1 | /* |
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2 | * Thread Handler |
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3 | * |
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4 | * |
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5 | * COPYRIGHT (c) 1989-1998. |
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6 | * On-Line Applications Research Corporation (OAR). |
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7 | * Copyright assigned to U.S. Government, 1994. |
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8 | * |
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9 | * The license and distribution terms for this file may be |
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10 | * found in found in the file LICENSE in this distribution or at |
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11 | * http://www.OARcorp.com/rtems/license.html. |
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12 | * |
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13 | * $Id$ |
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14 | */ |
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15 | |
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16 | #include <rtems/system.h> |
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17 | #include <rtems/score/apiext.h> |
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18 | #include <rtems/score/context.h> |
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19 | #include <rtems/score/interr.h> |
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20 | #include <rtems/score/isr.h> |
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21 | #include <rtems/score/object.h> |
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22 | #include <rtems/score/priority.h> |
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23 | #include <rtems/score/states.h> |
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24 | #include <rtems/score/sysstate.h> |
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25 | #include <rtems/score/thread.h> |
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26 | #include <rtems/score/threadq.h> |
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27 | #include <rtems/score/userext.h> |
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28 | #include <rtems/score/wkspace.h> |
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29 | |
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30 | /*PAGE |
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31 | * |
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32 | * _Thread_Start_multitasking |
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33 | * |
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34 | * This kernel routine readies the requested thread, the thread chain |
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35 | * is adjusted. A new heir thread may be selected. |
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36 | * |
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37 | * Input parameters: |
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38 | * system_thread - pointer to system initialization thread control block |
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39 | * idle_thread - pointer to idle thread control block |
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40 | * |
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41 | * Output parameters: NONE |
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42 | * |
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43 | * NOTE: This routine uses the "blocking" heir selection mechanism. |
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44 | * This insures the correct heir after a thread restart. |
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45 | * |
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46 | * INTERRUPT LATENCY: |
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47 | * ready chain |
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48 | * select heir |
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49 | */ |
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50 | |
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51 | void _Thread_Start_multitasking( void ) |
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52 | { |
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53 | /* |
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54 | * The system is now multitasking and completely initialized. |
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55 | * This system thread now either "goes away" in a single processor |
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56 | * system or "turns into" the server thread in an MP system. |
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57 | */ |
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58 | |
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59 | _System_state_Set( SYSTEM_STATE_UP ); |
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60 | |
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61 | _Context_Switch_necessary = FALSE; |
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62 | |
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63 | _Thread_Executing = _Thread_Heir; |
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64 | |
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65 | /* |
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66 | * Get the init task(s) running. |
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67 | * |
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68 | * Note: Thread_Dispatch() is normally used to dispatch threads. As |
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69 | * part of its work, Thread_Dispatch() restores floating point |
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70 | * state for the heir task. |
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71 | * |
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72 | * This code avoids Thread_Dispatch(), and so we have to restore |
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73 | * (actually initialize) the floating point state "by hand". |
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74 | * |
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75 | * Ignore the CPU_USE_DEFERRED_FP_SWITCH because we must always |
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76 | * switch in the first thread if it is FP. |
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77 | */ |
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78 | |
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79 | |
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80 | #if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE ) |
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81 | /* |
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82 | * don't need to worry about saving BSP's floating point state |
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83 | */ |
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84 | |
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85 | if ( _Thread_Heir->fp_context != NULL ) |
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86 | _Context_Restore_fp( &_Thread_Heir->fp_context ); |
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87 | #endif |
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88 | |
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89 | _Context_Switch( &_Thread_BSP_context, &_Thread_Heir->Registers ); |
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90 | } |
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