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Diffstat (limited to 'StdLib/Include/sys/ieee754.h')
| -rw-r--r-- | StdLib/Include/sys/ieee754.h | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/StdLib/Include/sys/ieee754.h b/StdLib/Include/sys/ieee754.h new file mode 100644 index 0000000000..740b58eb55 --- /dev/null +++ b/StdLib/Include/sys/ieee754.h @@ -0,0 +1,152 @@ +/* $NetBSD: ieee754.h,v 1.6.24.1 2007/05/07 19:49:10 pavel Exp $ */
+
+/*
+ * Copyright (c) 1992, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This software was developed by the Computer Systems Engineering group
+ * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
+ * contributed to Berkeley.
+ *
+ * All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Lawrence Berkeley Laboratory.
+ *
+ * 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.
+ * 3. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
+ *
+ * @(#)ieee.h 8.1 (Berkeley) 6/11/93
+ */
+#ifndef _SYS_IEEE754_H_
+#define _SYS_IEEE754_H_
+
+/*
+ * NOTICE: This is not a standalone file. To use it, #include it in
+ * your port's ieee.h header.
+ */
+
+#include <machine/endian.h>
+
+/*
+ * <sys/ieee754.h> defines the layout of IEEE 754 floating point types.
+ * Only single-precision and double-precision types are defined here;
+ * extended types, if available, are defined in the machine-dependent
+ * header.
+ */
+
+/*
+ * Define the number of bits in each fraction and exponent.
+ *
+ * k k+1
+ * Note that 1.0 x 2 == 0.1 x 2 and that denorms are represented
+ *
+ * (-exp_bias+1)
+ * as fractions that look like 0.fffff x 2 . This means that
+ *
+ * -126
+ * the number 0.10000 x 2 , for instance, is the same as the normalized
+ *
+ * -127 -128
+ * float 1.0 x 2 . Thus, to represent 2 , we need one leading zero
+ *
+ * -129
+ * in the fraction; to represent 2 , we need two, and so on. This
+ *
+ * (-exp_bias-fracbits+1)
+ * implies that the smallest denormalized number is 2
+ *
+ * for whichever format we are talking about: for single precision, for
+ *
+ * -126 -149
+ * instance, we get .00000000000000000000001 x 2 , or 1.0 x 2 , and
+ *
+ * -149 == -127 - 23 + 1.
+ */
+#define SNG_EXPBITS 8
+#define SNG_FRACBITS 23
+
+struct ieee_single {
+#if _BYTE_ORDER == _BIG_ENDIAN
+ u_int sng_sign:1;
+ u_int sng_exp:SNG_EXPBITS;
+ u_int sng_frac:SNG_FRACBITS;
+#else
+ u_int sng_frac:SNG_FRACBITS;
+ u_int sng_exp:SNG_EXPBITS;
+ u_int sng_sign:1;
+#endif
+};
+
+#define DBL_EXPBITS 11
+#define DBL_FRACHBITS 20
+#define DBL_FRACLBITS 32
+#define DBL_FRACBITS (DBL_FRACHBITS + DBL_FRACLBITS)
+
+struct ieee_double {
+#if _BYTE_ORDER == _BIG_ENDIAN
+ u_int dbl_sign:1;
+ u_int dbl_exp:DBL_EXPBITS;
+ u_int dbl_frach:DBL_FRACHBITS;
+ u_int dbl_fracl:DBL_FRACLBITS;
+#else
+ u_int dbl_fracl:DBL_FRACLBITS;
+ u_int dbl_frach:DBL_FRACHBITS;
+ u_int dbl_exp:DBL_EXPBITS;
+ u_int dbl_sign:1;
+#endif
+};
+
+/*
+ * Floats whose exponent is in [1..INFNAN) (of whatever type) are
+ * `normal'. Floats whose exponent is INFNAN are either Inf or NaN.
+ * Floats whose exponent is zero are either zero (iff all fraction
+ * bits are zero) or subnormal values.
+ *
+ * At least one `signalling NaN' and one `quiet NaN' value must be
+ * implemented. It is left to the architecture to specify how to
+ * distinguish between these.
+ */
+#define SNG_EXP_INFNAN 255
+#define DBL_EXP_INFNAN 2047
+
+/*
+ * Exponent biases.
+ */
+#define SNG_EXP_BIAS 127
+#define DBL_EXP_BIAS 1023
+
+/*
+ * Convenience data structures.
+ */
+union ieee_single_u {
+ float sngu_f;
+ struct ieee_single sngu_sng;
+};
+
+union ieee_double_u {
+ double dblu_d;
+ struct ieee_double dblu_dbl;
+};
+#endif /* _SYS_IEEE754_H_ */
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