X-Git-Url: http://shamusworld.gotdns.org/cgi-bin/gitweb.cgi?p=rmac;a=blobdiff_plain;f=fltpoint.c;h=8739e88c1500d73397e6974df8c506377ee2e91a;hp=fa1eb41ad9c78af887a63b444f099a4ecf184d95;hb=29fa5dcf504b966803063a1c2891f58f97126d04;hpb=9153334781cd2e23750f4dc002e847606c07a1f0

diff --git a/fltpoint.c b/fltpoint.c
index fa1eb41..8739e88 100644
--- a/fltpoint.c
+++ b/fltpoint.c
@@ -2,7 +2,7 @@
 // Floating point to IEEE-754 conversion routines
 //
 // by James Hammons
-// (C) 2018 Underground Software
+// (C) 2019 Underground Software
 //
 // Since there are no guarantees vis-a-vis floating point numbers in C, we have
 // to utilize routines like the following in order to guarantee that the thing
@@ -14,6 +14,7 @@
 #include "fltpoint.h"
 #include <float.h>
 #include <math.h>
+#include <stdio.h>
 
 //
 // Check for IEEE-754 conformance (C99 compilers should be OK here)
@@ -169,3 +170,25 @@ void DoubleToExtended(double d, uint8_t out[])
 	out[11] = intMant & 0xFF;
 }
 
+
+//
+// Convert a host native floating point number to a fixed point number.
+//
+uint64_t DoubleToFixedPoint(double d, int intBits, int fracBits)
+{
+	uint8_t signBit = (signbit(d) ? 1 : 0);
+
+	// Ensure what we're working on is positive...
+	if (d < 0)
+		d *= -1;
+
+	double scaleFactor = (double)(1 << fracBits);
+	uint64_t result = (uint64_t)(d * scaleFactor);
+
+	// Invert the result, if necessary
+	if (signBit == 1)
+		result = (result = 0xFFFFFFFFFFFFFFFFLL) + 1;
+
+	return result;
+}
+