All numerical values are represented in 22:10 fixed point.

svn path=/trunk/libcss/; revision=5762

1 files changed, 45 insertions, 0 deletions

diff --git a/src/utils/fpmath.h b/src/utils/fpmath.h
new file mode 100644
index 0000000..edf6471
--- /dev/null
+++ b/src/utils/fpmath.h
@@ -0,0 +1,45 @@
+/*
+ * This file is part of LibCSS.
+ * Licensed under the MIT License,
+ *                http://www.opensource.org/licenses/mit-license.php
+ * Copyright 2008 John-Mark Bell <jmb@netsurf-browser.org>
+ */
+
+#ifndef css_utils_fpmath_h_
+#define css_utils_fpmath_h_
+
+#include <stdint.h>
+
+/* 22:10 fixed point math */
+typedef int32_t fixed;
+
+/* Add two fixed point values */
+#define FADD(a, b) ((a) + (b))
+/* Subtract two fixed point values */
+#define FSUB(a, b) ((a) - (b))
+/* Multiply two fixed point values */
+#define FMUL(a, b) (((a) * (b)) >> 10)
+/* Divide two fixed point values */
+#define FDIV(a, b) (((a) << 10) / (b))
+
+/* Add an integer to a fixed point value */
+#define FADDI(a, b) ((a) + ((b) << 10))
+/* Subtract an integer from a fixed point value */
+#define FSUBI(a, b) ((a) - ((b) << 10))
+/* Multiply a fixed point value by an integer */
+#define FMULI(a, b) ((a) * (b))
+/* Divide a fixed point value by an integer */
+#define FDIVI(a, b) ((a) / (b))
+
+/* Convert a floating point value to fixed point */
+#define FLTTOFIX(a) ((fixed) ((a) * (float) (1 << 10)))
+/* Convert a fixed point value to floating point */
+#define FIXTOFLT(a) ((float) (a) / (float) (1 << 10))
+
+/* Convert an integer to a fixed point value */
+#define INTTOFIX(a) ((a) << 10)
+/* Convert a fixed point value to an integer */
+#define FIXTOINT(a) ((a) >> 10)
+
+#endif
+