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piscal/dataassim/math/numrec/f77_sources/psdes.for
T
2016-02-03 18:52:05 +00:00

20 lines
653 B
Fortran

SUBROUTINE psdes(lword,irword)
INTEGER irword,lword,NITER
PARAMETER (NITER=4)
INTEGER i,ia,ib,iswap,itmph,itmpl,c1(4),c2(4)
SAVE c1,c2
DATA c1 /16#BAA96887,16#1E17D32C,16#03BCDC3C,16#0F33D1B2/, c2
*/16#4B0F3B58,16#E874F0C3,16#6955C5A6, 16#55A7CA46/
do 11 i=1,NITER
iswap=irword
ia=ieor(irword,c1(i))
itmpl=iand(ia,65535)
itmph=iand(ishft(ia,-16),65535)
ib=itmpl**2+not(itmph**2)
ia=ior(ishft(ib,16),iand(ishft(ib,-16),65535))
irword=ieor(lword,ieor(c2(i),ia)+itmpl*itmph)
lword=iswap
11 continue
return
END