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Diffstat (limited to 'tools/aif2pcm/extended.c')
| -rw-r--r-- | tools/aif2pcm/extended.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/tools/aif2pcm/extended.c b/tools/aif2pcm/extended.c new file mode 100644 index 0000000..9444916 --- /dev/null +++ b/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); +} |