yield汇编实现

yield汇编实现.

　

#include <stdio.h
#include <conio.h
#include <iostream.h

//
// marks a location in the program for resume
// does not return control, exits function from inside macro
//
// yield( x, ret )
//      x : the 'name' of the yield, cannot be ambiguous in the
//          function namespace
//    ret : the return value for when yield() exits the function;

//          must match function return type (leave blank for no return type)

#define yield(x,ret)                            \
    {                                           \
        /* store the resume location */         \
        __asm {                                 \
            mov _myStaticMkr,offset label_##x   \
        }                                       \
                                                \
        /* return the supplied value */         \
        return ret;                             \
    }                                           \
    /* our offset in the function */            \
    label_##x:

//
// resumes function from the stored offset, or
// continues without notice if there's not one
// stored
//
// resume()
//   <void

#define resume()                        \
    /* our stored offset */             \
    static _myStaticMkr=;              \
                                        \
    /* test for no offset */            \
    if( _myStaticMkr )                  \
    {                                   \
        /* resume from offset */        \
        __asm                           \
        {                               \
            jmp _myStaticMkr            \
        }                               \
    }

// example demonstrating a function with an int return type
// using the yield() and resume() macros
//
// myFunc()
//   <void

int myFunc()
{
    resume();

    cout << "1\n";

    yield(,);

    cout << "2\n";

    yield(,);

    cout << "3\n";

    yield(,);

    cout << "4\n";

    return ;
}

// main function
//
// main()
//   <void

void main( void )
{
    cout << "Yield in C++\n";
    cout << "Chris Pergrossi\n\n";

    myFunc();

    do

    {
        cout << "main()\n";
        cout.flush();
    } while( myFunc() );

    cout.flush();

    getch();
}

/*

// example demonstrating a function with no return type
// using the yield() and resume() macros
//
// myFunc()
//   <void

void myFunc()
{
    resume();

    cout << "1\n";

    yield(1);

    cout << "2\n";

    yield(2);

    cout << "3\n";

    yield(3);

    cout << "4\n";

    return;
}

// main function
//
// main()
//   <void

void main( void )
{
    cout << "Yield in C++\n";
    cout << "Chris Pergrossi\n\n";

    myFunc();

    for( int k = 0; k < 4; k ++ )
    {
        cout << "main()\n";
        cout.flush();

        myFunc();
    }

    cout.flush();

    getch();
}

*/