readme.txt

来自「一个小型化的嵌入式实时操作系统源代码」· 文本 代码 · 共 35 行

looptime is a test program for the uC/OS Board Support Package (BSP).

Execution
Program runs in a loop until 20 timer interrupts have occured or the loop count
reaches a maximum value. Each interrupt stores the current loop count into an
array along with the interrupt count. After interrupt count reaches 20 the
array is printed out through port 2. You should see 20 rows. The first rows
look like:
0: 0 0
1: 201900 1
2: 403837 2
.
.
19: 3837673 19

The first number is the array index. The last number is the interrupt counter
value when the each interrupt occured. This should be the same as the
array index. The center value is the loop counter value when each
interrupt occured. These should step by about 200,000.

This s a unit test for IRQTrap. It is not a complete unit test because
it uses only a single interrupt. It does not exercise nested interrupts
or window overflow.

Description:
The counter is changed from 1/second to 20/second (50 msec.).
The interrupt vector table is rewritten so that all 15 vectors go to
IRQTrap.
IRQTrap is set only for interrupt 11 from the clock.

Problems:
If a printf() is placed in the IRQDispatch routine the program hangs if
an interrupt occurs during the final printout. printf is not reentrant.