【请教】计算机专业或者懂操作系统的XD请进...

方天虹

上课都听得懂...但是出来的题目就是不明白要我做什么...大家帮忙看看...

In this assignment, you will implement a program to  handle  con-
current  processes which perform arithmetic operations.
This is especially applicable for execution in dual or quad-core
computer systems.

You will learn concepts from  several  computer  science  discip-
lines, including compilers, data flow architecture, parallel com-
putation, and, of course, operating systems.  The input to your
program is illustrated by the following example:

  main()
  {  input_var a,b,c,d;
     process_var p1,p2,p3,p4;
         
     read(a,b,c,d);
     cobegin
        p1 = a + b;
        p2 = c - d;
        p3 = a + 2;
     coend;
     p4 = p1 * (p2 + p3);
     write(a,b,c,d,p1,p2,p3,p4);
  }

The syntax of the concurrent program follows that of C with the
following extensions.

input_var declares input variables to be read by your program
using "read".   process_var  declares  process  variables
whose  values  will be computed a process you create.  There will
be a distinct process to handle the calculation for each  process
variable.  Statements within a cobegin-coend pair can be executed
concurrently.  Therefore, processes  which  compute  the  process
variables  in  these  concurrent  statements can be executed con-
currently.
            In the above example, processes to compute the values
of p1, p2, and p3 can be executed concurrently.  However, these 3
processes must complete before the process for computing  p4  can
start. There can be several levels of nesting cobegin-coend pairs
and your program should parse these  statements  correctly. There
may be one level of parantheses in one arithmetic operation, and
this also imposes precedence constraints on the processes'
arithmetic operations.

You may want to create an  internal precedence graph to store the
dependencies among the  processes.   To  synchronize  these  con-
current processes, you are to use Unix semaphores.  The output of
your program consists of a printout of the values  of  all  input
and process variables as specified by "write".

有任何idea都好哦!!!

方天虹

顶上去!!! 任何方向指引都好哦!!

sammycheung

题都能出这么长,我PF老美了.
问题是不是在这段,偶看不懂.
You may want to create an  internal precedence graph to store the
dependencies among the  processes.   To  synchronize  these  con-
current processes, you are to use Unix semaphores.  The output of
your program consists of a printout of the values  of  all  input
and process variables as specified by "write".