thread.hxx

ecos为实时嵌入式操作系统

#ifndef CYGONCE_KERNEL_THREAD_HXX
#define CYGONCE_KERNEL_THREAD_HXX

//==========================================================================
//
//      thread.hxx
//
//      Thread class declarations
//
//==========================================================================
//####COPYRIGHTBEGIN####
//
// -------------------------------------------
// The contents of this file are subject to the Cygnus eCos Public License
// Version 1.0 (the "License"); you may not use this file except in
// compliance with the License.  You may obtain a copy of the License at
// http://sourceware.cygnus.com/ecos
// 
// Software distributed under the License is distributed on an "AS IS"
// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See the
// License for the specific language governing rights and limitations under
// the License.
// 
// The Original Code is eCos - Embedded Cygnus Operating System, released
// September 30, 1998.
// 
// The Initial Developer of the Original Code is Cygnus.  Portions created
// by Cygnus are Copyright (C) 1998,1999 Cygnus Solutions.  All Rights Reserved.
// -------------------------------------------
//
//####COPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):   nickg
// Contributors:        nickg
// Date:        1997-09-09
// Purpose:     Define Thread class interfaces
// Description: The classes defined here collectively implement the
//              internal API used to create, configure and manage threads.
// Usage:       #include <cyg/kernel/thread.hxx>
//
//####DESCRIPTIONEND####
//
//==========================================================================

#include <cyg/kernel/ktypes.h>
#include <cyg/infra/cyg_ass.h>         // assertion macros
#include <cyg/kernel/sched.hxx>
#include <cyg/kernel/clock.hxx>
#include <cyg/kernel/except.hxx>

#include <cyg/hal/hal_arch.h>

// -------------------------------------------------------------------------
// Miscellaneous types

typedef void cyg_thread_entry(CYG_ADDRWORD data);// Thread entry point function

// -------------------------------------------------------------------------
// Hardware thread interface.
// The implementation of this class is provided by the HAL.

class Cyg_HardwareThread
{
    friend class Cyg_Scheduler;

protected:

    CYG_ADDRESS         stack_base;     // pointer to base of stack area

    cyg_uint32          stack_size;     // size of stack area in bytes

#ifdef CYGFUN_KERNEL_THREADS_STACK_LIMIT
    CYG_ADDRESS         stack_limit;    // movable stack limit
#endif    

    CYG_ADDRESS         stack_ptr;      // pointer to saved state on stack

    cyg_thread_entry    *entry_point;   // main entry point (code pointer!)

    CYG_ADDRWORD        entry_data;     // entry point argument

#ifdef CYGDBG_KERNEL_DEBUG_GDB_THREAD_SUPPORT

    HAL_SavedRegisters  *saved_context; // If non-zero, this points at a more
                                        // interesting context than stack_ptr.
#endif
    
    Cyg_HardwareThread(
        cyg_thread_entry        *entry_point,   // entry point function
        CYG_ADDRWORD            entry_data,     // entry data
        cyg_ucount32            stack_size = 0, // stack size, 0 = use default
        CYG_ADDRESS             stack_base = 0  // stack base, NULL = allocate
    );

    // Thread entry point. This is where all threads begin execution.
    // This routine does a little housekeeping and then call the main
    // entry_point specified above.
    static void thread_entry(Cyg_Thread *thread);

    // Initialize the context of the thread to start execution at thread_entry
    void    init_context( Cyg_Thread *thread );
    
    // Save current thread's context and load that of the given next thread.
    void    switch_context(Cyg_HardwareThread *next);

    // load this thread's context without saving current context
    void    load_context();

    // attach a stack to this thread
    void    attach_stack(CYG_ADDRESS stack, cyg_uint32 stack_size);

    // detach the stack from this thread
    CYG_ADDRESS detach_stack();

    // Adjust the thread's saved state to call the exception
    // handler when next executed.
    void    prepare_exception (
        cyg_exception_handler   *exception_handler,
        CYG_ADDRWORD            exception_data,
        cyg_code                exception_number,
        CYG_ADDRWORD            exception_info
        );

public:

    CYGDBG_DEFINE_CHECK_THIS    

    // Get and set entry_data.

    void set_entry_data( CYG_ADDRWORD data );

    CYG_ADDRWORD get_entry_data();

#ifdef CYGDBG_KERNEL_DEBUG_GDB_THREAD_SUPPORT    
    // Return the current saved state for this thread.
    HAL_SavedRegisters *get_saved_context();

    // Set the saved context pointer.
    void set_saved_context(HAL_SavedRegisters *ctx);
#endif

    // get the size/base of this thread's stack
    CYG_ADDRESS get_stack_base();

    cyg_uint32 get_stack_size();

#ifdef CYGFUN_KERNEL_THREADS_STACK_LIMIT    
    // Allocate some memory at the lower end of the stack
    // by moving the stack limit pointer.

    void *increment_stack_limit( cyg_ucount32 size);
    
    CYG_ADDRESS get_stack_limit();
#endif    
};

// -------------------------------------------------------------------------
// Per-thread timer support class.
// This is only included when required.

#ifdef CYGFUN_KERNEL_THREADS_TIMER

class Cyg_ThreadTimer
    : public Cyg_Alarm
{
    friend class Cyg_Thread;

    // Pointer to current thread
    Cyg_Thread          *thread;

    // Constructor
    Cyg_ThreadTimer(
        Cyg_Thread      *thread
        );

    // Alarm function
    static void alarm( Cyg_Alarm *alarm, CYG_ADDRWORD data);

    CYGDBG_DEFINE_CHECK_THIS

};

#endif

// -------------------------------------------------------------------------
// Main Thread class.
// This provides the public API for controlling threads.

class Cyg_Thread
    : public Cyg_HardwareThread,       // provides hardware abstractions
      public Cyg_SchedThread           // provides scheduling abstractions
{
    friend class Cyg_Scheduler;
    friend void deliver_exception( CYG_WORD code, CYG_ADDRWORD data );
    
    // The following definitions are used by all variants of the
    // basic thread object.

public:    
    enum {                       // Thread state values
        
        RUNNING    = 0,          // Thread is runnable or running
        SLEEPING   = 1,          // Thread is waiting for something to happen
        COUNTSLEEP = 2,          // Sleep in counted manner
        SUSPENDED  = 4,          // Suspend count is non-zero
        CREATING   = 8,          // Thread is being created
        EXITED     = 16,         // Thread has exited

        // This is the set of bits that must be cleared by a generic
        // wake() or release().
        SLEEPSET   = (SLEEPING | COUNTSLEEP)
    };
    
private:
    // Current thread state, a logical OR of the above values.
    // Only if this word is zero can the thread execute.
    cyg_uint32                  state;      

    // Suspension counter, if > 0, the thread is suspended
    cyg_ucount32                suspend_count;

    // Wakeup counter, if > 0, sleep will not sleep, just decrement
    cyg_ucount32                wakeup_count;

    // A word of data used in syncronization object to communicate
    // information between sleepers and wakers.
    CYG_ADDRWORD                wait_info;
    
    // Unique thread id assigned on creation
    cyg_uint16                  unique_id;

#ifdef CYGPKG_KERNEL_EXCEPTIONS

    // If exceptions are supported, define an exception control
    // object that will be used to manage and deliver them. If
    // exceptions are global there is a single static instance
    // of this object, if they are per-thread then there is one
    // for each thread.
private:

#ifdef CYGSEM_KERNEL_EXCEPTIONS_GLOBAL
    static
#endif
    Cyg_Exception_Control       exception_control;

public:

    static void register_exception(
        cyg_code                exception_number,       // exception number
        cyg_exception_handler   handler,                // handler function
        CYG_ADDRWORD            data,                   // data argument
        cyg_exception_handler   **old_handler,          // handler function
        CYG_ADDRWORD            *old_data               // data argument
        );

    static void deregister_exception(
        cyg_code                exception_number        // exception number
        );
    
    void deliver_exception(
        cyg_code            exception_number,       // exception being raised
        CYG_ADDRWORD        exception_info          // exception specific info
        );

#endif

    
public:

    CYGDBG_DEFINE_CHECK_THIS