glibc/sysdeps/generic/memcmp.c

377 lines
8.7 KiB
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1995-02-18 01:27:10 +00:00
/* Copyright (C) 1991, 1993, 1995 Free Software Foundation, Inc.
Contributed by Torbjorn Granlund (tege@sics.se).
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. */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#undef __ptr_t
#if defined (__cplusplus) || (defined (__STDC__) && __STDC__)
#define __ptr_t void *
#else /* Not C++ or ANSI C. */
#undef const
#define const
#define __ptr_t char *
#endif /* C++ or ANSI C. */
#if defined (HAVE_STRING_H) || defined (_LIBC)
#include <string.h>
#endif
#ifdef _LIBC
#include <memcopy.h>
#else /* Not in the GNU C library. */
#include <sys/types.h>
/* Type to use for aligned memory operations.
This should normally be the biggest type supported by a single load
and store. Must be an unsigned type. */
#define op_t unsigned long int
#define OPSIZ (sizeof(op_t))
/* Threshold value for when to enter the unrolled loops. */
#define OP_T_THRES 16
/* Type to use for unaligned operations. */
typedef unsigned char byte;
#ifndef WORDS_BIGENDIAN
#define MERGE(w0, sh_1, w1, sh_2) (((w0) >> (sh_1)) | ((w1) << (sh_2)))
#else
#define MERGE(w0, sh_1, w1, sh_2) (((w0) << (sh_1)) | ((w1) >> (sh_2)))
#endif
#endif /* In the GNU C library. */
#ifdef WORDS_BIGENDIAN
#define CMP_LT_OR_GT(a, b) ((a) > (b) ? 1 : -1)
#else
#define CMP_LT_OR_GT(a, b) memcmp_bytes ((a), (b))
#endif
/* BE VERY CAREFUL IF YOU CHANGE THIS CODE! */
/* The strategy of this memcmp is:
1. Compare bytes until one of the block pointers is aligned.
2. Compare using memcmp_common_alignment or
memcmp_not_common_alignment, regarding the alignment of the other
block after the initial byte operations. The maximum number of
full words (of type op_t) are compared in this way.
3. Compare the few remaining bytes. */
#ifndef WORDS_BIGENDIAN
/* memcmp_bytes -- Compare A and B bytewise in the byte order of the machine.
A and B are known to be different.
This is needed only on little-endian machines. */
Thu Jun 13 17:25:11 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/generic/memcmp.c: Add prototype decls for internal fns. * locale/programs/locale.c: Include string.h. * sunrpc/xdr_stdio.c (xdrstdio_getlong), sunrpc/xdr_rec.c (xdrrec_getlong), sunrpc/xdr_mem.c (xdrmem_getlong): Make sure appropriate sign-extension is performed on machines with sizeof(long) > 4. * sunrpc/xdr.c (xdr_int, xdr_u_int): If sizeof(long)==8 and sizeof(int)<sizeof(long), we need to go through a temporary variable. * locale/programs/ld-numeric.c: Include <alloca.h> * libio/stdio.h (__libc_fatal): Add prototype. * libio/cleanup.c: Use __P() to declare prototype when __STDC__ is in efect. * libio/iopopen.c (read_or_write, parent_end, child_end): Declare volatile to avoid "might get clobbered by longjmp" warning. * features.h (__KERNEL_STRICT_NAMES): Define __KERNEL_STRICT_NAMES unless _LOOSE_KERNEL_NAMES is in effect (which, with high probability is a sure loser). * sysdeps/unix/sysv/linux/gnu/types.h (__KERNEL_STRICT_NAMES): Remove. * sysdeps/unix/bsd/osf/alpha/start.S (errno): Removed. * sysdeps/unix/sysv/linux/alpha/start.S: Ditto. * misc/paths.h (_PATH_MAN): Change from /usr/share/man to /usr/man to be Linux FSSTND compliant. Mon Jun 10 17:50:31 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/unix/sysv/linux/alpha/pipe.S: Use PSEUDO. * sysdeps/unix/sysv/linux/alpha/sysdep.S, sysdeps/unix/sysv/linux/alpha/brk.S, sysdeps/unix/sysv/linux/alpha/ieee_get_fp_control.S, sysdeps/unix/sysv/linux/alpha/ieee_set_fp_control.S, sysdeps/unix/sysv/linux/alpha/llseek.S, sysdeps/unix/sysv/linux/alpha/sigsuspend.S, sysdeps/unix/sysv/linux/alpha/syscall.S: Rename syscall_error to __syscall_error to avoid intruding application name space. * sysdeps/unix/sysv/linux/alpha/sysdep.h: Rename __NR_get?id to SYS_get?id so that syscall stubs in sysdeps/unix define these syscalls in terms of getxpid/getxuid/getxgid. * sysdeps/unix/_exit.S, sysdeps/unix/getegid.S, sysdeps/unix/geteuid.S, sysdeps/unix/getppid.S, sysdeps/unix/execve.S, sysdeps/unix/fork.S, sysdeps/unix/syscall.S: Terminate syscall with PSEUDO_END. * sysdeps/unix/make-syscalls.sh, sysdeps/unix/sysdep.h (PSEUDO_END): Rename END() to PSEUDO_END(). * sysdeps/unix/alpha/sysdep.h: Move error-handling code in PSEUDO to PSEUDO_END to improve branch-prediction. Include .frame directive to make syscalls debugabble. (PSEUDO_END): New macro. * sysdeps/unix/alpha/sysdep.h, sysdeps/alpha/bb_init_func.S, sysdeps/unix/sysv/linux/alpha/brk.S: Use ldiq instead of ldi since latter is illegal under DEC Unix. * sysdeps/unix/alpha/sysdep.S: Renamed from sysdeps/unix/sysv/linux/alpha/sysdep.S. This file works for OSF/1 as well. * sysdeps/unix/bsd/osf/alpha/sysdep.S: Remove (note that the EWOULDBLOCK -> EAGAIN mapping was unnecessary since EWOULDBLOCK==EAGAIN under DEC Unix and Linux/Alpha). * sysdeps/alpha/divrem.h: Use retaddr instead of ra as the return address register in the .frame directive. * sysdeps/alpha/copysign.c: Remove. * sunrpc/rpc/types.h: Include <sys/param.h> and <netinet/in.h> to avoid RPC definitions of INADDR_LOOPBACK and/or MAXHOSTNAMELEN. * errno.h: Move __END_DECLS to correct place to make file compilable under c++. * dirent/dirent.h: Document _DIRENT_HAVE_D_OFF macro. Define d_ino only if <direntry.h> hasn't defined d_fileno. * configure.in (HAVE_ASM_WEAKEXT_DIRECTIVE): Reverse order of arguments to weakext to make .weakext detection work on ECOFF systems. * FAQ: Add Linux/Alpha to list of supported platforms. Mention that _validuser() has been replaced by __ivaliduser(). Thu Jun 6 21:39:38 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/unix/bsd/sun/sunos4/tcsetattr.c (tcsetattr): Declare cmd as unsigned long, not as int (to avoid incorrect int->long promotion).
1996-06-19 06:54:12 +00:00
static int memcmp_bytes __P((op_t, op_t));
1995-02-18 01:27:10 +00:00
#ifdef __GNUC__
__inline
#endif
static int
memcmp_bytes (a, b)
op_t a, b;
{
long int srcp1 = (long int) &a;
long int srcp2 = (long int) &b;
op_t a0, b0;
do
{
a0 = ((byte *) srcp1)[0];
b0 = ((byte *) srcp2)[0];
srcp1 += 1;
srcp2 += 1;
}
while (a0 == b0);
return a0 - b0;
}
#endif
Thu Jun 13 17:25:11 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/generic/memcmp.c: Add prototype decls for internal fns. * locale/programs/locale.c: Include string.h. * sunrpc/xdr_stdio.c (xdrstdio_getlong), sunrpc/xdr_rec.c (xdrrec_getlong), sunrpc/xdr_mem.c (xdrmem_getlong): Make sure appropriate sign-extension is performed on machines with sizeof(long) > 4. * sunrpc/xdr.c (xdr_int, xdr_u_int): If sizeof(long)==8 and sizeof(int)<sizeof(long), we need to go through a temporary variable. * locale/programs/ld-numeric.c: Include <alloca.h> * libio/stdio.h (__libc_fatal): Add prototype. * libio/cleanup.c: Use __P() to declare prototype when __STDC__ is in efect. * libio/iopopen.c (read_or_write, parent_end, child_end): Declare volatile to avoid "might get clobbered by longjmp" warning. * features.h (__KERNEL_STRICT_NAMES): Define __KERNEL_STRICT_NAMES unless _LOOSE_KERNEL_NAMES is in effect (which, with high probability is a sure loser). * sysdeps/unix/sysv/linux/gnu/types.h (__KERNEL_STRICT_NAMES): Remove. * sysdeps/unix/bsd/osf/alpha/start.S (errno): Removed. * sysdeps/unix/sysv/linux/alpha/start.S: Ditto. * misc/paths.h (_PATH_MAN): Change from /usr/share/man to /usr/man to be Linux FSSTND compliant. Mon Jun 10 17:50:31 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/unix/sysv/linux/alpha/pipe.S: Use PSEUDO. * sysdeps/unix/sysv/linux/alpha/sysdep.S, sysdeps/unix/sysv/linux/alpha/brk.S, sysdeps/unix/sysv/linux/alpha/ieee_get_fp_control.S, sysdeps/unix/sysv/linux/alpha/ieee_set_fp_control.S, sysdeps/unix/sysv/linux/alpha/llseek.S, sysdeps/unix/sysv/linux/alpha/sigsuspend.S, sysdeps/unix/sysv/linux/alpha/syscall.S: Rename syscall_error to __syscall_error to avoid intruding application name space. * sysdeps/unix/sysv/linux/alpha/sysdep.h: Rename __NR_get?id to SYS_get?id so that syscall stubs in sysdeps/unix define these syscalls in terms of getxpid/getxuid/getxgid. * sysdeps/unix/_exit.S, sysdeps/unix/getegid.S, sysdeps/unix/geteuid.S, sysdeps/unix/getppid.S, sysdeps/unix/execve.S, sysdeps/unix/fork.S, sysdeps/unix/syscall.S: Terminate syscall with PSEUDO_END. * sysdeps/unix/make-syscalls.sh, sysdeps/unix/sysdep.h (PSEUDO_END): Rename END() to PSEUDO_END(). * sysdeps/unix/alpha/sysdep.h: Move error-handling code in PSEUDO to PSEUDO_END to improve branch-prediction. Include .frame directive to make syscalls debugabble. (PSEUDO_END): New macro. * sysdeps/unix/alpha/sysdep.h, sysdeps/alpha/bb_init_func.S, sysdeps/unix/sysv/linux/alpha/brk.S: Use ldiq instead of ldi since latter is illegal under DEC Unix. * sysdeps/unix/alpha/sysdep.S: Renamed from sysdeps/unix/sysv/linux/alpha/sysdep.S. This file works for OSF/1 as well. * sysdeps/unix/bsd/osf/alpha/sysdep.S: Remove (note that the EWOULDBLOCK -> EAGAIN mapping was unnecessary since EWOULDBLOCK==EAGAIN under DEC Unix and Linux/Alpha). * sysdeps/alpha/divrem.h: Use retaddr instead of ra as the return address register in the .frame directive. * sysdeps/alpha/copysign.c: Remove. * sunrpc/rpc/types.h: Include <sys/param.h> and <netinet/in.h> to avoid RPC definitions of INADDR_LOOPBACK and/or MAXHOSTNAMELEN. * errno.h: Move __END_DECLS to correct place to make file compilable under c++. * dirent/dirent.h: Document _DIRENT_HAVE_D_OFF macro. Define d_ino only if <direntry.h> hasn't defined d_fileno. * configure.in (HAVE_ASM_WEAKEXT_DIRECTIVE): Reverse order of arguments to weakext to make .weakext detection work on ECOFF systems. * FAQ: Add Linux/Alpha to list of supported platforms. Mention that _validuser() has been replaced by __ivaliduser(). Thu Jun 6 21:39:38 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/unix/bsd/sun/sunos4/tcsetattr.c (tcsetattr): Declare cmd as unsigned long, not as int (to avoid incorrect int->long promotion).
1996-06-19 06:54:12 +00:00
static int memcmp_common_alignment __P((long, long, size_t));
1995-02-18 01:27:10 +00:00
/* memcmp_common_alignment -- Compare blocks at SRCP1 and SRCP2 with LEN `op_t'
objects (not LEN bytes!). Both SRCP1 and SRCP2 should be aligned for
memory operations on `op_t's. */
#ifdef __GNUC__
__inline
#endif
static int
memcmp_common_alignment (srcp1, srcp2, len)
long int srcp1;
long int srcp2;
size_t len;
{
op_t a0, a1;
op_t b0, b1;
switch (len % 4)
{
case 2:
a0 = ((op_t *) srcp1)[0];
b0 = ((op_t *) srcp2)[0];
srcp1 -= 2 * OPSIZ;
srcp2 -= 2 * OPSIZ;
len += 2;
goto do1;
case 3:
a1 = ((op_t *) srcp1)[0];
b1 = ((op_t *) srcp2)[0];
srcp1 -= OPSIZ;
srcp2 -= OPSIZ;
len += 1;
goto do2;
case 0:
if (OP_T_THRES <= 3 * OPSIZ && len == 0)
return 0;
a0 = ((op_t *) srcp1)[0];
b0 = ((op_t *) srcp2)[0];
goto do3;
case 1:
a1 = ((op_t *) srcp1)[0];
b1 = ((op_t *) srcp2)[0];
srcp1 += OPSIZ;
srcp2 += OPSIZ;
len -= 1;
if (OP_T_THRES <= 3 * OPSIZ && len == 0)
goto do0;
/* Fall through. */
}
do
{
a0 = ((op_t *) srcp1)[0];
b0 = ((op_t *) srcp2)[0];
if (a1 != b1)
return CMP_LT_OR_GT (a1, b1);
do3:
a1 = ((op_t *) srcp1)[1];
b1 = ((op_t *) srcp2)[1];
if (a0 != b0)
return CMP_LT_OR_GT (a0, b0);
do2:
a0 = ((op_t *) srcp1)[2];
b0 = ((op_t *) srcp2)[2];
if (a1 != b1)
return CMP_LT_OR_GT (a1, b1);
do1:
a1 = ((op_t *) srcp1)[3];
b1 = ((op_t *) srcp2)[3];
if (a0 != b0)
return CMP_LT_OR_GT (a0, b0);
srcp1 += 4 * OPSIZ;
srcp2 += 4 * OPSIZ;
len -= 4;
}
while (len != 0);
/* This is the right position for do0. Please don't move
it into the loop. */
do0:
if (a1 != b1)
return CMP_LT_OR_GT (a1, b1);
return 0;
}
Thu Jun 13 17:25:11 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/generic/memcmp.c: Add prototype decls for internal fns. * locale/programs/locale.c: Include string.h. * sunrpc/xdr_stdio.c (xdrstdio_getlong), sunrpc/xdr_rec.c (xdrrec_getlong), sunrpc/xdr_mem.c (xdrmem_getlong): Make sure appropriate sign-extension is performed on machines with sizeof(long) > 4. * sunrpc/xdr.c (xdr_int, xdr_u_int): If sizeof(long)==8 and sizeof(int)<sizeof(long), we need to go through a temporary variable. * locale/programs/ld-numeric.c: Include <alloca.h> * libio/stdio.h (__libc_fatal): Add prototype. * libio/cleanup.c: Use __P() to declare prototype when __STDC__ is in efect. * libio/iopopen.c (read_or_write, parent_end, child_end): Declare volatile to avoid "might get clobbered by longjmp" warning. * features.h (__KERNEL_STRICT_NAMES): Define __KERNEL_STRICT_NAMES unless _LOOSE_KERNEL_NAMES is in effect (which, with high probability is a sure loser). * sysdeps/unix/sysv/linux/gnu/types.h (__KERNEL_STRICT_NAMES): Remove. * sysdeps/unix/bsd/osf/alpha/start.S (errno): Removed. * sysdeps/unix/sysv/linux/alpha/start.S: Ditto. * misc/paths.h (_PATH_MAN): Change from /usr/share/man to /usr/man to be Linux FSSTND compliant. Mon Jun 10 17:50:31 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/unix/sysv/linux/alpha/pipe.S: Use PSEUDO. * sysdeps/unix/sysv/linux/alpha/sysdep.S, sysdeps/unix/sysv/linux/alpha/brk.S, sysdeps/unix/sysv/linux/alpha/ieee_get_fp_control.S, sysdeps/unix/sysv/linux/alpha/ieee_set_fp_control.S, sysdeps/unix/sysv/linux/alpha/llseek.S, sysdeps/unix/sysv/linux/alpha/sigsuspend.S, sysdeps/unix/sysv/linux/alpha/syscall.S: Rename syscall_error to __syscall_error to avoid intruding application name space. * sysdeps/unix/sysv/linux/alpha/sysdep.h: Rename __NR_get?id to SYS_get?id so that syscall stubs in sysdeps/unix define these syscalls in terms of getxpid/getxuid/getxgid. * sysdeps/unix/_exit.S, sysdeps/unix/getegid.S, sysdeps/unix/geteuid.S, sysdeps/unix/getppid.S, sysdeps/unix/execve.S, sysdeps/unix/fork.S, sysdeps/unix/syscall.S: Terminate syscall with PSEUDO_END. * sysdeps/unix/make-syscalls.sh, sysdeps/unix/sysdep.h (PSEUDO_END): Rename END() to PSEUDO_END(). * sysdeps/unix/alpha/sysdep.h: Move error-handling code in PSEUDO to PSEUDO_END to improve branch-prediction. Include .frame directive to make syscalls debugabble. (PSEUDO_END): New macro. * sysdeps/unix/alpha/sysdep.h, sysdeps/alpha/bb_init_func.S, sysdeps/unix/sysv/linux/alpha/brk.S: Use ldiq instead of ldi since latter is illegal under DEC Unix. * sysdeps/unix/alpha/sysdep.S: Renamed from sysdeps/unix/sysv/linux/alpha/sysdep.S. This file works for OSF/1 as well. * sysdeps/unix/bsd/osf/alpha/sysdep.S: Remove (note that the EWOULDBLOCK -> EAGAIN mapping was unnecessary since EWOULDBLOCK==EAGAIN under DEC Unix and Linux/Alpha). * sysdeps/alpha/divrem.h: Use retaddr instead of ra as the return address register in the .frame directive. * sysdeps/alpha/copysign.c: Remove. * sunrpc/rpc/types.h: Include <sys/param.h> and <netinet/in.h> to avoid RPC definitions of INADDR_LOOPBACK and/or MAXHOSTNAMELEN. * errno.h: Move __END_DECLS to correct place to make file compilable under c++. * dirent/dirent.h: Document _DIRENT_HAVE_D_OFF macro. Define d_ino only if <direntry.h> hasn't defined d_fileno. * configure.in (HAVE_ASM_WEAKEXT_DIRECTIVE): Reverse order of arguments to weakext to make .weakext detection work on ECOFF systems. * FAQ: Add Linux/Alpha to list of supported platforms. Mention that _validuser() has been replaced by __ivaliduser(). Thu Jun 6 21:39:38 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/unix/bsd/sun/sunos4/tcsetattr.c (tcsetattr): Declare cmd as unsigned long, not as int (to avoid incorrect int->long promotion).
1996-06-19 06:54:12 +00:00
static int memcmp_not_common_alignment __P((long, long, size_t));
1995-02-18 01:27:10 +00:00
/* memcmp_not_common_alignment -- Compare blocks at SRCP1 and SRCP2 with LEN
`op_t' objects (not LEN bytes!). SRCP2 should be aligned for memory
operations on `op_t', but SRCP1 *should be unaligned*. */
#ifdef __GNUC__
__inline
#endif
static int
memcmp_not_common_alignment (srcp1, srcp2, len)
long int srcp1;
long int srcp2;
size_t len;
{
op_t a0, a1, a2, a3;
op_t b0, b1, b2, b3;
op_t x;
int shl, shr;
/* Calculate how to shift a word read at the memory operation
aligned srcp1 to make it aligned for comparison. */
shl = 8 * (srcp1 % OPSIZ);
shr = 8 * OPSIZ - shl;
/* Make SRCP1 aligned by rounding it down to the beginning of the `op_t'
it points in the middle of. */
srcp1 &= -OPSIZ;
switch (len % 4)
{
case 2:
a1 = ((op_t *) srcp1)[0];
a2 = ((op_t *) srcp1)[1];
b2 = ((op_t *) srcp2)[0];
srcp1 -= 1 * OPSIZ;
srcp2 -= 2 * OPSIZ;
len += 2;
goto do1;
case 3:
a0 = ((op_t *) srcp1)[0];
a1 = ((op_t *) srcp1)[1];
b1 = ((op_t *) srcp2)[0];
srcp2 -= 1 * OPSIZ;
len += 1;
goto do2;
case 0:
if (OP_T_THRES <= 3 * OPSIZ && len == 0)
return 0;
a3 = ((op_t *) srcp1)[0];
a0 = ((op_t *) srcp1)[1];
b0 = ((op_t *) srcp2)[0];
srcp1 += 1 * OPSIZ;
goto do3;
case 1:
a2 = ((op_t *) srcp1)[0];
a3 = ((op_t *) srcp1)[1];
b3 = ((op_t *) srcp2)[0];
srcp1 += 2 * OPSIZ;
srcp2 += 1 * OPSIZ;
len -= 1;
if (OP_T_THRES <= 3 * OPSIZ && len == 0)
goto do0;
/* Fall through. */
}
do
{
a0 = ((op_t *) srcp1)[0];
b0 = ((op_t *) srcp2)[0];
x = MERGE(a2, shl, a3, shr);
if (x != b3)
return CMP_LT_OR_GT (x, b3);
do3:
a1 = ((op_t *) srcp1)[1];
b1 = ((op_t *) srcp2)[1];
x = MERGE(a3, shl, a0, shr);
if (x != b0)
return CMP_LT_OR_GT (x, b0);
do2:
a2 = ((op_t *) srcp1)[2];
b2 = ((op_t *) srcp2)[2];
x = MERGE(a0, shl, a1, shr);
if (x != b1)
return CMP_LT_OR_GT (x, b1);
do1:
a3 = ((op_t *) srcp1)[3];
b3 = ((op_t *) srcp2)[3];
x = MERGE(a1, shl, a2, shr);
if (x != b2)
return CMP_LT_OR_GT (x, b2);
srcp1 += 4 * OPSIZ;
srcp2 += 4 * OPSIZ;
len -= 4;
}
while (len != 0);
/* This is the right position for do0. Please don't move
it into the loop. */
do0:
x = MERGE(a2, shl, a3, shr);
if (x != b3)
return CMP_LT_OR_GT (x, b3);
return 0;
}
int
memcmp (s1, s2, len)
const __ptr_t s1;
const __ptr_t s2;
size_t len;
{
op_t a0;
op_t b0;
long int srcp1 = (long int) s1;
long int srcp2 = (long int) s2;
op_t res;
if (len >= OP_T_THRES)
{
/* There are at least some bytes to compare. No need to test
for LEN == 0 in this alignment loop. */
while (srcp2 % OPSIZ != 0)
{
a0 = ((byte *) srcp1)[0];
b0 = ((byte *) srcp2)[0];
srcp1 += 1;
srcp2 += 1;
res = a0 - b0;
if (res != 0)
return res;
len -= 1;
}
/* SRCP2 is now aligned for memory operations on `op_t'.
SRCP1 alignment determines if we can do a simple,
aligned compare or need to shuffle bits. */
if (srcp1 % OPSIZ == 0)
res = memcmp_common_alignment (srcp1, srcp2, len / OPSIZ);
else
res = memcmp_not_common_alignment (srcp1, srcp2, len / OPSIZ);
if (res != 0)
return res;
/* Number of bytes remaining in the interval [0..OPSIZ-1]. */
srcp1 += len & -OPSIZ;
srcp2 += len & -OPSIZ;
len %= OPSIZ;
}
/* There are just a few bytes to compare. Use byte memory operations. */
while (len != 0)
{
a0 = ((byte *) srcp1)[0];
b0 = ((byte *) srcp2)[0];
srcp1 += 1;
srcp2 += 1;
res = a0 - b0;
if (res != 0)
return res;
len -= 1;
}
return 0;
}
#ifdef weak_alias
#undef bcmp
weak_alias (memcmp, bcmp)
#endif