btimer.c File Reference

#include <rtems.h>
#include <rtems/btimer.h>
#include <bsp.h>

Macros
#define	TICK_INTERVAL   10000UL /* T1's countdown constant (10 ms) */
#define	TIMER_INT_LEVEL   6 /* T1's interrupt level */
#define	TIMER_VECTOR   (VBR0 * 0x10 + 0x8) /* T1 is vector $X8 (p. 2-71)*/
#define	AVG_OVERHEAD   3UL /* It typically takes 3.0 microseconds */
#define	LEAST_VALID   3UL /* Don't trust a value lower than this */

Functions
rtems_isr	timerisr (rtems_vector_number)
void	benchmark_timer_initialize (void)
	Initialize the Benchmark Timer.
benchmark_timer_t	benchmark_timer_read (void)
	Read the Benchmark Timer.
void	benchmark_timer_disable_subtracting_average_overhead (bool find_flag)
	Disable Average Overhead Removal from the Benchmark Timer.

Variables
uint32_t	Ttimer_val
bool	benchmark_timer_find_average_overhead

Detailed Description

This file manages the benchmark timer used by the RTEMS Timing Test Suite. Each measured time period is demarcated by calls to benchmark_timer_initialize() and benchmark_timer_read(). benchmark_timer_read() usually returns the number of microseconds since benchmark_timer_initialize() exitted.

These functions are prototyped in rtems/btimer.h and must be implemented as part of the BSP.

This port does not allow the application to select which timer on the MVME167 to use for the timer, nor does it allow the application to configure the timer. The timer uses the VMEchip2 Tick Timer #1. This timer is distinct from the clock, which uses Tick Timer #2 in the VMEchip2.

All page references are to the MVME166/MVME167/MVME187 Single Board Computer Programmer's Reference Guide (MVME187PG/D2) with the April 1993 supplements/addenda (MVME187PG/D2A1).

Function Documentation

benchmark_timer_disable_subtracting_average_overhead()

void benchmark_timer_disable_subtracting_average_overhead

(

bool

find_flag

)

Disable Average Overhead Removal from the Benchmark Timer.

This method places the benchmark timer in a "raw" mode where it returns the actual number of units which have passed between calls to benchmark_timer_initialize and benchmark_timer_read counting.

Parameters

[in]

find_flag

indicates to enable or disable the mode

benchmark_timer_initialize()

void benchmark_timer_initialize

(

void

)

Initialize the Benchmark Timer.

This method initializes the benchmark timer and resets it to begin counting.

benchmark_timer_read()

benchmark_timer_t benchmark_timer_read

(

void

)

Read the Benchmark Timer.

This method stops the benchmark timer and returns the number of units that have passed since benchmark_timer_initialize was invoked.

Returns

This method returns the number of units with the average overhead removed. If the value is below the minimum trusted value, zero is returned.