Initial commit

1 files changed, 41 insertions, 0 deletions

diff --git a/sys/gio/fpequald.x b/sys/gio/fpequald.x
new file mode 100644
index 00000000..ba6f75a2
--- /dev/null
+++ b/sys/gio/fpequald.x
@@ -0,0 +1,41 @@
+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	<mach.h>
+
+# FP_EQUALD -- The following procedure is used to compare two double precision
+# numbers for equality to within the machine precision for doubles.  A simple
+# comparison of the difference of the two numbers with the machine epsilon
+# does not suffice unless the numbers are first normalized to near 1.0, the
+# constant used to compute the machine epsilon (epsilon is the smallest number
+# such that 1.0 + epsilon > 1.0).
+
+bool procedure fp_equald (x, y)
+
+double	x, y
+double	x1, x2, normx, normy, tol
+int	ex, ey
+
+begin
+	# Check for the obvious first.
+	if (x == y)
+	    return (true)
+
+	# We can't normalize zero, so handle the zero operand cases first.
+	# Note that the case 0 equals 0 is handled above.
+
+	if (x == 0.0D0 || y == 0.0D0)
+	    return (false)
+
+	# Normalize operands and do an epsilon compare.
+	call fp_normd (x, normx, ex)
+	call fp_normd (y, normy, ey)
+
+	if (ex != ey)
+	    return (false)
+	else {
+	    tol = EPSILOND * 32.0D0
+	    x1 = 1.0D0 + abs (normx - normy)
+	    x2 = 1.0D0 + tol
+	    return (x1 <= x2)
+	}
+end