wordcopy.c

一个C源代码分析器

/* _memcopy.c -- subroutines for memory copy functions.
   Copyright (C) 1991 Free Software Foundation, Inc.
   Contributed by Torbjorn Granlund ([e-mail]).

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

/* BE VERY CAREFUL IF YOU CHANGE THIS CODE...!  */

#include <ansidecl.h>
#include <stddef.h>
#include <memcopy.h>

/* _wordcopy_fwd_aligned -- Copy block beginning at SRCP to
   block beginning at DSTP with LEN `op_t' words (not LEN bytes!).
   Both SRCP and DSTP should be aligned for memory operations on `op_t's.  */

void
DEFUN(_wordcopy_fwd_aligned, (dstp, srcp, len),
      long int dstp AND long int srcp AND size_t len)
{
  op_t a0, a1;

  switch (len % 8)
    {
    case 2:
      a0 = ((op_t *) srcp)[0];
      srcp -= 6 * OPSIZ;
      dstp -= 7 * OPSIZ;
      len += 6;
      goto do1;
    case 3:
      a1 = ((op_t *) srcp)[0];
      srcp -= 5 * OPSIZ;
      dstp -= 6 * OPSIZ;
      len += 5;
      goto do2;
    case 4:
      a0 = ((op_t *) srcp)[0];
      srcp -= 4 * OPSIZ;
      dstp -= 5 * OPSIZ;
      len += 4;
      goto do3;
    case 5:
      a1 = ((op_t *) srcp)[0];
      srcp -= 3 * OPSIZ;
      dstp -= 4 * OPSIZ;
      len += 3;
      goto do4;
    case 6:
      a0 = ((op_t *) srcp)[0];
      srcp -= 2 * OPSIZ;
      dstp -= 3 * OPSIZ;
      len += 2;
      goto do5;
    case 7:
      a1 = ((op_t *) srcp)[0];
      srcp -= 1 * OPSIZ;
      dstp -= 2 * OPSIZ;
      len += 1;
      goto do6;
      
    case 0:
      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
	return;
      a0 = ((op_t *) srcp)[0];
      srcp -= 0 * OPSIZ;
      dstp -= 1 * OPSIZ;
      goto do7;
    case 1:
      a1 = ((op_t *) srcp)[0];
      srcp -=-1 * OPSIZ;
      dstp -= 0 * OPSIZ;
      len -= 1;
      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
	goto do0;
      goto do8;			/* No-op.  */
    }

  do
    {
    do8:
      a0 = ((op_t *) srcp)[0];
      ((op_t *) dstp)[0] = a1;
    do7:
      a1 = ((op_t *) srcp)[1];
      ((op_t *) dstp)[1] = a0;
    do6:
      a0 = ((op_t *) srcp)[2];
      ((op_t *) dstp)[2] = a1;
    do5:
      a1 = ((op_t *) srcp)[3];
      ((op_t *) dstp)[3] = a0;
    do4:
      a0 = ((op_t *) srcp)[4];
      ((op_t *) dstp)[4] = a1;
    do3:
      a1 = ((op_t *) srcp)[5];
      ((op_t *) dstp)[5] = a0;
    do2:
      a0 = ((op_t *) srcp)[6];
      ((op_t *) dstp)[6] = a1;
    do1:
      a1 = ((op_t *) srcp)[7];
      ((op_t *) dstp)[7] = a0;

      srcp += 8 * OPSIZ;
      dstp += 8 * OPSIZ;
      len -= 8;
    }
  while (len != 0);

  /* This is the right position for do0.  Please don't move
     it into the loop.  */
 do0:
  ((op_t *) dstp)[0] = a1;
}

/* _wordcopy_fwd_dest_aligned -- Copy block beginning at SRCP to
   block beginning at DSTP with LEN `op_t' words (not LEN bytes!).
   DSTP should be aligned for memory operations on `op_t's, but SRCP must
   *not* be aligned.  */

void
DEFUN(_wordcopy_fwd_dest_aligned, (dstp, srcp, len),
      long int dstp AND long int srcp AND size_t len)
{
  op_t a0, a1, a2, a3;
  int sh_1, sh_2;

  /* Calculate how to shift a word read at the memory operation
     aligned srcp to make it aligned for copy.  */

  sh_1 = 8 * (srcp % OPSIZ);
  sh_2 = 8 * OPSIZ - sh_1;

  /* Make SRCP aligned by rounding it down to the beginning of the `op_t'
     it points in the middle of.  */
  srcp &= -OPSIZ;

  switch (len % 4)
    {
    case 2:
      a1 = ((op_t *) srcp)[0];
      a2 = ((op_t *) srcp)[1];
      srcp -= 1 * OPSIZ;
      dstp -= 3 * OPSIZ;
      len += 2;
      goto do1;
    case 3:
      a0 = ((op_t *) srcp)[0];
      a1 = ((op_t *) srcp)[1];
      srcp -= 0 * OPSIZ;
      dstp -= 2 * OPSIZ;
      len += 1;
      goto do2;
    case 0:
      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
	return;
      a3 = ((op_t *) srcp)[0];
      a0 = ((op_t *) srcp)[1];
      srcp -=-1 * OPSIZ;
      dstp -= 1 * OPSIZ;
      len += 0;
      goto do3;
    case 1:
      a2 = ((op_t *) srcp)[0];
      a3 = ((op_t *) srcp)[1];
      srcp -=-2 * OPSIZ;
      dstp -= 0 * OPSIZ;
      len -= 1;
      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
	goto do0;
      goto do4;			/* No-op.  */
    }

  do
    {
    do4:
      a0 = ((op_t *) srcp)[0];
      ((op_t *) dstp)[0] = MERGE (a2, sh_1, a3, sh_2);
    do3:
      a1 = ((op_t *) srcp)[1];
      ((op_t *) dstp)[1] = MERGE (a3, sh_1, a0, sh_2);
    do2:
      a2 = ((op_t *) srcp)[2];
      ((op_t *) dstp)[2] = MERGE (a0, sh_1, a1, sh_2);
    do1:
      a3 = ((op_t *) srcp)[3];
      ((op_t *) dstp)[3] = MERGE (a1, sh_1, a2, sh_2);

      srcp += 4 * OPSIZ;
      dstp += 4 * OPSIZ;
      len -= 4;
    }
  while (len != 0);

  /* This is the right position for do0.  Please don't move
     it into the loop.  */
 do0:
  ((op_t *) dstp)[0] = MERGE (a2, sh_1, a3, sh_2);
}

/* _wordcopy_bwd_aligned -- Copy block finishing right before
   SRCP to block finishing right before DSTP with LEN `op_t' words
   (not LEN bytes!).  Both SRCP and DSTP should be aligned for memory
   operations on `op_t's.  */

void
DEFUN(_wordcopy_bwd_aligned, (dstp, srcp, len),
      long int dstp AND long int srcp AND size_t len)
{
  op_t a0, a1;

  switch (len % 8)
    {
    case 2:
      srcp -= 2 * OPSIZ;
      dstp -= 1 * OPSIZ;
      a0 = ((op_t *) srcp)[1];
      len += 6;
      goto do1;
    case 3:
      srcp -= 3 * OPSIZ;
      dstp -= 2 * OPSIZ;
      a1 = ((op_t *) srcp)[2];
      len += 5;
      goto do2;
    case 4:
      srcp -= 4 * OPSIZ;
      dstp -= 3 * OPSIZ;
      a0 = ((op_t *) srcp)[3];
      len += 4;
      goto do3;
    case 5:
      srcp -= 5 * OPSIZ;
      dstp -= 4 * OPSIZ;
      a1 = ((op_t *) srcp)[4];
      len += 3;
      goto do4;
    case 6:
      srcp -= 6 * OPSIZ;
      dstp -= 5 * OPSIZ;
      a0 = ((op_t *) srcp)[5];
      len += 2;
      goto do5;
    case 7:
      srcp -= 7 * OPSIZ;
      dstp -= 6 * OPSIZ;
      a1 = ((op_t *) srcp)[6];
      len += 1;
      goto do6;
      
    case 0:
      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
	return;
      srcp -= 8 * OPSIZ;
      dstp -= 7 * OPSIZ;
      a0 = ((op_t *) srcp)[7];
      goto do7;
    case 1:
      srcp -= 9 * OPSIZ;
      dstp -= 8 * OPSIZ;
      a1 = ((op_t *) srcp)[8];
      len -= 1;
      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
	goto do0;
      goto do8;			/* No-op.  */
    }

  do
    {
    do8:
      a0 = ((op_t *) srcp)[7];
      ((op_t *) dstp)[7] = a1;
    do7:
      a1 = ((op_t *) srcp)[6];
      ((op_t *) dstp)[6] = a0;
    do6:
      a0 = ((op_t *) srcp)[5];
      ((op_t *) dstp)[5] = a1;
    do5:
      a1 = ((op_t *) srcp)[4];
      ((op_t *) dstp)[4] = a0;
    do4:
      a0 = ((op_t *) srcp)[3];
      ((op_t *) dstp)[3] = a1;
    do3:
      a1 = ((op_t *) srcp)[2];
      ((op_t *) dstp)[2] = a0;
    do2:
      a0 = ((op_t *) srcp)[1];
      ((op_t *) dstp)[1] = a1;
    do1:
      a1 = ((op_t *) srcp)[0];
      ((op_t *) dstp)[0] = a0;

      srcp -= 8 * OPSIZ;
      dstp -= 8 * OPSIZ;
      len -= 8;
    }
  while (len != 0);

  /* This is the right position for do0.  Please don't move
     it into the loop.  */
 do0:
  ((op_t *) dstp)[7] = a1;
}

/* _wordcopy_bwd_dest_aligned -- Copy block finishing right
   before SRCP to block finishing right before DSTP with LEN `op_t'
   words (not LEN bytes!).  DSTP should be aligned for memory
   operations on `op_t', but SRCP must *not* be aligned.  */

void
DEFUN(_wordcopy_bwd_dest_aligned, (dstp, srcp, len),
      long int dstp AND long int srcp AND size_t len)
{
  op_t a0, a1, a2, a3;
  int sh_1, sh_2;

  /* Calculate how to shift a word read at the memory operation
     aligned srcp to make it aligned for copy.  */

  sh_1 = 8 * (srcp % OPSIZ);
  sh_2 = 8 * OPSIZ - sh_1;

  /* Make srcp aligned by rounding it down to the beginning of the op_t
     it points in the middle of.  */
  srcp &= -OPSIZ;
  srcp += OPSIZ;

  switch (len % 4)
    {
    case 2:
      srcp -= 3 * OPSIZ;
      dstp -= 1 * OPSIZ;
      a2 = ((op_t *) srcp)[2];
      a1 = ((op_t *) srcp)[1];
      len += 2;
      goto do1;
    case 3:
      srcp -= 4 * OPSIZ;
      dstp -= 2 * OPSIZ;
      a3 = ((op_t *) srcp)[3];
      a2 = ((op_t *) srcp)[2];
      len += 1;
      goto do2;
    case 0:
      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
	return;
      srcp -= 5 * OPSIZ;
      dstp -= 3 * OPSIZ;
      a0 = ((op_t *) srcp)[4];
      a3 = ((op_t *) srcp)[3];
      goto do3;
    case 1:
      srcp -= 6 * OPSIZ;
      dstp -= 4 * OPSIZ;
      a1 = ((op_t *) srcp)[5];
      a0 = ((op_t *) srcp)[4];
      len -= 1;
      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
	goto do0;
      goto do4;			/* No-op.  */
    }

  do
    {
    do4:
      a3 = ((op_t *) srcp)[3];
      ((op_t *) dstp)[3] = MERGE (a0, sh_1, a1, sh_2);
    do3:
      a2 = ((op_t *) srcp)[2];
      ((op_t *) dstp)[2] = MERGE (a3, sh_1, a0, sh_2);
    do2:
      a1 = ((op_t *) srcp)[1];
      ((op_t *) dstp)[1] = MERGE (a2, sh_1, a3, sh_2);
    do1:
      a0 = ((op_t *) srcp)[0];
      ((op_t *) dstp)[0] = MERGE (a1, sh_1, a2, sh_2);

      srcp -= 4 * OPSIZ;
      dstp -= 4 * OPSIZ;
      len -= 4;
    }
  while (len != 0);

  /* This is the right position for do0.  Please don't move
     it into the loop.  */
 do0:
  ((op_t *) dstp)[3] = MERGE (a0, sh_1, a1, sh_2);
}