ext: Include libfputils

This changeset includes libfputils from revision bbf0d61d75. This
library can be used to convert to and from 80-bit floats and query the
type of an 80-bit float, which is needed to support the x87 FPU.

1 files changed, 253 insertions, 0 deletions

diff --git a/ext/fputils/include/fputils/fp80.h b/ext/fputils/include/fputils/fp80.h
new file mode 100644
index 000000000..e584baab4
--- /dev/null
+++ b/ext/fputils/include/fputils/fp80.h
@@ -0,0 +1,253 @@
+/*
+ * Copyright (c) 2013, Andreas Sandberg
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above
+ *    copyright notice, this list of conditions and the following
+ *    disclaimer in the documentation and/or other materials provided
+ *    with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _FP80_H
+#define _FP80_H 1
+
+#include <math.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#ifdef  __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @defgroup fp80 80-bit Floats
+ * Functions handling 80-bit floats.
+ *
+ * @{
+ */
+
+/** Internal representation of an 80-bit float. */
+typedef struct  {
+    union {
+        char bits[10];
+        struct {
+            uint64_t fi;
+            uint16_t se;
+        } repr;
+    } u;
+} fp80_t;
+
+/** Constant representing +inf */
+extern const fp80_t fp80_pinf;
+/** Constant representing -inf */
+extern const fp80_t fp80_ninf;
+/** Constant representing a quiet NaN */
+extern const fp80_t fp80_qnan;
+/** Constant representing a quiet indefinite NaN */
+extern const fp80_t fp80_qnani;
+/** Constant representing a signaling NaN */
+extern const fp80_t fp80_snan;
+/** Alias for fp80_qnan */
+extern const fp80_t fp80_nan;
+
+/**
+ * Is the value a special floating point value?
+ *
+ * Determine if a floating point value is one of the special values
+ * (i.e., one of the infinities or NaNs). In practice, this function
+ * only checks if the exponent is set to the maximum value supported
+ * by the binary representation, which is a reserved value used for
+ * such special numbers.
+ *
+ * @param fp80 value to analyze.
+ * @return 1 if the value is special, 0 otherwise.
+ */
+int fp80_isspecial(fp80_t fp80);
+/**
+ * Is the value a quiet NaN?
+ *
+ * @param fp80 value to analyze.
+ * @return 1 if true, 0 otherwise.
+ */
+int fp80_isqnan(fp80_t fp80);
+/**
+ * Is the value an indefinite quiet NaN?
+ *
+ * @param fp80 value to analyze.
+ * @return 1 if true, 0 otherwise.
+ */
+int fp80_isqnani(fp80_t fp80);
+/**
+ * Is the value a signaling NaN?
+ *
+ * @param fp80 value to analyze.
+ * @return 1 if true, 0 otherwise.
+ */
+int fp80_issnan(fp80_t fp80);
+
+/**
+ * Classify a floating point number.
+ *
+ * This function implements the same classification as the standard
+ * fpclassify() function. It returns one of the following floating
+ * point classes:
+ * <ul>
+ *   <li>FP_NAN - The value is NaN.
+ *   <li>FP_INFINITE - The value is either +inf or -inf.
+ *   <li>FP_ZERO - The value is either +0 or -0.
+ *   <li>FP_SUBNORMAL - The value is to small to be represented as a
+ *                      normalized float. See fp80_issubnormal().
+ *   <li>FP_NORMAL - The value is neither of above.
+ * </ul>
+ *
+ * @param fp80 value to analyze.
+ * @return Floating point classification.
+ */
+int fp80_classify(fp80_t fp80);
+
+/**
+ * Is a value finite?
+ *
+ * Check if a value is a finite value. That is, not one of the
+ * infinities or NaNs.
+ *
+ * @param fp80 value to analyze.
+ * @return -1 if negative finite, +1 if positive finite, 0 otherwise.
+ */
+int fp80_isfinite(fp80_t fp80);
+/**
+ * Is the value a non-zero normal?
+ *
+ * This function checks if a floating point value is a normal (having
+ * an exponent larger or equal to 1) or not. See fp80_issubnormal()
+ * for a description of what a denormal value is.
+ *
+ * @see fp80_issubnormal()
+ *
+ * @param fp80 value to analyze.
+ * @return -1 if negative normal, +1 if positive normal, 0 otherwise.
+ */
+int fp80_isnormal(fp80_t fp80);
+/**
+ * Is the value a NaN of any kind?
+ *
+ * @param fp80 value to analyze.
+ * @return -1 if negative NaN, +1 if positive NaN, 0 otherwise.
+ */
+int fp80_isnan(fp80_t fp80);
+/**
+ * Is the value one of the infinities?
+ *
+ * @param fp80 value to analyze.
+ * @return -1 if -inf, +1 if +inf, 0 otherwise.
+ */
+int fp80_isinf(fp80_t fp80);
+/**
+ * Determine value of the sign-bit of a floating point number.
+ *
+ * @note Floats can represent both positive and negative zeros.
+ *
+ * @param fp80 value to analyze.
+ * @return -1 if negative, +1 if positive.
+ */
+int fp80_sgn(fp80_t fp80);
+/**
+ * Is the value zero?
+ *
+ * @param fp80 value to analyze.
+ * @return -1 if negative zero, +1 if positive zero, 0 otherwise.
+ */
+int fp80_iszero(fp80_t fp80);
+/**
+ * Is the value a denormal?
+ *
+ * Numbers that are close to the minimum of what can be stored in a
+ * floating point number start loosing precision because bits in the
+ * fraction get used (implicitly) to store parts of the negative
+ * exponent (i.e., the exponent is saturated and the fraction is less
+ * than 1). Such numbers are known as denormals. This function checks
+ * whether a float is a denormal or not.
+ *
+ * @param fp80 value to analyze.
+ * @return -1 if negative denormal, +1 if positive denormal, 0 otherwise.
+ */
+int fp80_issubnormal(fp80_t fp80);
+
+/**
+ * Convert an 80-bit float to a 64-bit double.
+ *
+ * This function converts an 80-bit float into a standard 64-bit
+ * double. This conversion is inherently lossy since a double can only
+ * represent a subset of what an 80-bit float can represent. The
+ * fraction of the source value will always be truncated to fit the
+ * lower precision. If a value falls outside of the range that can be
+ * accurately represented by double by truncating the fraction, one of
+ * the following happens:
+ * <ul>
+ *   <li>A denormal will be generated if that can approximate the
+ *       value.
+ *   <li>[-]0 will be generated if the magnitude of the value is too
+ *       small to be represented at all.
+ *   <li>+-Inf will be generated if the magnitude of the value is too
+ *       large to be represented.
+ * </ul>
+ *
+ * NaN values will be preserved across the conversion.
+ *
+ * @param fp80 Source value to convert.
+ * @return 64-bit version of the float.
+ */
+double fp80_cvtd(fp80_t fp80);
+
+/**
+ * Convert an 64-bit double to an 80-bit float.
+ *
+ * This function converts a standard 64-bit double into an 80-bit
+ * float. This conversion is completely lossless since the 80-bit
+ * float represents a superset of what a 64-bit double can
+ * represent.
+ *
+ * @note Denormals will be converted to normalized values.
+ *
+ * @param fpd Source value to convert.
+ * @return 64-bit version of the float.
+ */
+fp80_t fp80_cvfd(double fpd);
+
+/**
+ * Dump the components of an 80-bit float to a file.
+ *
+ * @warning This function is intended for debugging and the format of
+ * the output is not guaranteed to be stable.
+ *
+ * @param fout Output stream (e.g., stdout)
+ * @param fp80 value to dump.
+ */
+void fp80_debug_dump(FILE *fout, fp80_t fp80);
+
+/** @} */
+
+#ifdef  __cplusplus
+} /* extern "C" */
+#endif
+
+#endif