diff options
Diffstat (limited to 'sys/osb/bitfields.c')
| -rw-r--r-- | sys/osb/bitfields.c | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/sys/osb/bitfields.c b/sys/osb/bitfields.c new file mode 100644 index 00000000..3275c542 --- /dev/null +++ b/sys/osb/bitfields.c @@ -0,0 +1,70 @@ +/* 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. + */ + +unsigned XINT 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, 03777777777777777777777, 07777777777777777777777 +}; + + + +/* 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 ( + unsigned XINT *ival, /* value to be placed in bitfield */ + unsigned XINT *wordp, /* longword to be written into */ + XINT *offset, /* one-indexed offset of first bit */ + XINT *nbits /* number of bits to be set */ +) +{ + register unsigned XINT shift; + register unsigned XINT 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 ( + unsigned XINT *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]); +} |