2 FreeRTOS.org V4.2.0 - Copyright (C) 2003-2007 Richard Barry.
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4 This file is part of the FreeRTOS distribution.
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6 FreeRTOS is free software; you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 2 of the License, or
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9 (at your option) any later version.
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11 FreeRTOS is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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16 You should have received a copy of the GNU General Public License
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17 along with FreeRTOS; if not, write to the Free Software
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 A special exception to the GPL can be applied should you wish to distribute
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21 a combined work that includes FreeRTOS, without being obliged to provide
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22 the source code for any proprietary components. See the licensing section
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23 of http://www.FreeRTOS.org for full details of how and when the exception
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26 ***************************************************************************
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27 See http://www.FreeRTOS.org for documentation, latest information, license
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28 and contact details. Please ensure to read the configuration and relevant
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29 port sections of the online documentation.
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30 ***************************************************************************
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33 /*-----------------------------------------------------------
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34 * Implementation of functions defined in portable.h for the ST STR91x ARM7
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36 *----------------------------------------------------------*/
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38 /* Library includes. */
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39 #include "91x_lib.h"
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41 /* Standard includes. */
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44 /* Scheduler includes. */
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45 #include "FreeRTOS.h"
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48 /* Constants required to setup the initial stack. */
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49 #ifndef _RUN_TASK_IN_ARM_MODE_
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50 #define portINITIAL_SPSR ( ( portSTACK_TYPE ) 0x3f ) /* System mode, THUMB mode, interrupts enabled. */
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52 #define portINITIAL_SPSR ( ( portSTACK_TYPE ) 0x1f ) /* System mode, ARM mode, interrupts enabled. */
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54 #define portINSTRUCTION_SIZE ( ( portSTACK_TYPE ) 4 )
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56 /* Constants required to handle critical sections. */
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57 #define portNO_CRITICAL_NESTING ( ( unsigned portLONG ) 0 )
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60 /*-----------------------------------------------------------*/
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62 /* Setup the watchdog to generate the tick interrupts. */
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63 static void prvSetupTimerInterrupt( void );
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65 /* ulCriticalNesting will get set to zero when the first task starts. It
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66 cannot be initialised to 0 as this will cause interrupts to be enabled
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67 during the kernel initialisation process. */
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68 unsigned portLONG ulCriticalNesting = ( unsigned portLONG ) 9999;
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70 /* Tick interrupt routines for cooperative and preemptive operation
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71 respectively. The preemptive version is not defined as __irq as it is called
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72 from an asm wrapper function. */
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73 __arm __irq void vPortNonPreemptiveTick( void );
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74 void WDG_IRQHandler( void );
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76 /* VIC interrupt default handler. */
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77 static void prvDefaultHandler( void );
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79 /*-----------------------------------------------------------*/
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82 * Initialise the stack of a task to look exactly as if a call to
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83 * portSAVE_CONTEXT had been called.
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85 * See header file for description.
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87 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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89 portSTACK_TYPE *pxOriginalTOS;
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91 pxOriginalTOS = pxTopOfStack;
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93 /* Setup the initial stack of the task. The stack is set exactly as
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94 expected by the portRESTORE_CONTEXT() macro. */
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96 /* First on the stack is the return address - which in this case is the
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97 start of the task. The offset is added to make the return address appear
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98 as it would within an IRQ ISR. */
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99 *pxTopOfStack = ( portSTACK_TYPE ) pxCode + portINSTRUCTION_SIZE;
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102 *pxTopOfStack = ( portSTACK_TYPE ) 0xaaaaaaaa; /* R14 */
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104 *pxTopOfStack = ( portSTACK_TYPE ) pxOriginalTOS; /* Stack used when task starts goes in R13. */
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106 *pxTopOfStack = ( portSTACK_TYPE ) 0x12121212; /* R12 */
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108 *pxTopOfStack = ( portSTACK_TYPE ) 0x11111111; /* R11 */
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110 *pxTopOfStack = ( portSTACK_TYPE ) 0x10101010; /* R10 */
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112 *pxTopOfStack = ( portSTACK_TYPE ) 0x09090909; /* R9 */
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114 *pxTopOfStack = ( portSTACK_TYPE ) 0x08080808; /* R8 */
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116 *pxTopOfStack = ( portSTACK_TYPE ) 0x07070707; /* R7 */
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118 *pxTopOfStack = ( portSTACK_TYPE ) 0x06060606; /* R6 */
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120 *pxTopOfStack = ( portSTACK_TYPE ) 0x05050505; /* R5 */
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122 *pxTopOfStack = ( portSTACK_TYPE ) 0x04040404; /* R4 */
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124 *pxTopOfStack = ( portSTACK_TYPE ) 0x03030303; /* R3 */
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126 *pxTopOfStack = ( portSTACK_TYPE ) 0x02020202; /* R2 */
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128 *pxTopOfStack = ( portSTACK_TYPE ) 0x01010101; /* R1 */
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131 /* When the task starts is will expect to find the function parameter in
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133 *pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */
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136 /* The status register is set for system mode, with interrupts enabled. */
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137 *pxTopOfStack = ( portSTACK_TYPE ) portINITIAL_SPSR;
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140 /* Interrupt flags cannot always be stored on the stack and will
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141 instead be stored in a variable, which is then saved as part of the
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143 *pxTopOfStack = portNO_CRITICAL_NESTING;
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145 return pxTopOfStack;
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147 /*-----------------------------------------------------------*/
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149 portBASE_TYPE xPortStartScheduler( void )
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151 extern void vPortStartFirstTask( void );
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153 /* Start the timer that generates the tick ISR. Interrupts are disabled
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155 prvSetupTimerInterrupt();
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157 /* Start the first task. */
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158 vPortStartFirstTask();
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160 /* Should not get here! */
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163 /*-----------------------------------------------------------*/
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165 void vPortEndScheduler( void )
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167 /* It is unlikely that the ARM port will require this function as there
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168 is nothing to return to. */
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170 /*-----------------------------------------------------------*/
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172 /* This function is called from an asm wrapper, so does not require the __irq
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174 void WDG_IRQHandler( void )
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176 /* Increment the tick counter. */
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177 vTaskIncrementTick();
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179 #if configUSE_PREEMPTION == 1
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180 /* The new tick value might unblock a task. Ensure the highest task that
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181 is ready to execute is the task that will execute when the tick ISR
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183 vTaskSwitchContext();
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186 /* Clear the interrupt in the watchdog. */
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187 WDG->SR &= ~0x0001;
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189 /*-----------------------------------------------------------*/
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192 #define abs(x) ((x)>0 ? (x) : -(x))
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195 static void prvFindFactors(u32 n, u16 *a, u32 *b)
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197 /* This function is copied from the ST STR7 library and is
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198 copyright STMicroelectronics. Reproduced with permission. */
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202 long err, err_min=n;
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204 *a = a0 = ((n-1)/65536ul) + 1;
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207 for (; *a <= 256; (*a)++)
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210 err = (long)*a * (long)*b - (long)n;
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211 if (abs(err) > (*a / 2))
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214 err = (long)*a * (long)*b - (long)n;
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216 if (abs(err) < abs(err_min))
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221 if (err == 0) break;
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228 /*-----------------------------------------------------------*/
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230 static void prvSetupTimerInterrupt( void )
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232 WDG_InitTypeDef xWdg;
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233 unsigned portSHORT a;
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234 unsigned portLONG n = configCPU_PERIPH_HZ / configTICK_RATE_HZ, b;
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236 /* Configure the watchdog as a free running timer that generates a
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237 periodic interrupt. */
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239 SCU_APBPeriphClockConfig( __WDG, ENABLE );
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241 WDG_StructInit(&xWdg);
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242 prvFindFactors( n, &a, &b );
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243 xWdg.WDG_Prescaler = a - 1;
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244 xWdg.WDG_Preload = b - 1;
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246 WDG_ITConfig(ENABLE);
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248 /* Configure the VIC for the WDG interrupt. */
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249 VIC_Config( WDG_ITLine, VIC_IRQ, 10 );
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250 VIC_ITCmd( WDG_ITLine, ENABLE );
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252 /* Install the default handlers for both VIC's. */
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253 VIC0->DVAR = ( unsigned portLONG ) prvDefaultHandler;
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254 VIC1->DVAR = ( unsigned portLONG ) prvDefaultHandler;
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259 /*-----------------------------------------------------------*/
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261 __arm __interwork void vPortEnterCritical( void )
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263 /* Disable interrupts first! */
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264 portDISABLE_INTERRUPTS();
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266 /* Now interrupts are disabled ulCriticalNesting can be accessed
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267 directly. Increment ulCriticalNesting to keep a count of how many times
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268 portENTER_CRITICAL() has been called. */
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269 ulCriticalNesting++;
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271 /*-----------------------------------------------------------*/
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273 __arm __interwork void vPortExitCritical( void )
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275 if( ulCriticalNesting > portNO_CRITICAL_NESTING )
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277 /* Decrement the nesting count as we are leaving a critical section. */
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278 ulCriticalNesting--;
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280 /* If the nesting level has reached zero then interrupts should be
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282 if( ulCriticalNesting == portNO_CRITICAL_NESTING )
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284 portENABLE_INTERRUPTS();
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288 /*-----------------------------------------------------------*/
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290 static void prvDefaultHandler( void )
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