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/***
*swab.c - block copy, while swapping even/odd bytes
*
* Copyright (c) 1989-1991, Microsoft Corporation. All rights reserved.
*
*Purpose:
* This module contains the routine _swab() which swaps the odd/even
* bytes of words during a block copy.
*
*Revision History:
* 06-02-89 PHG module created, based on asm version
* 03-06-90 GJF Fixed calling type, added #include <cruntime.h> and
* fixed copyright. Also, cleaned up the formatting a
* bit.
* 09-27-90 GJF New-style function declarators.
* 01-21-91 GJF ANSI naming.
*
*******************************************************************************/
#include <cruntime.h>
#include <stdlib.h>
/***
*void _swab(srcptr, dstptr, nbytes) - swap ODD/EVEN bytes during word move
*
*Purpose:
* This routine copys a block of words and swaps the odd and even
* bytes. nbytes must be > 0, otherwise nothing is copied. If
* nbytes is odd, then only (nbytes-1) bytes are copied.
*
*Entry:
* srcptr = pointer to the source block
* dstptr = pointer to the destination block
* nbytes = number of bytes to swap
*
*Returns:
* None.
*
*Exceptions:
*
*******************************************************************************/
void _CALLTYPE1 _swab (
char *src,
char *dest,
int nbytes
)
{
char b1, b2;
while (nbytes > 1) {
b1 = *src++;
b2 = *src++;
*dest++ = b2;
*dest++ = b1;
nbytes -= 2;
}
}
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