[7150f00f] | 1 | /*-------------------------------------------------------------------------+ |
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| 2 | | timer.c v1.1 - PC386 BSP - 1997/08/07 |
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| 3 | +--------------------------------------------------------------------------+ |
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| 4 | | This file contains the PC386 timer package. |
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| 5 | +--------------------------------------------------------------------------+ |
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| 6 | | NOTE: It is important that the timer start/stop overhead be determined |
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| 7 | | when porting or modifying this code. |
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| 8 | +--------------------------------------------------------------------------+ |
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| 9 | | (C) Copyright 1997 - |
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| 10 | | - NavIST Group - Real-Time Distributed Systems and Industrial Automation |
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| 11 | | |
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| 12 | | http://pandora.ist.utl.pt |
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| 13 | | |
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| 14 | | Instituto Superior Tecnico * Lisboa * PORTUGAL |
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| 15 | +--------------------------------------------------------------------------+ |
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| 16 | | Disclaimer: |
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| 17 | | |
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| 18 | | This file is provided "AS IS" without warranty of any kind, either |
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| 19 | | expressed or implied. |
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| 20 | +--------------------------------------------------------------------------+ |
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| 21 | | This code is base on: |
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| 22 | | timer.c,v 1.7 1995/12/19 20:07:43 joel Exp - go32 BSP |
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| 23 | | With the following copyright notice: |
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| 24 | | ************************************************************************** |
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| 25 | | * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994. * |
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| 26 | | * On-Line Applications Research Corporation (OAR). * |
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| 27 | | * All rights assigned to U.S. Government, 1994. * |
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| 28 | | * * |
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| 29 | | * This material may be reproduced by or for the U.S. Government pursuant * |
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| 30 | | * to the copyright license under the clause at DFARS 252.227-7013. This * |
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| 31 | | * notice must appear in all copies of this file and its derivatives. * |
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| 32 | | ************************************************************************** |
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| 33 | +--------------------------------------------------------------------------*/ |
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| 34 | |
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| 35 | |
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| 36 | #include <stdlib.h> |
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| 37 | |
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| 38 | #include <bsp.h> |
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| 39 | #include <irq.h> |
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| 40 | |
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| 41 | /*-------------------------------------------------------------------------+ |
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| 42 | | Constants |
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| 43 | +--------------------------------------------------------------------------*/ |
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| 44 | #define TIMER_IRQ 0x00 /* Timer IRQ. */ |
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| 45 | #define AVG_OVERHEAD 0 /* 0.1 microseconds to start/stop timer. */ |
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| 46 | #define LEAST_VALID 1 /* Don't trust a value lower than this. */ |
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| 47 | |
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| 48 | /*-------------------------------------------------------------------------+ |
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| 49 | | Global Variables |
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| 50 | +--------------------------------------------------------------------------*/ |
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| 51 | volatile rtems_unsigned32 Ttimer_val; |
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| 52 | rtems_boolean Timer_driver_Find_average_overhead = TRUE; |
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| 53 | |
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| 54 | /*-------------------------------------------------------------------------+ |
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| 55 | | Pentium optimized timer handling. |
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| 56 | +--------------------------------------------------------------------------*/ |
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| 57 | #if defined(pentium) |
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| 58 | |
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| 59 | /*-------------------------------------------------------------------------+ |
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| 60 | | Function: rdtsc |
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| 61 | | Description: Read the value of PENTIUM on-chip cycle counter. |
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| 62 | | Global Variables: None. |
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| 63 | | Arguments: None. |
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| 64 | | Returns: Value of PENTIUM on-chip cycle counter. |
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| 65 | +--------------------------------------------------------------------------*/ |
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| 66 | static inline unsigned long long |
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| 67 | rdtsc(void) |
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| 68 | { |
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| 69 | /* Return the value of the on-chip cycle counter. */ |
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| 70 | unsigned long long result; |
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| 71 | asm volatile(".byte 0x0F, 0x31" : "=A" (result)); |
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| 72 | return result; |
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| 73 | } /* rdtsc */ |
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| 74 | |
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| 75 | |
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| 76 | /*-------------------------------------------------------------------------+ |
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| 77 | | Function: Timer_exit |
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| 78 | | Description: Timer cleanup routine at RTEMS exit. NOTE: This routine is |
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| 79 | | not really necessary, since there will be a reset at exit. |
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| 80 | | Global Variables: None. |
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| 81 | | Arguments: None. |
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| 82 | | Returns: Nothing. |
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| 83 | +--------------------------------------------------------------------------*/ |
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| 84 | void |
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| 85 | Timer_exit(void) |
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| 86 | { |
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| 87 | PC386_disableIrq(TIMER_IRQ); |
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| 88 | } /* Timer_exit */ |
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| 89 | |
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| 90 | |
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| 91 | /*-------------------------------------------------------------------------+ |
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| 92 | | Function: Timer_initialize |
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| 93 | | Description: Timer initialization routine. |
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| 94 | | Global Variables: Ttimer_val. |
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| 95 | | Arguments: None. |
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| 96 | | Returns: Nothing. |
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| 97 | +--------------------------------------------------------------------------*/ |
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| 98 | void |
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| 99 | Timer_initialize(void) |
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| 100 | { |
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| 101 | static rtems_boolean First = TRUE; |
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| 102 | |
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| 103 | if (First) |
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| 104 | { |
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| 105 | First = FALSE; |
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| 106 | |
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| 107 | atexit(Timer_exit); /* Try not to hose the system at exit. */ |
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| 108 | PC386_enableIrq(TIMER_IRQ); |
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| 109 | /* Disable the programmable timer so ticks don't interfere. */ |
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| 110 | } |
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| 111 | Ttimer_val = rdtsc(); /* read starting time */ |
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| 112 | } /* Timer_initialize */ |
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| 113 | |
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| 114 | |
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| 115 | /*-------------------------------------------------------------------------+ |
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| 116 | | Function: Read_timer |
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| 117 | | Description: Read hardware timer value. |
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| 118 | | Global Variables: Ttimer_val, Timer_driver_Find_average_overhead. |
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| 119 | | Arguments: None. |
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| 120 | | Returns: Nothing. |
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| 121 | +--------------------------------------------------------------------------*/ |
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| 122 | rtems_unsigned32 |
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| 123 | Read_timer(void) |
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| 124 | { |
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| 125 | register rtems_unsigned32 total; |
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| 126 | |
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| 127 | total = (rtems_unsigned32)(rdtsc() - Ttimer_val); |
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| 128 | |
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| 129 | if (Timer_driver_Find_average_overhead) |
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| 130 | return total; |
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| 131 | else if (total < LEAST_VALID) |
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| 132 | return 0; /* below timer resolution */ |
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| 133 | else |
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| 134 | return (total - AVG_OVERHEAD); |
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| 135 | } /* Read_timer */ |
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| 136 | |
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| 137 | #else /* pentium */ |
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| 138 | |
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| 139 | /*-------------------------------------------------------------------------+ |
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| 140 | | Non-Pentium timer handling. |
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| 141 | +--------------------------------------------------------------------------*/ |
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| 142 | #define US_PER_ISR 250 /* Number of micro-seconds per timer interruption */ |
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| 143 | |
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| 144 | /*-------------------------------------------------------------------------+ |
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| 145 | | External Prototypes |
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| 146 | +--------------------------------------------------------------------------*/ |
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| 147 | extern rtems_isr timerisr(rtems_vector_number); |
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| 148 | /* timer (int 08h) Interrupt Service Routine (defined in 'timerisr.s') */ |
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| 149 | |
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| 150 | /*-------------------------------------------------------------------------+ |
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| 151 | | Function: Timer_exit |
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| 152 | | Description: Timer cleanup routine at RTEMS exit. NOTE: This routine is |
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| 153 | | not really necessary, since there will be a reset at exit. |
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| 154 | | Global Variables: None. |
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| 155 | | Arguments: None. |
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| 156 | | Returns: Nothing. |
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| 157 | +--------------------------------------------------------------------------*/ |
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| 158 | void |
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| 159 | Timer_exit(void) |
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| 160 | { |
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| 161 | /* reset timer mode to standard (DOS) value */ |
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| 162 | outport_byte(TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN); |
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| 163 | outport_byte(TIMER_CNTR0, 0); |
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| 164 | outport_byte(TIMER_CNTR0, 0); |
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| 165 | } /* Timer_exit */ |
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| 166 | |
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| 167 | |
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| 168 | /*-------------------------------------------------------------------------+ |
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| 169 | | Function: Timer_initialize |
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| 170 | | Description: Timer initialization routine. |
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| 171 | | Global Variables: Ttimer_val. |
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| 172 | | Arguments: None. |
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| 173 | | Returns: Nothing. |
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| 174 | +--------------------------------------------------------------------------*/ |
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| 175 | void |
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| 176 | Timer_initialize(void) |
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| 177 | { |
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| 178 | static rtems_boolean First = TRUE; |
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| 179 | |
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| 180 | if (First) |
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| 181 | { |
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| 182 | First = FALSE; |
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| 183 | |
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| 184 | atexit(Timer_exit); /* Try not to hose the system at exit. */ |
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| 185 | |
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| 186 | /* install a raw interrupt handler for timer */ |
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| 187 | PC386_installRawIrqHandler(TIMER_IRQ, timerisr); |
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| 188 | |
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| 189 | /* load timer for US_PER_ISR microsecond period */ |
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| 190 | outport_byte(TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN); |
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| 191 | outport_byte(TIMER_CNTR0, US_TO_TICK(US_PER_ISR) >> 0 & 0xff); |
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| 192 | outport_byte(TIMER_CNTR0, US_TO_TICK(US_PER_ISR) >> 8 & 0xff); |
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| 193 | } |
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| 194 | /* wait for ISR to be called at least once */ |
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| 195 | Ttimer_val = 0; |
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| 196 | while (Ttimer_val == 0) |
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| 197 | continue; |
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| 198 | Ttimer_val = 0; |
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| 199 | } /* Timer_initialize */ |
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| 200 | |
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| 201 | |
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| 202 | /*-------------------------------------------------------------------------+ |
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| 203 | | Function: Read_timer |
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| 204 | | Description: Read hardware timer value. |
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| 205 | | Global Variables: Ttimer_val, Timer_driver_Find_average_overhead. |
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| 206 | | Arguments: None. |
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| 207 | | Returns: Nothing. |
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| 208 | +--------------------------------------------------------------------------*/ |
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| 209 | rtems_unsigned32 |
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| 210 | Read_timer(void) |
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| 211 | { |
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| 212 | register rtems_unsigned32 total, clicks; |
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| 213 | register rtems_unsigned8 lsb, msb; |
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| 214 | |
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| 215 | outport_byte(TIMER_MODE, TIMER_SEL0|TIMER_LATCH); |
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| 216 | inport_byte(TIMER_CNTR0, lsb); |
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| 217 | inport_byte(TIMER_CNTR0, msb); |
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| 218 | clicks = (msb << 8) | lsb; |
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| 219 | total = (Ttimer_val * US_PER_ISR) + (US_PER_ISR - TICK_TO_US(clicks)); |
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| 220 | |
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| 221 | if (Timer_driver_Find_average_overhead) |
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| 222 | return total; |
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| 223 | else if (total < LEAST_VALID) |
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| 224 | return 0; /* below timer resolution */ |
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| 225 | else |
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| 226 | return (total - AVG_OVERHEAD); |
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| 227 | } |
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| 228 | |
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| 229 | #endif /* pentium */ |
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| 230 | |
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| 231 | |
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| 232 | /*-------------------------------------------------------------------------+ |
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| 233 | | Function: Empty_function |
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| 234 | | Description: Empty function used in time tests. |
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| 235 | | Global Variables: None. |
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| 236 | | Arguments: None. |
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| 237 | | Returns: Nothing. |
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| 238 | +--------------------------------------------------------------------------*/ |
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| 239 | rtems_status_code Empty_function(void) |
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| 240 | { |
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| 241 | return RTEMS_SUCCESSFUL; |
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| 242 | } /* Empty function */ |
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| 243 | |
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| 244 | |
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| 245 | /*-------------------------------------------------------------------------+ |
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| 246 | | Function: Set_find_average_overhead |
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| 247 | | Description: Set internal Timer_driver_Find_average_overhead flag value. |
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| 248 | | Global Variables: Timer_driver_Find_average_overhead. |
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| 249 | | Arguments: find_flag - new value of the flag. |
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| 250 | | Returns: Nothing. |
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| 251 | +--------------------------------------------------------------------------*/ |
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| 252 | void |
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| 253 | Set_find_average_overhead(rtems_boolean find_flag) |
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| 254 | { |
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| 255 | Timer_driver_Find_average_overhead = find_flag; |
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| 256 | } /* Set_find_average_overhead */ |
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