[cb585c3] | 1 | /* timer.c |
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| 2 | * |
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| 3 | * This file implements a benchmark timer using the General Purpose Timer on |
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| 4 | * the MEC. |
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| 5 | * |
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[08311cc3] | 6 | * COPYRIGHT (c) 1989-1999. |
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[cb585c3] | 7 | * On-Line Applications Research Corporation (OAR). |
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| 8 | * |
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[98e4ebf5] | 9 | * The license and distribution terms for this file may be |
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| 10 | * found in the file LICENSE in this distribution or at |
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[7d2a0641] | 11 | * http://www.rtems.com/license/LICENSE. |
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[cb585c3] | 12 | * |
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| 13 | * Ported to ERC32 implementation of the SPARC by On-Line Applications |
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[6128a4a] | 14 | * Research Corporation (OAR) under contract to the European Space |
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[cb585c3] | 15 | * Agency (ESA). |
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| 16 | * |
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[6128a4a] | 17 | * ERC32 modifications of respective RTEMS file: COPYRIGHT (c) 1995. |
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[cb585c3] | 18 | * European Space Agency. |
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| 19 | * |
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| 20 | * $Id$ |
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| 21 | */ |
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| 22 | |
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| 23 | #include <bsp.h> |
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| 24 | |
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[e511e126] | 25 | rtems_boolean benchmark_timer_find_average_overhead; |
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[cb585c3] | 26 | |
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[e511e126] | 27 | rtems_boolean benchmark_timer_is_initialized = FALSE; |
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[cb585c3] | 28 | |
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[e511e126] | 29 | void benchmark_timer_initialize(void) |
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[cb585c3] | 30 | { |
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| 31 | /* |
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| 32 | * Timer runs long and accurate enough not to require an interrupt. |
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| 33 | */ |
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| 34 | |
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[e511e126] | 35 | if ( benchmark_timer_is_initialized == FALSE ) { |
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[cb585c3] | 36 | |
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| 37 | /* approximately 1 us per countdown */ |
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| 38 | ERC32_MEC.General_Purpose_Timer_Scalar = CLOCK_SPEED - 1; |
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| 39 | ERC32_MEC.General_Purpose_Timer_Counter = 0xffffffff; |
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| 40 | |
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| 41 | } else { |
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[e511e126] | 42 | benchmark_timer_is_initialized = TRUE; |
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[cb585c3] | 43 | } |
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| 44 | |
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[6128a4a] | 45 | ERC32_MEC_Set_General_Purpose_Timer_Control( |
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| 46 | ERC32_MEC_TIMER_COUNTER_ENABLE_COUNTING | |
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[cb585c3] | 47 | ERC32_MEC_TIMER_COUNTER_LOAD_COUNTER |
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| 48 | ); |
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| 49 | |
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[6128a4a] | 50 | ERC32_MEC_Set_General_Purpose_Timer_Control( |
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[cb585c3] | 51 | ERC32_MEC_TIMER_COUNTER_ENABLE_COUNTING |
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| 52 | ); |
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| 53 | |
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| 54 | } |
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| 55 | |
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[3ca2768] | 56 | #if ENABLE_SIS_QUIRKS |
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| 57 | #define AVG_OVERHEAD 8 /* It typically takes 3.0 microseconds */ |
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[cb585c3] | 58 | /* to start/stop the timer. */ |
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[3ca2768] | 59 | #define LEAST_VALID 9 /* Don't trust a value lower than this */ |
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| 60 | #else |
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| 61 | #define AVG_OVERHEAD 12 /* It typically takes 3.0 microseconds */ |
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| 62 | /* to start/stop the timer. */ |
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| 63 | #define LEAST_VALID 13 /* Don't trust a value lower than this */ |
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| 64 | #endif |
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[cb585c3] | 65 | |
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[e511e126] | 66 | int benchmark_timer_read(void) |
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[cb585c3] | 67 | { |
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[1be1e913] | 68 | uint32_t total; |
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[cb585c3] | 69 | |
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| 70 | total = ERC32_MEC.General_Purpose_Timer_Counter; |
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| 71 | |
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| 72 | total = 0xffffffff - total; |
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| 73 | |
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[e511e126] | 74 | if ( benchmark_timer_find_average_overhead == 1 ) |
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[cb585c3] | 75 | return total; /* in one microsecond units */ |
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| 76 | |
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| 77 | if ( total < LEAST_VALID ) |
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| 78 | return 0; /* below timer resolution */ |
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| 79 | |
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| 80 | return total - AVG_OVERHEAD; |
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| 81 | } |
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| 82 | |
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[e511e126] | 83 | void benchmark_timer_disable_subtracting_average_overhead( |
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[cb585c3] | 84 | rtems_boolean find_flag |
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| 85 | ) |
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| 86 | { |
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[e511e126] | 87 | benchmark_timer_find_average_overhead = find_flag; |
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[cb585c3] | 88 | } |
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