vm_defs.h

NecluesRTX RTOS的源码

/************************************************************************/
/*                                                                      */
/*              Copyright 1990 by Accelerated Technology                */
/*                                                                      */
/*  PROPRIETARY RIGHTS of Accelerated Technology are involved in the    */
/*  subject matter of this material.  All manufacturing, reproduction,  */
/*  use, and sales rights pertaining to this subject matter are         */
/*  governed by the license agreement.  The buyer or recipient of this  */
/*  package, implicitly accepts the terms of the license.               */
/*                                                                      */
/************************************************************************/

/************************************************************************/
/*                                                                      */
/*  FILE DESCRIPTION                                                    */
/*                                                                      */
/*  This file contains the description of the Variable Length Memory    */
/*  Management structures and associated suspension structures.         */
/*                                                                      */
/*  ROUTINES                                                            */
/*                                                                      */
/*      None                                                            */
/*                                                                      */
/*  NOTES                                                               */
/*                                                                      */
/*      None                                                            */
/*                                                                      */
/************************************************************************/

/* Define the test patterns that are placed on the front and back sides of 
   the memory headers.  Through examination of these fields, nucleus can 
   detect (in most cases) whether or not the header has been corrupted.  */

#define            TOP_PATTERN       0x1234
#define            BOTTOM_PATTERN    0x5678


/* The structure "VM_SUSPENSION_STRUCT" defines the information necessary 
   to suspend a task for memory.  This structure is allocated off of calling 
   application's stack.  */

struct VM_SUSPENSION_STRUCT 
{
    unsigned int             vm_not_used;   /* Not used                 */
    /* Note that the pointers must be one unsigned after the front of the 
       list in order to be compatible with the linked list management.  */
    struct VM_SUSPENSION_STRUCT
                            *vm_next_susp,  /* Next suspension ptr      */
                            *vm_prev_susp;  /* Previous suspension ptr  */
    signed int               vm_task_id;    /* Task suspended           */
    unsigned long            vm_request;    /* Memory requested         */
    unsigned int           **vm_return_addr;/* Address to return value  */
};


/* The structure "VM_BLOCK_HEADER_STRUCT" defines the information necessary 
   for management of a system variable length memory block.  */

struct VM_BLOCK_HEADER_STRUCT 
{
    unsigned int             vm_pattern_1;  /* Test pattern at the top  */
    /* Note that the pointers must be one unsigned after the top of the 
       list in order to be compatible with the linked list management.  */
    struct VM_BLOCK_HEADER_STRUCT
                            *vm_next_block, /* Next block ptr           */
                            *vm_prev_block; /* Previous block ptr       */
    signed int               vm_task_id;    /* Task that allocated it   */
    signed int               vm_in_use;     /* Memory block is in use   */
    unsigned long            vm_block_size; /* Size of available memory, 
                                               in terms of unsigned words  */
    unsigned int             vm_pattern_2;  /* Test pattern on bottom   */
};


/* The structure "VM_BLOCK_TRAILER_STRUCT" defines the trailer block necessary
   for joining free blocks together again and reducing fragmentation.  */
   
struct VM_BLOCK_TRAILER_STRUCT
{
    unsigned int             vm_pattern_1;  /* Test pattern at the top  */
    struct VM_BLOCK_HEADER_STRUCT
                            *vm_header_ptr; /* Block's header pointer   */
    unsigned int             vm_pattern_2;  /* Test pattern on bottom   */
};


/* The structure "VM_LIST_STRUCT" defines the information necessary 
   for management of a linked list.  */

struct VM_LIST_STRUCT 
{
    unsigned int             vm_not_used;   /* Not used for anything    */
    struct VM_LIST_STRUCT   *vm_next_ptr,   /* Next ptr                 */
                            *vm_prev_ptr;   /* Previous ptr             */
};