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/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
*/
#define import_spp
#define import_knames
#include <iraf.h>
/*
* BITFIELDS.C -- Portable C routines for extracting and inserting small
* integers into an integer value.
*/
XUINT bitmask[] = { 0, /* MACHDEP */
01, 03, 07,
017, 037, 077,
0177, 0377, 0777,
01777, 03777, 07777,
017777, 037777, 077777,
0177777, 0377777, 0777777,
01777777, 03777777, 07777777,
017777777, 037777777, 077777777,
0177777777, 0377777777, 0777777777,
01777777777, 03777777777, 07777777777,
017777777777, 037777777777, 077777777777,
0177777777777, 0377777777777, 0777777777777,
01777777777777, 03777777777777, 07777777777777,
017777777777777, 037777777777777, 077777777777777,
0177777777777777, 0377777777777777, 0777777777777777,
01777777777777777, 03777777777777777, 07777777777777777,
017777777777777777, 037777777777777777, 077777777777777777,
0177777777777777777, 0377777777777777777, 0777777777777777777,
01777777777777777777, 03777777777777777777, 07777777777777777777,
017777777777777777777, 037777777777777777777, 077777777777777777777,
0177777777777777777777, 0377777777777777777777, 0777777777777777777777,
01777777777777777777777
};
/* BITPAK -- Pack an unsigned integer value into a bitfield in a longword.
* The size of the bitfield may not exceed the number of bits in an integer.
*/
void
BITPAK (
XUINT *ival, /* value to be placed in bitfield */
XUINT *wordp, /* longword to be written into */
XINT *offset, /* one-indexed offset of first bit */
XINT *nbits /* number of bits to be set */
)
{
register XUINT shift;
register XUINT mask;
shift = *offset - 1;
mask = bitmask[*nbits] << shift;
*wordp = (*wordp & ~mask) | ((*ival << shift) & mask);
}
/* BITUPK -- Unpack an unsigned integer bit field from a longword.
*/
XINT
BITUPK (
XUINT *wordp, /* longword to be examined */
XINT *offset, /* one-indexed offset of first bit */
XINT *nbits /* number of bits to be set */
)
{
return ((*wordp >> (*offset-1)) & bitmask[*nbits]);
}
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