cpio -S -b flags
Andrew H. Marrinson
andy at icom.UUCP
Sun Sep 7 03:24:25 AEST 1986
> There are two undocumented options, `-S' and `-b', that are supposed
> to be for "swap half words" and "swap both words". I'm not sure under what
> circumstance these switches would be used (swap halfwords only when
> 1/2 word != byte? Swap both when in `pass' mode?). Any explanation?
> --
> Greg Earle UUCP: sdcrdcf!smeagol!earle; attmail!earle
> JPL ARPA: elroy!smeagol!earle at csvax.caltech.edu
Assuming these are the same as in sysV, I believe halfwords refers
(ambiguously) to 16-bit quantites. The -b option does both byte-swapping
and halfword (word) swapping. To summarize then:
byte: 0 1 2 3 4 5 6 7
contents: A B C D E F G H
-s: B A D C F E H G
-S: C D A B G H E F
-b: D C B A H G F E
I seem to recall that when DEC introduced the VAX, longwords (32-bit) were
stored "word-swapped" from the order implied by the multiply/divide
instructions on the PDP-11, or at least from the order used in the PDP-11 C
compiler, thus requiring the -S flag.
I wonder if vn adds the .signature? Just to be safe here it is, possibly
twice:
andy at icom.UUCP
Or for those of Andrew H. Marrinson
you who wish to ICOM Systems, Inc.
play it the hard Arlington Heights, IL 60005
way: ihnp4!icom!andy
--
andy at icom.UUCP
Or for those of Andrew H. Marrinson
you who wish to ICOM Systems, Inc.
play it the hard Arlington Heights, IL 60005
way: ihnp4!icom!andy
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