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- *DECK R9UPAK
- SUBROUTINE R9UPAK (X, Y, N)
- C***BEGIN PROLOGUE R9UPAK
- C***PURPOSE Unpack a floating point number X so that X = Y*2**N.
- C***LIBRARY SLATEC (FNLIB)
- C***CATEGORY A6B
- C***TYPE SINGLE PRECISION (R9UPAK-S, D9UPAK-D)
- C***KEYWORDS FNLIB, UNPACK
- C***AUTHOR Fullerton, W., (LANL)
- C***DESCRIPTION
- C
- C Unpack a floating point number X so that X = Y*2.0**N, where
- C 0.5 .LE. ABS(Y) .LT. 1.0.
- C
- C***REFERENCES (NONE)
- C***ROUTINES CALLED (NONE)
- C***REVISION HISTORY (YYMMDD)
- C 780701 DATE WRITTEN
- C 861211 REVISION DATE from Version 3.2
- C 891214 Prologue converted to Version 4.0 format. (BAB)
- C***END PROLOGUE R9UPAK
- C***FIRST EXECUTABLE STATEMENT R9UPAK
- ABSX = ABS(X)
- N = 0
- IF (X.EQ.0.0E0) GO TO 30
- C
- 10 IF (ABSX.GE.0.5E0) GO TO 20
- N = N-1
- ABSX = ABSX*2.0E0
- GO TO 10
- C
- 20 IF (ABSX.LT.1.0E0) GO TO 30
- N = N+1
- ABSX = ABSX*0.5E0
- GO TO 20
- C
- 30 Y = SIGN(ABSX,X)
- RETURN
- C
- END
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