[637df35] | 1 | /* Clock_initialize |
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| 2 | * |
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| 3 | * This routine initializes the 8254 timer under GO32. |
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| 4 | * The tick frequency is 1 millisecond. |
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| 5 | * |
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| 6 | * Input parameters: NONE |
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| 7 | * |
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| 8 | * Output parameters: NONE |
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| 9 | * |
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| 10 | * $Id$ |
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| 11 | */ |
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| 12 | |
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| 13 | #include <bsp.h> |
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[3a4ae6c] | 14 | #include <rtems/libio.h> |
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| 15 | |
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[637df35] | 16 | #include <stdlib.h> |
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| 17 | |
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| 18 | volatile rtems_unsigned32 Clock_driver_ticks; |
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[3a4ae6c] | 19 | rtems_unsigned32 Clock_isrs_per_tick; /* ISRs per tick */ |
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| 20 | rtems_unsigned32 Clock_isrs; /* ISRs until next tick */ |
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[637df35] | 21 | rtems_isr_entry Old_ticker; |
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| 22 | |
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[3a4ae6c] | 23 | #define CLOCK_VECTOR 0x8 |
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[637df35] | 24 | |
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[3a4ae6c] | 25 | void Clock_exit( void ); |
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| 26 | |
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| 27 | /* |
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| 28 | * These are set by clock driver during its init |
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| 29 | */ |
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| 30 | |
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| 31 | rtems_device_major_number rtems_clock_major = ~0; |
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| 32 | rtems_device_minor_number rtems_clock_minor; |
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| 33 | |
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| 34 | rtems_isr Clock_isr( |
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| 35 | rtems_vector_number vector |
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[637df35] | 36 | ) |
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| 37 | { |
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[3a4ae6c] | 38 | /* touch interrupt controller for irq0 (0x20+0) */ |
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| 39 | outport_byte( 0x20, 0x20 ); |
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[637df35] | 40 | |
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[3a4ae6c] | 41 | Clock_driver_ticks += 1; |
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| 42 | |
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| 43 | #if 0 && defined(pentium) |
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| 44 | { |
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| 45 | extern long long Last_RDTSC; |
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| 46 | __asm __volatile( ".byte 0x0F, 0x31" : "=A" (Last_RDTSC) ); |
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| 47 | } |
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| 48 | #endif |
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| 49 | |
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| 50 | if ( Clock_isrs == 1 ) { |
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| 51 | rtems_clock_tick(); |
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| 52 | Clock_isrs = Clock_isrs_per_tick; |
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| 53 | } else { |
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| 54 | Clock_isrs -= 1; |
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| 55 | } |
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[637df35] | 56 | } |
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| 57 | |
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| 58 | void Install_clock( |
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| 59 | rtems_isr_entry clock_isr |
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| 60 | ) |
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| 61 | { |
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[3a4ae6c] | 62 | unsigned int microseconds_per_isr; |
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[637df35] | 63 | |
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| 64 | #if 0 |
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[3a4ae6c] | 65 | /* Initialize clock from on-board real time clock. This breaks the */ |
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[637df35] | 66 | /* test code which assumes which assumes the application will do it. */ |
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| 67 | { |
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[3a4ae6c] | 68 | rtems_time_of_day Now; |
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| 69 | extern void init_rtc( void ); |
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| 70 | extern long rtc_read( rtems_time_of_day * tod ); |
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| 71 | init_rtc(); |
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| 72 | if ( rtc_read( &Now ) >= 0 ) |
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| 73 | clock_set( &Now ); |
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| 74 | } |
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[637df35] | 75 | #endif |
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| 76 | |
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[3a4ae6c] | 77 | /* Start by assuming hardware counter is large enough, then */ |
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| 78 | /* scale it until it actually fits. */ |
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[637df35] | 79 | Clock_driver_ticks = 0; |
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| 80 | Clock_isrs_per_tick = 1; |
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| 81 | |
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| 82 | if ( BSP_Configuration.microseconds_per_tick == 0 ) |
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[3a4ae6c] | 83 | microseconds_per_isr = 10000; /* default 10 ms */ |
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[637df35] | 84 | else |
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[3a4ae6c] | 85 | microseconds_per_isr = BSP_Configuration.microseconds_per_tick; |
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[637df35] | 86 | while ( US_TO_TICK(microseconds_per_isr) > 65535 ) { |
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[3a4ae6c] | 87 | Clock_isrs_per_tick *= 10; |
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| 88 | microseconds_per_isr /= 10; |
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[637df35] | 89 | } |
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| 90 | |
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| 91 | /* Initialize count in ckisr.c */ |
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| 92 | Clock_isrs = Clock_isrs_per_tick; |
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| 93 | |
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| 94 | #if 0 |
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| 95 | /* This was dropped in the last revision. Its a nice thing to know. */ |
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| 96 | TICKS_PER_SECOND = 1000000 / (Clock_isrs_per_tick * microseconds_per_isr); |
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| 97 | #endif |
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| 98 | |
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| 99 | if ( BSP_Configuration.ticks_per_timeslice ) { |
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[3a4ae6c] | 100 | /* 105/88 approximates TIMER_TICK*1e-6 */ |
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| 101 | unsigned int count = US_TO_TICK( microseconds_per_isr ); |
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[637df35] | 102 | |
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[3a4ae6c] | 103 | Old_ticker = (rtems_isr_entry) set_vector( clock_isr, CLOCK_VECTOR, 1 ); |
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| 104 | outport_byte( TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN ); |
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| 105 | outport_byte( TIMER_CNTR0, count >> 0 & 0xff ); |
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| 106 | outport_byte( TIMER_CNTR0, count >> 8 & 0xff ); |
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[637df35] | 107 | } |
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| 108 | atexit( Clock_exit ); |
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| 109 | } |
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| 110 | |
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[3a4ae6c] | 111 | void ReInstall_clock( |
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| 112 | rtems_isr_entry clock_isr |
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| 113 | ) |
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| 114 | { |
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| 115 | rtems_unsigned32 isrlevel = 0; |
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| 116 | |
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| 117 | rtems_interrupt_disable( isrlevel ); |
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| 118 | (void) set_vector( clock_isr, CLOCK_VECTOR, 1 ); |
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| 119 | rtems_interrupt_enable( isrlevel ); |
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| 120 | } |
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| 121 | |
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[637df35] | 122 | void Clock_exit( void ) |
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| 123 | { |
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| 124 | if ( BSP_Configuration.ticks_per_timeslice ) { |
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[3a4ae6c] | 125 | extern void rtc_set_dos_date( void ); |
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| 126 | |
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| 127 | /* reset to DOS value: */ |
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| 128 | outport_byte( TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN ); |
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| 129 | outport_byte( TIMER_CNTR0, 0 ); |
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| 130 | outport_byte( TIMER_CNTR0, 0 ); |
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| 131 | |
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| 132 | /* reset time-of-day */ |
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| 133 | rtc_set_dos_date(); |
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| 134 | |
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| 135 | /* re-enable old handler: assume it was one of ours */ |
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| 136 | set_vector( (rtems_isr_entry)Old_ticker, CLOCK_VECTOR, 1 ); |
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[637df35] | 137 | } |
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| 138 | } |
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| 139 | |
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[3a4ae6c] | 140 | rtems_device_driver Clock_initialize( |
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| 141 | rtems_device_major_number major, |
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| 142 | rtems_device_minor_number minor, |
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| 143 | void *pargp |
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| 144 | ) |
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| 145 | { |
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| 146 | Install_clock( Clock_isr ); |
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| 147 | |
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| 148 | /* |
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| 149 | * make major/minor avail to others such as shared memory driver |
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| 150 | */ |
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| 151 | |
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| 152 | rtems_clock_major = major; |
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| 153 | rtems_clock_minor = minor; |
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| 154 | |
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| 155 | return RTEMS_SUCCESSFUL; |
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| 156 | } |
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| 157 | |
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| 158 | rtems_device_driver Clock_control( |
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| 159 | rtems_device_major_number major, |
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| 160 | rtems_device_minor_number minor, |
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| 161 | void *pargp |
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| 162 | ) |
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| 163 | { |
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| 164 | rtems_libio_ioctl_args_t *args = pargp; |
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| 165 | |
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| 166 | if (args == 0) |
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| 167 | goto done; |
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| 168 | |
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| 169 | /* |
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| 170 | * This is hokey, but until we get a defined interface |
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| 171 | * to do this, it will just be this simple... |
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| 172 | */ |
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| 173 | |
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| 174 | if (args->command == rtems_build_name('I', 'S', 'R', ' ')) |
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| 175 | { |
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| 176 | Clock_isr(CLOCK_VECTOR); |
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| 177 | } |
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| 178 | else if (args->command == rtems_build_name('N', 'E', 'W', ' ')) |
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| 179 | { |
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| 180 | ReInstall_clock(args->buffer); |
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| 181 | } |
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| 182 | |
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| 183 | done: |
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| 184 | return RTEMS_SUCCESSFUL; |
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| 185 | } |
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[637df35] | 186 | |
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| 187 | #if 0 && defined(pentium) |
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[3a4ae6c] | 188 | /* This can be used to get extremely accurate timing on a pentium. */ |
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| 189 | /* It isn't supported. [bryce] */ |
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[637df35] | 190 | #define HZ 90.0 |
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| 191 | volatile long long Last_RDTSC; |
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| 192 | #define RDTSC()\ |
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| 193 | ({ long long _now; __asm __volatile (".byte 0x0F,0x31":"=A"(_now)); _now; }) |
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[3a4ae6c] | 194 | |
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[637df35] | 195 | long long Kernel_Time_ns( void ) |
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| 196 | { |
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| 197 | extern rtems_unsigned32 _TOD_Ticks_per_second; |
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| 198 | unsigned isrs_per_second = Clock_isrs_per_tick * _TOD_Ticks_per_second; |
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| 199 | long long now; |
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| 200 | int flags; |
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| 201 | disable_intr( flags ); |
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| 202 | now = 1e9 * Clock_driver_ticks / isrs_per_second |
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[3a4ae6c] | 203 | + (RDTSC() - Last_RDTSC) * (1000.0/HZ); |
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[637df35] | 204 | enable_intr( flags ); |
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| 205 | return now; |
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| 206 | } |
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| 207 | #endif |
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