import from github

tools/aif2pcm/extended.c

@@ -0,0 +1,172 @@
+/*	$Id: extended.c,v 1.8 2006/12/23 11:17:49 toad32767 Exp $ */
+/*-
+ * Copyright (c) 2005, 2006 by Marco Trillo <marcotrillo@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any
+ * person obtaining a copy of this software and associated
+ * documentation files (the "Software"), to deal in the
+ * Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice
+ * shall be included in all copies or substantial portions of
+ * the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+ * KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+ * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+ * PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
+ * OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <math.h>
+#include <string.h>
+#include <stdint.h>
+
+/*
+ * Infinite & NAN values
+ * for non-IEEE systems
+ */
+#ifndef HUGE_VAL
+#ifdef HUGE
+#define INFINITE_VALUE	HUGE
+#define NAN_VALUE	HUGE
+#endif
+#else
+#define INFINITE_VALUE	HUGE_VAL
+#define NAN_VALUE	HUGE_VAL
+#endif
+
+/*
+ * IEEE 754 Extended Precision
+ *
+ * Implementation here is the 80-bit extended precision
+ * format of Motorola 68881, Motorola 68882 and Motorola
+ * 68040 FPUs, as well as Intel 80x87 FPUs.
+ *
+ * See:
+ *    http://www.freescale.com/files/32bit/doc/fact_sheet/BR509.pdf
+ */
+/*
+ * Exponent range: [-16383,16383]
+ * Precision for mantissa: 64 bits with no hidden bit
+ * Bias: 16383
+ */
+
+/*
+ * Write IEEE Extended Precision Numbers
+ */
+void
+ieee754_write_extended(double in, uint8_t* out)
+{
+	int sgn, exp, shift;
+	double fraction, t;
+	unsigned int lexp, hexp;
+	unsigned long low, high;
+
+	if (in == 0.0) {
+		memset(out, 0, 10);
+		return;
+	}
+	if (in < 0.0) {
+		in = fabs(in);
+		sgn = 1;
+	} else
+		sgn = 0;
+
+	fraction = frexp(in, &exp);
+
+	if (exp == 0 || exp > 16384) {
+		if (exp > 16384) /* infinite value */
+			low = high = 0;
+		else {
+			low = 0x80000000;
+			high = 0;
+		}
+		exp = 32767;
+		goto done;
+	}
+	fraction = ldexp(fraction, 32);
+	t = floor(fraction);
+	low = (unsigned long) t;
+	fraction -= t;
+	t = floor(ldexp(fraction, 32));
+	high = (unsigned long) t;
+
+	/* Convert exponents < -16382 to -16382 (then they will be
+	 * stored as -16383) */
+	if (exp < -16382) {
+		shift = 0 - exp - 16382;
+		high >>= shift;
+		high |= (low << (32 - shift));
+		low >>= shift;
+		exp = -16382;
+	}
+	exp += 16383 - 1;	/* bias */
+
+done:
+	lexp = ((unsigned int) exp) >> 8;
+	hexp = ((unsigned int) exp) & 0xFF;
+
+	/* big endian */
+	out[0] = ((uint8_t) sgn) << 7;
+	out[0] |= (uint8_t) lexp;
+	out[1] = (uint8_t) hexp;
+	out[2] = (uint8_t) (low >> 24);
+	out[3] = (uint8_t) ((low >> 16) & 0xFF);
+	out[4] = (uint8_t) ((low >> 8) & 0xFF);
+	out[5] = (uint8_t) (low & 0xFF);
+	out[6] = (uint8_t) (high >> 24);
+	out[7] = (uint8_t) ((high >> 16) & 0xFF);
+	out[8] = (uint8_t) ((high >> 8) & 0xFF);
+	out[9] = (uint8_t) (high & 0xFF);
+
+	return;
+}
+
+
+/*
+ * Read IEEE Extended Precision Numbers
+ */
+double
+ieee754_read_extended(uint8_t* in)
+{
+	int sgn, exp;
+	unsigned long low, high;
+	double out;
+
+	/* Extract the components from the big endian buffer */
+	sgn = (int) (in[0] >> 7);
+	exp = ((int) (in[0] & 0x7F) << 8) | ((int) in[1]);
+	low = (((unsigned long) in[2]) << 24)
+		| (((unsigned long) in[3]) << 16)
+		| (((unsigned long) in[4]) << 8) | (unsigned long) in[5];
+	high = (((unsigned long) in[6]) << 24)
+		| (((unsigned long) in[7]) << 16)
+		| (((unsigned long) in[8]) << 8) | (unsigned long) in[9];
+
+	if (exp == 0 && low == 0 && high == 0)
+		return (sgn ? -0.0 : 0.0);
+
+	switch (exp) {
+	case 32767:
+		if (low == 0 && high == 0)
+			return (sgn ? -INFINITE_VALUE : INFINITE_VALUE);
+		else
+			return (sgn ? -NAN_VALUE : NAN_VALUE);
+	default:
+		exp -= 16383;	/* unbias exponent */
+
+	}
+
+	out = ldexp((double) low, -31 + exp);
+	out += ldexp((double) high, -63 + exp);
+
+	return (sgn ? -out : out);
+}