xio_dcr.c

基于Xilinx-XUPV2P开发平台的嵌入式系统实验例程：实验4编写基本的应用程序

/* $Id: xio_dcr.c,v 1.15 2005/10/06 15:51:52 meinelte Exp $ */
/******************************************************************************
*
*       XILINX IS PROVIDING THIS DESIGN, CODE, OR INFORMATION "AS IS"
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*       (c) Copyright 2002 Xilinx Inc.
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******************************************************************************/
/*****************************************************************************/
/**
*
* @file xio_dcr.c
*
* The implementation of the XDcrIo interface. See xio_dcr.h for more
* information about the component.
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver   Who  Date     Changes
* ----- ---- -------- -----------------------------------------------
* 1.00a ecm  10/18/01 First release
*       ecm  01/29/03 Cleaned up the table and made it more readable.
*                     The DCR_REG_512 was 17 and the table used DCR_REG_32
*                     +15 which is actually the same as what DCR_REG_512
*                     should have been,16. I removed the blocks using
*                     DCR_REG_32+15 and added blocks using DCR_REG_512+14
*                     to make the table correct when DCR_REG_512 = 16.
*                     This is functionally exactly the same, just more
*                     readable hence no rev bump.
*       ecm  09/21/05 Fixed the function calls into the table to allow
*                     the code to be optimized. Also added the directive
*                     to force the code into the text space for Linux to
*                     function without causing a page fault.
* </pre>
*
* @internal
*
* The C functions which subsequently call into either the assembly code or into
* the provided table of functions are required since the registers assigned to
* the calling and return from functions are strictly defined in the ABI and that
* definition is used in the low-level functions directly. The use of macros is
* not recommended since the temporary registers in the ABI are defined but there
* is no way to force the compiler to use a specific register in a block of code.
*
*****************************************************************************/

/***************************** Include Files ********************************/

#include "xstatus.h"
#include "xbasic_types.h"
#include "xio.h"
#include "xio_dcr.h"

/************************** Constant Definitions ****************************/

#define SUB_RETURN                  0x4E800020  /* equals 'blr' */
#define MTDCR_FIXED                 0x7C000386  /* this is the basic template*/
                                                /* equals 'mtdcr 0, 0x00' */
#define MFDCR_FIXED                 0x7C000286  /* this is the basic template*/
                                                /* equals 'mfdcr 0, 0x00' */
#define GPR_SHIFT                   21
#define DCR_SHIFT_LH                16          /* bits 5 - 9 shift value */
#define DCR_SHIFT_UH                11          /* bits 0 - 4 shift value */
#define DCR_REG_32                   1          /* register 32 and above */
#define DCR_REG_512                 16          /* register 512 and above */

/* defines for the mfdcr and mfdcr structures */

#define GPR_SOURCE_REG              4<<GPR_SHIFT
#define GPR_DEST_REG                3<<GPR_SHIFT


/**************************** Type Definitions ******************************/
typedef Xuint32 (*XIo_DcrOpCode)(Xuint32 Register, Xuint32 Data);


typedef struct DcrFunctionTableEntryTag
{
    Xuint32 OpCode;
    Xuint32 Return;
} DcrFunctionTableEntry;


#if defined __GNUC__
#if defined XPAR_XIO_DCR_TEXT_SPACE
static DcrFunctionTableEntry __attribute__((section(".text")))MtDcrTable[MAX_DCR_REGISTERS] =
#else
static DcrFunctionTableEntry MtDcrTable[MAX_DCR_REGISTERS] =
#endif
#else
static DcrFunctionTableEntry MtDcrTable[MAX_DCR_REGISTERS] =
#endif
{
  {MTDCR_FIXED | GPR_SOURCE_REG | (0)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (1)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (2)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (3)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (4)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (5)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (6)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (7)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (8)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (9)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (10)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (11)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (12)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (13)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (14)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (15)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (16)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (17)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (18)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (19)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (20)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (21)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (22)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (23)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (24)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (25)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (26)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (27)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (28)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (29)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (30)<<DCR_SHIFT_LH,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | (31)<<DCR_SHIFT_LH,SUB_RETURN},
  /* this is where the DCR register numbering goes weird*/
  /* 32 through 63 */

  {MTDCR_FIXED | GPR_SOURCE_REG | ((0)<<DCR_SHIFT_LH)|((DCR_REG_32+0)<<DCR_SHIFT_UH) ,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | ((1)<<DCR_SHIFT_LH)|((DCR_REG_32+0)<<DCR_SHIFT_UH) ,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | ((2)<<DCR_SHIFT_LH)|((DCR_REG_32+0)<<DCR_SHIFT_UH) ,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | ((3)<<DCR_SHIFT_LH)|((DCR_REG_32+0)<<DCR_SHIFT_UH) ,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | ((4)<<DCR_SHIFT_LH)|((DCR_REG_32+0)<<DCR_SHIFT_UH) ,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | ((5)<<DCR_SHIFT_LH)|((DCR_REG_32+0)<<DCR_SHIFT_UH) ,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | ((6)<<DCR_SHIFT_LH)|((DCR_REG_32+0)<<DCR_SHIFT_UH) ,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | ((7)<<DCR_SHIFT_LH)|((DCR_REG_32+0)<<DCR_SHIFT_UH) ,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | ((8)<<DCR_SHIFT_LH)|((DCR_REG_32+0)<<DCR_SHIFT_UH) ,SUB_RETURN},
  {MTDCR_FIXED | GPR_SOURCE_REG | ((9)<<DCR_SHIFT_LH)|((DCR_REG_32+0)<<DCR_SHIFT_UH) ,SUB_RETURN},