm volatile ("movw r30, %[reg]" : : [reg] "r" (next));
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asm volatile ("ldd r5, Z+3");
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asm volatile ("ldd r6, Z+4");
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asm volatile ("ldd r7, Z+5");
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asm volatile ("ldd r8, Z+6");
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asm volatile ("ldd r9, Z+7");
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asm volatile ("ldd r10, Z+8");
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asm volatile ("ldd r11, Z+9");
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asm volatile ("ldd r12, Z+10");
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asm volatile ("ldd r13, Z+11");
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asm volatile ("ldd r14, Z+12");
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asm volatile ("ldd r15, Z+13");
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asm volatile ("ldd r16, Z+14");
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asm volatile ("ldd r17, Z+15");
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asm volatile ("ldd r2, Z+16"); // restore SP
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asm volatile ("ldd r3, Z+17");
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asm volatile ("in r4, 0x3f"); // save SREG
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asm volatile ("cli "); // just to be safe on playing with stack ptr :) (useless with xmega)
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asm volatile ("out 0x3e, r3"); // SPH
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asm volatile ("out 0x3d, r2"); // SPL
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asm volatile ("out 0x3f, r4"); // restore SREG asap (same approach as in setjmp.S credit to Marek Michalkiewicz)
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asm volatile ("ldd r2, Z+0");
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asm volatile ("ldd r3, Z+1");
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asm volatile ("ldd r4, Z+2");
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asm volatile ("ldd r28, Z+20"); // get previous R28,R29
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asm volatile ("ldd r29, Z+21");
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asm volatile ("ldd __tmp_reg__, Z+18"); // return low
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asm volatile ("ldd r31, Z+19"); // return hi
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asm volatile ("mov r30,__tmp_reg__");
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asm volatile ("ijmp"); // jump back to task return adress
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#endif
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return cur; // just to avoid warning !
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}
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static void __attribute__((naked)) __attribute__((noinline)) coopTaskStart(void) {
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#ifdef __arm__
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asm (
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"mov r0, r5;"
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"blx r4;"
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"mov r0, #1;"
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"bl coopSchedule;"
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"ldmia r0, {r4-r12, lr};"
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"mov sp, r12;"
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"bx lr;"
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);
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#else
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asm volatile ("movw r30,r2"); // get original taskF parameter
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asm volatile ("movw r24,r4"); // get original taskData parameter
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asm volatile ("icall"); // call taskF
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asm volatile ("ldi r24,1"); // task died
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asm volatile ("rjmp coopSchedule"); // get next task pointer
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#endif
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}
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static void __attribute__((naked)) __attribute__((noinline)) coopDoYield(CoopTask* curTask) {
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#ifdef __arm__
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asm (
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"mov r12, sp;"
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"stmia r0, {r4-r12, lr};"
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"mov r0, #0;"
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"bl coopSchedule;"
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"ldmia r0, {r4-r12, lr};"
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"mov sp, r12;"
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"bx lr;"
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);
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#else
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asm volatile ("movw r30, %[cur]" : : [cur] "r" (curTask));
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asm volatile ("std Z+0, r2"); // save register in current cooptask structure
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asm volatile ("std Z+1, r3");
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asm volatile ("std Z+2, r4");
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asm volatile ("std Z+3, r5");
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asm volatile ("std Z+4, r6");
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asm volatile ("std Z+5, r7");
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asm volatile ("std Z+6, r8");
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asm volatile ("std Z+7, r9");
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asm volatile ("std Z+8, r10");
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asm volatile ("std Z+9, r11");
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asm volatile ("std Z+10, r12");
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asm volatile ("std Z+11, r13");
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asm volatile ("std Z+12, r14");
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asm volatile ("std Z+13, r15");
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asm volatile ("std Z+14, r16");
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asm volatile ("std Z+15, r17");
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asm volatile ("pop r3"); // return adresse = yield caller /// NOT COMPATIBLE 2560
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asm volatile ("pop r2");
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asm volatile ("std Z+18, r2"); // store return adress
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asm volatile ("std Z+19, r3");
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asm volatile ("in r2, 0x3d"); // SPL
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asm volatile ("in r3, 0x3e"); // SPH
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asm volatile ("std Z+16, r2");
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asm volatile ("std Z+17, r3");
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asm volatile ("std Z+20, r28");
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asm volatile ("std Z+21, r29");
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asm volatile ("ldi r24, 0");
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asm volatile ("rjmp coopSchedule"); // get next task pointer
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#endif
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}
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static int coopInit(void) {
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CoopTask* task;
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task = reinterpret_cast<CoopTask *>(malloc(sizeof(CoopTask)));
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if (!task)
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return 0;
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task->next = task;
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task->prev = task;
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task->stackPtr = 0;
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cur = task;
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return 1;
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}
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static int coopSpawn(SchedulerParametricTask taskF, void* taskData, uint32_t stackSz) {
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uint8_t *stack = (uint8_t*)malloc(stackSz);
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if (!stack)
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return 0;
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CoopTask *task = reinterpret_cast<CoopTask *>(malloc(sizeof(CoopTask)));
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if (!task) {
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free(stack);
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return 0;
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}
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task->stackPtr = stack;
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task->regs[0] = (uint32_t) taskF;
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task->regs[1] = (uint32_t) taskData;
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task->regs[8] = ((uint32_t)(stack + stackSz))
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#ifdef __arm__
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& ~7
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#endif
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;
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task->regs[9] = (uint32_t) & coopTaskStart;
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task->prev = cur;
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task->next = cur->next;
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cur->next->prev = task;
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cur->next = task;
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// These are here so compiler is sure that function is
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// referenced in both variants (cancels a warning)
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if (stackSz == 0xFFFFFFFF)
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coopSchedule(0);
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if (stackSz == 0xFFFFFFFE)
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coopSchedule(1);
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return 1;
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}
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void yield(void) {
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coopDoYield(cur);
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}
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}; // extern "C"
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SchedulerClass::SchedulerClass() {
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coopInit();
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}
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static void startLoopHelper(void *taskData) {
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SchedulerTask task = reinterpret_cast<SchedulerTask>(taskData);
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while (true)
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task();
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}
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void SchedulerClass::startLoop(SchedulerTask task, uint32_t stackSize) {
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coopSpawn(startLoopHelper, reinterpret_cast<void *>(task), stackSize);
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}
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static void startTaskHelper(void *taskData) {
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SchedulerTask task = reinterpret_cast<SchedulerTask>(taskData);
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task();
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}
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void SchedulerClass::start(SchedulerTask task, uint32_t stackSize) {
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coopSpawn(startTaskHelper, reinterpret_cast<void *>(task), stackSize);
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}
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void SchedulerClass::start(SchedulerParametricTask task, void *taskData, uint32_t stackSize) {
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coopSpawn(task, taskData, stackSize);
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}
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// added for some level of compatibility with Arduino < 150
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void SchedulerClass::delay(uint32_t ms) {
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uint32_t end = millis() + ms;
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while (millis() < end) yield();
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}
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SchedulerClass Scheduler;
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‎libraries/SchedulerARMAVR/SchedulerARMAVR.h

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/*
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* Copyright (C) 2012 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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/* modified by Fabrice Oudert 8 Jan 2013
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* including spcific code for compatibility with AVR platform (not atmega2560)
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* Scheduler library package available on google Code here:
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* https://code.google.com/p/arduino-scoop-cooperative-scheduler-arm-avr/
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*/
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#ifndef _SCHEDULDER_H_
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#define _SCHEDULDER_H_
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#include <Arduino.h>
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extern "C" {
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typedef void (*SchedulerTask)(void);
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typedef void (*SchedulerParametricTask)(void *);
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#if ARDUINO < 150
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void yield(void); // define a global yield function
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#warning "library calls to Arduino delay doesnt contain yield() and might block scheduler during this delay"
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#endif
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}
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#ifndef yieldPROTECT
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#define yieldPROTECT() static uint8_t __yieldProtect = 0; \
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uint8_t* __temp __attribute__((__cleanup__(__yieldUnprotect))) = & __yieldProtect; \
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while (__yieldProtect) yield(); __yieldProtect = 1;
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void inline __yieldUnprotect(uint8_t* *__s) { uint8_t* staticFlag = *__s; *staticFlag = 0; };
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#endif
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#ifndef yieldATOMIC
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#define yieldATOMIC for ( uint8_t __temp __attribute__((__cleanup__(__decYieldAtomic))) = __incYieldAtomic(); __temp ; __temp = 0 )
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static volatile uint8_t __yieldAtomic = 0;
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void inline __decYieldAtomic(const uint8_t *__s) { --__yieldAtomic; }
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uint8_t inline __incYieldAtomic(void) { ++__yieldAtomic; return 1; }
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#endif
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#ifdef __AVR__
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#define SchedulerDefaultStack 256 // proposed value, might be too low fo complex application or too high if not needed ... to be experimented by user
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#else
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#define SchedulerDefaultStack 1024 // original value , probably too much for most usage, but lot of memory on SAM
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#endif
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class SchedulerClass {
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public:
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SchedulerClass();
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static void startLoop(SchedulerTask task, uint32_t stackSize = SchedulerDefaultStack);
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static void start(SchedulerTask task, uint32_t stackSize = SchedulerDefaultStack);
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static void start(SchedulerParametricTask task, void *data, uint32_t stackSize = SchedulerDefaultStack);
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static void delay(uint32_t ms);
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static void yield() { ::yield(); };
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};
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extern SchedulerClass Scheduler;
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#endif
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