1 files changed, 33 insertions, 0 deletions
diff --git a/src/slalib/range.f b/src/slalib/range.f
new file mode 100644
index 0000000..a3684cb
--- /dev/null
+++ b/src/slalib/range.f
@@ -0,0 +1,33 @@
+      REAL FUNCTION sla_RANGE (ANGLE)
+*+
+*     - - - - - -
+*      R A N G E
+*     - - - - - -
+*
+*  Normalize angle into range +/- pi  (single precision)
+*
+*  Given:
+*     ANGLE     dp      the angle in radians
+*
+*  The result is ANGLE expressed in the +/- pi (single
+*  precision).
+*
+*  P.T.Wallace   Starlink   23 November 1995
+*
+*  Copyright (C) 1995 Rutherford Appleton Laboratory
+*-
+
+      IMPLICIT NONE
+
+      REAL ANGLE
+
+      REAL API,A2PI
+      PARAMETER (API=3.141592653589793238462643)
+      PARAMETER (A2PI=6.283185307179586476925287)
+
+
+      sla_RANGE=MOD(ANGLE,A2PI)
+      IF (ABS(sla_RANGE).GE.API)
+     :          sla_RANGE=sla_RANGE-SIGN(A2PI,ANGLE)
+
+      END