2 * FreeRTOS Kernel V10.0.0
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3 * Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software. If you wish to use our Amazon
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14 * FreeRTOS name, please do so in a fair use way that does not cause confusion.
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16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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18 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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19 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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20 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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23 * http://www.FreeRTOS.org
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24 * http://aws.amazon.com/freertos
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26 * 1 tab == 4 spaces!
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29 /*-----------------------------------------------------------
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30 * Implementation of functions defined in portable.h for the SH2A port.
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31 *----------------------------------------------------------*/
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33 /* Scheduler includes. */
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34 #include "FreeRTOS.h"
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37 /* Library includes. */
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40 /*-----------------------------------------------------------*/
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42 /* The SR assigned to a newly created task. The only important thing in this
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43 value is for all interrupts to be enabled. */
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44 #define portINITIAL_SR ( 0UL )
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46 /* Dimensions the array into which the floating point context is saved.
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47 Allocate enough space for FPR0 to FPR15, FPUL and FPSCR, each of which is 4
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48 bytes big. If this number is changed then the 72 in portasm.src also needs
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50 #define portFLOP_REGISTERS_TO_STORE ( 18 )
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51 #define portFLOP_STORAGE_SIZE ( portFLOP_REGISTERS_TO_STORE * 4 )
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53 #if( configSUPPORT_DYNAMIC_ALLOCATION == 0 )
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54 #error configSUPPORT_DYNAMIC_ALLOCATION must be 1 to use this port.
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57 /*-----------------------------------------------------------*/
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60 * The TRAPA handler used to force a context switch.
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62 void vPortYield( void );
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65 * Function to start the first task executing - defined in portasm.src.
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67 extern void vPortStartFirstTask( void );
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70 * Obtains the current GBR value - defined in portasm.src.
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72 extern uint32_t ulPortGetGBR( void );
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74 /*-----------------------------------------------------------*/
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77 * See header file for description.
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79 StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
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81 /* Mark the end of the stack - used for debugging only and can be removed. */
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82 *pxTopOfStack = 0x11111111UL;
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84 *pxTopOfStack = 0x22222222UL;
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86 *pxTopOfStack = 0x33333333UL;
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90 *pxTopOfStack = portINITIAL_SR;
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94 *pxTopOfStack = ( uint32_t ) pxCode;
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102 *pxTopOfStack = 14;
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106 *pxTopOfStack = 13;
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110 *pxTopOfStack = 12;
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114 *pxTopOfStack = 11;
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118 *pxTopOfStack = 10;
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142 *pxTopOfStack = ( uint32_t ) pvParameters;
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162 *pxTopOfStack = 16;
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166 *pxTopOfStack = 17;
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170 *pxTopOfStack = ulPortGetGBR();
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172 /* GBR = global base register.
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173 VBR = vector base register.
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174 TBR = jump table base register.
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175 R15 is the stack pointer. */
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177 return pxTopOfStack;
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179 /*-----------------------------------------------------------*/
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181 BaseType_t xPortStartScheduler( void )
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183 extern void vApplicationSetupTimerInterrupt( void );
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185 /* Call an application function to set up the timer that will generate the
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186 tick interrupt. This way the application can decide which peripheral to
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187 use. A demo application is provided to show a suitable example. */
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188 vApplicationSetupTimerInterrupt();
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190 /* Start the first task. This will only restore the standard registers and
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191 not the flop registers. This does not really matter though because the only
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192 flop register that is initialised to a particular value is fpscr, and it is
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193 only initialised to the current value, which will still be the current value
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194 when the first task starts executing. */
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195 trapa( portSTART_SCHEDULER_TRAP_NO );
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197 /* Should not get here. */
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200 /*-----------------------------------------------------------*/
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202 void vPortEndScheduler( void )
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204 /* Not implemented as there is nothing to return to. */
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206 /*-----------------------------------------------------------*/
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208 void vPortYield( void )
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210 int32_t lInterruptMask;
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212 /* Ensure the yield trap runs at the same priority as the other interrupts
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213 that can cause a context switch. */
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214 lInterruptMask = get_imask();
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216 /* taskYIELD() can only be called from a task, not an interrupt, so the
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217 current interrupt mask can only be 0 or portKERNEL_INTERRUPT_PRIORITY and
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218 the mask can be set without risk of accidentally lowering the mask value. */
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219 set_imask( portKERNEL_INTERRUPT_PRIORITY );
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221 trapa( portYIELD_TRAP_NO );
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223 /* Restore the interrupt mask to whatever it was previously (when the
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224 function was entered). */
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225 set_imask( ( int ) lInterruptMask );
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227 /*-----------------------------------------------------------*/
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229 BaseType_t xPortUsesFloatingPoint( TaskHandle_t xTask )
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231 uint32_t *pulFlopBuffer;
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232 BaseType_t xReturn;
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233 extern void * volatile pxCurrentTCB;
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235 /* This function tells the kernel that the task referenced by xTask is
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236 going to use the floating point registers and therefore requires the
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237 floating point registers saved as part of its context. */
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239 /* Passing NULL as xTask is used to indicate that the calling task is the
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240 subject task - so pxCurrentTCB is the task handle. */
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241 if( xTask == NULL )
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243 xTask = ( TaskHandle_t ) pxCurrentTCB;
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246 /* Allocate a buffer large enough to hold all the flop registers. */
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247 pulFlopBuffer = ( uint32_t * ) pvPortMalloc( portFLOP_STORAGE_SIZE );
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249 if( pulFlopBuffer != NULL )
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251 /* Start with the registers in a benign state. */
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252 memset( ( void * ) pulFlopBuffer, 0x00, portFLOP_STORAGE_SIZE );
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254 /* The first thing to get saved in the buffer is the FPSCR value -
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255 initialise this to the current FPSCR value. */
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256 *pulFlopBuffer = get_fpscr();
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258 /* Use the task tag to point to the flop buffer. Pass pointer to just
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259 above the buffer because the flop save routine uses a pre-decrement. */
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260 vTaskSetApplicationTaskTag( xTask, ( void * ) ( pulFlopBuffer + portFLOP_REGISTERS_TO_STORE ) );
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270 /*-----------------------------------------------------------*/
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