From fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 Mon Sep 17 00:00:00 2001
From: Joseph Hunkeler <jhunkeler@gmail.com>
Date: Wed, 8 Jul 2015 20:46:52 -0400
Subject: Initial commit

---
 sys/gio/fpfixr.x | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 sys/gio/fpfixr.x

(limited to 'sys/gio/fpfixr.x')

diff --git a/sys/gio/fpfixr.x b/sys/gio/fpfixr.x
new file mode 100644
index 00000000..fe67c5b8
--- /dev/null
+++ b/sys/gio/fpfixr.x
@@ -0,0 +1,43 @@
+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	<mach.h>
+
+# FP_FIXR -- The following procedure is equivalent to "int(x)", except that
+# it preserves the most significant digits of x, when x is greater than the
+# largest integer.  For example, if an integer is 32 bits and X has a 58 bit
+# mantissa, "int(x)" would cause nearly half the precision to be lost.
+# 
+# Algorithm (x is assumed nonnegative):
+#    (1) find high, low x such that  x = highx + lowx
+#	and highx contains the extra digits of precision.
+#    (2) subtract highx from x, and truncate the residual by assignment
+#	into a long integer.
+#    (3) add truncated lowx and highx to get high precision truncated
+#	real or double result.
+
+real procedure fp_fixr (x)
+
+real	x
+real	absx, highx, scaledx
+int	expon
+long	longx, lowx
+
+begin
+	absx = abs (x)
+	scaledx = absx
+	expon = 0
+
+	while (scaledx > MAX_LONG) {
+	    scaledx = scaledx / 10.0E0
+	    expon = expon + 1
+	}
+
+	longx = scaledx
+	highx = longx * (10.0E0 ** expon)
+	lowx = absx - highx
+
+	if (x > 0)
+	    return (highx + lowx)
+	else
+	    return (-highx - lowx)
+end
-- 
cgit