2 FreeRTOS V9.0.0rc2 - Copyright (C) 2016 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 This file is part of the FreeRTOS distribution.
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9 FreeRTOS is free software; you can redistribute it and/or modify it under
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10 the terms of the GNU General Public License (version 2) as published by the
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11 Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.
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13 ***************************************************************************
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14 >>! NOTE: The modification to the GPL is included to allow you to !<<
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15 >>! distribute a combined work that includes FreeRTOS without being !<<
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16 >>! obliged to provide the source code for proprietary components !<<
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17 >>! outside of the FreeRTOS kernel. !<<
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18 ***************************************************************************
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20 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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21 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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22 FOR A PARTICULAR PURPOSE. Full license text is available on the following
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23 link: http://www.freertos.org/a00114.html
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25 ***************************************************************************
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27 * FreeRTOS provides completely free yet professionally developed, *
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28 * robust, strictly quality controlled, supported, and cross *
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29 * platform software that is more than just the market leader, it *
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30 * is the industry's de facto standard. *
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32 * Help yourself get started quickly while simultaneously helping *
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33 * to support the FreeRTOS project by purchasing a FreeRTOS *
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34 * tutorial book, reference manual, or both: *
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35 * http://www.FreeRTOS.org/Documentation *
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37 ***************************************************************************
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39 http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
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40 the FAQ page "My application does not run, what could be wrong?". Have you
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41 defined configASSERT()?
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43 http://www.FreeRTOS.org/support - In return for receiving this top quality
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44 embedded software for free we request you assist our global community by
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45 participating in the support forum.
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47 http://www.FreeRTOS.org/training - Investing in training allows your team to
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48 be as productive as possible as early as possible. Now you can receive
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49 FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
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50 Ltd, and the world's leading authority on the world's leading RTOS.
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52 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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53 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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54 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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56 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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57 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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59 http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
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60 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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61 licenses offer ticketed support, indemnification and commercial middleware.
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63 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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64 engineered and independently SIL3 certified version for use in safety and
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65 mission critical applications that require provable dependability.
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73 + Call to taskYIELD() from within tick ISR has been replaced by the more
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74 efficient portSWITCH_CONTEXT().
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75 + ISR function definitions renamed to include the prv prefix.
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79 + Replaced the sUsingPreemption variable with the configUSE_PREEMPTION
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80 macro to be consistent with the later ports.
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83 /*-----------------------------------------------------------
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84 * Implementation of functions defined in portable.h for the Flashlite 186
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86 *----------------------------------------------------------*/
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92 #include "FreeRTOS.h"
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94 #include "portasm.h"
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96 /*lint -e950 Non ANSI reserved words okay in this file only. */
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98 #define portTIMER_EOI_TYPE ( 8 )
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99 #define portRESET_PIC() portOUTPUT_WORD( ( uint16_t ) 0xff22, portTIMER_EOI_TYPE )
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100 #define portTIMER_INT_NUMBER 0x12
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102 #define portTIMER_1_CONTROL_REGISTER ( ( uint16_t ) 0xff5e )
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103 #define portTIMER_0_CONTROL_REGISTER ( ( uint16_t ) 0xff56 )
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104 #define portTIMER_INTERRUPT_ENABLE ( ( uint16_t ) 0x2000 )
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106 /* Setup the hardware to generate the required tick frequency. */
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107 static void prvSetTickFrequency( uint32_t ulTickRateHz );
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109 /* Set the hardware back to the state as per before the scheduler started. */
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110 static void prvExitFunction( void );
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112 /* The ISR used depends on whether the preemptive or cooperative scheduler
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114 #if( configUSE_PREEMPTION == 1 )
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115 /* Tick service routine used by the scheduler when preemptive scheduling is
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117 static void __interrupt __far prvPreemptiveTick( void );
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119 /* Tick service routine used by the scheduler when cooperative scheduling is
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121 static void __interrupt __far prvNonPreemptiveTick( void );
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124 /* Trap routine used by taskYIELD() to manually cause a context switch. */
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125 static void __interrupt __far prvYieldProcessor( void );
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127 /*lint -e956 File scopes necessary here. */
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129 /* Set true when the vectors are set so the scheduler will service the tick. */
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130 static BaseType_t xSchedulerRunning = pdFALSE;
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132 /* Points to the original routine installed on the vector we use for manual
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133 context switches. This is then used to restore the original routine during
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134 prvExitFunction(). */
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135 static void ( __interrupt __far *pxOldSwitchISR )();
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137 /* Used to restore the original DOS context when the scheduler is ended. */
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138 static jmp_buf xJumpBuf;
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142 /*-----------------------------------------------------------*/
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143 BaseType_t xPortStartScheduler( void )
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145 /* This is called with interrupts already disabled. */
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147 /* Remember what was on the interrupts we are going to use
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148 so we can put them back later if required. */
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149 pxOldSwitchISR = _dos_getvect( portSWITCH_INT_NUMBER );
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151 /* Put our manual switch (yield) function on a known
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153 _dos_setvect( portSWITCH_INT_NUMBER, prvYieldProcessor );
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155 #if( configUSE_PREEMPTION == 1 )
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157 /* Put our tick switch function on the timer interrupt. */
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158 _dos_setvect( portTIMER_INT_NUMBER, prvPreemptiveTick );
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162 /* We want the timer interrupt to just increment the tick count. */
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163 _dos_setvect( portTIMER_INT_NUMBER, prvNonPreemptiveTick );
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167 prvSetTickFrequency( configTICK_RATE_HZ );
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169 /* Clean up function if we want to return to DOS. */
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170 if( setjmp( xJumpBuf ) != 0 )
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173 xSchedulerRunning = pdFALSE;
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177 xSchedulerRunning = pdTRUE;
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179 /* Kick off the scheduler by setting up the context of the first task. */
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180 portFIRST_CONTEXT();
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183 return xSchedulerRunning;
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185 /*-----------------------------------------------------------*/
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187 /* The ISR used depends on whether the preemptive or cooperative scheduler
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189 #if( configUSE_PREEMPTION == 1 )
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190 static void __interrupt __far prvPreemptiveTick( void )
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192 /* Get the scheduler to update the task states following the tick. */
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193 if( xTaskIncrementTick() != pdFALSE )
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195 /* Switch in the context of the next task to be run. */
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196 portSWITCH_CONTEXT();
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199 /* Reset the PIC ready for the next time. */
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203 static void __interrupt __far prvNonPreemptiveTick( void )
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205 /* Same as preemptive tick, but the cooperative scheduler is being used
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206 so we don't have to switch in the context of the next task. */
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207 xTaskIncrementTick();
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211 /*-----------------------------------------------------------*/
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213 static void __interrupt __far prvYieldProcessor( void )
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215 /* Switch in the context of the next task to be run. */
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216 portSWITCH_CONTEXT();
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218 /*-----------------------------------------------------------*/
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220 void vPortEndScheduler( void )
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222 /* Jump back to the processor state prior to starting the
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223 scheduler. This means we are not going to be using a
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224 task stack frame so the task can be deleted. */
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225 longjmp( xJumpBuf, 1 );
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227 /*-----------------------------------------------------------*/
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229 static void prvExitFunction( void )
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231 const uint16_t usTimerDisable = 0x0000;
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232 uint16_t usTimer0Control;
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234 /* Interrupts should be disabled here anyway - but no
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235 harm in making sure. */
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236 portDISABLE_INTERRUPTS();
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237 if( xSchedulerRunning == pdTRUE )
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239 /* Put back the switch interrupt routines that was in place
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240 before the scheduler started. */
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241 _dos_setvect( portSWITCH_INT_NUMBER, pxOldSwitchISR );
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244 /* Disable the timer used for the tick to ensure the scheduler is
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245 not called before restoring interrupts. There was previously nothing
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246 on this timer so there is no old ISR to restore. */
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247 portOUTPUT_WORD( portTIMER_1_CONTROL_REGISTER, usTimerDisable );
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249 /* Restart the DOS tick. */
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250 usTimer0Control = portINPUT_WORD( portTIMER_0_CONTROL_REGISTER );
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251 usTimer0Control |= portTIMER_INTERRUPT_ENABLE;
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252 portOUTPUT_WORD( portTIMER_0_CONTROL_REGISTER, usTimer0Control );
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255 portENABLE_INTERRUPTS();
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257 /*-----------------------------------------------------------*/
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259 static void prvSetTickFrequency( uint32_t ulTickRateHz )
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261 const uint16_t usMaxCountRegister = 0xff5a;
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262 const uint16_t usTimerPriorityRegister = 0xff32;
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263 const uint16_t usTimerEnable = 0xC000;
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264 const uint16_t usRetrigger = 0x0001;
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265 const uint16_t usTimerHighPriority = 0x0000;
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266 uint16_t usTimer0Control;
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268 /* ( CPU frequency / 4 ) / clock 2 max count [inpw( 0xff62 ) = 7] */
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270 const uint32_t ulClockFrequency = ( uint32_t ) 0x7f31a0UL;
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272 uint32_t ulTimerCount = ulClockFrequency / ulTickRateHz;
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274 portOUTPUT_WORD( portTIMER_1_CONTROL_REGISTER, usTimerEnable | portTIMER_INTERRUPT_ENABLE | usRetrigger );
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275 portOUTPUT_WORD( usMaxCountRegister, ( uint16_t ) ulTimerCount );
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276 portOUTPUT_WORD( usTimerPriorityRegister, usTimerHighPriority );
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278 /* Stop the DOS tick - don't do this if you want to maintain a TOD clock. */
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279 usTimer0Control = portINPUT_WORD( portTIMER_0_CONTROL_REGISTER );
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280 usTimer0Control &= ~portTIMER_INTERRUPT_ENABLE;
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281 portOUTPUT_WORD( portTIMER_0_CONTROL_REGISTER, usTimer0Control );
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