M436: Pack Bytes into Full Words

Author(s): CDC: J. Blake, IBM: A.Berglund	Library: KERNLIB
Submitter:	Submitted: 20.10.1975
Language: Fortran or Assembler	Revised: 01.02.1982

BUNCH converts a source array containing NBYTES bytes of NBITS bits per byte (where each byte is stored right-adjusted in a full word), into a target array in which the bytes follow each other contiguously without intermediate padding. The last word of the target array, if incomplete, is however padded with binary zero. BUNCH is the inverse of BLOW (M426).

Structure:

SUBROUTINE subprogram
User Entry Names: BUNCH
External References: PKCHAR

Usage:

    CALL BUNCH(SOURCE,TARGET,NBYTES,NBITS)

SOURCE

Source array containing NBYTES bytes, each right-adjusted in a full word.

TARGET

Target array, which must be at least (rounded up to an integral value) words long, where on CDC and on IBM.

NBYTES

Number of bytes in the source array .

NBITS

Number of bits per byte .

Restrictions:

The arrays SOURCE and TARGET must not overlap in any way.

Error handling:

BUNCH ignores calls with erroneous parameter values.

Examples:

IBM:

    CALL BUNCH(SOURCE,TARGET,200,16)

The array SOURCE contains 200 words, each containing an 16-bit byte, right-adjusted. After returning from BUNCH, the array TARGET will contain 100 32-bit words, in which the 200 16-bit bytes are stored contiguously.