--- /dev/null
+/* -----------------------------------------------------------------------------
+ *
+ * (c) The GHC Team, 1998-2000
+ *
+ * Miscellaneous support for floating-point primitives
+ *
+ * ---------------------------------------------------------------------------*/
+
+#include "PosixSource.h"
+#include "Rts.h"
+
+#include <math.h>
+
+/*
+ * Encoding and decoding Doubles. Code based on the HBC code
+ * (lib/fltcode.c).
+ */
+
+#ifdef _SHORT_LIMB
+#define SIZEOF_LIMB_T SIZEOF_UNSIGNED_INT
+#else
+#ifdef _LONG_LONG_LIMB
+#define SIZEOF_LIMB_T SIZEOF_UNSIGNED_LONG_LONG
+#else
+#define SIZEOF_LIMB_T SIZEOF_UNSIGNED_LONG
+#endif
+#endif
+
+#if SIZEOF_LIMB_T == 4
+#define GMP_BASE 4294967296.0
+#elif SIZEOF_LIMB_T == 8
+#define GMP_BASE 18446744073709551616.0
+#else
+#error Cannot cope with SIZEOF_LIMB_T -- please add definition of GMP_BASE
+#endif
+
+#define DNBIGIT ((SIZEOF_DOUBLE+SIZEOF_LIMB_T-1)/SIZEOF_LIMB_T)
+#define FNBIGIT ((SIZEOF_FLOAT +SIZEOF_LIMB_T-1)/SIZEOF_LIMB_T)
+
+#if IEEE_FLOATING_POINT
+#define MY_DMINEXP ((DBL_MIN_EXP) - (DBL_MANT_DIG) - 1)
+/* DMINEXP is defined in values.h on Linux (for example) */
+#define DHIGHBIT 0x00100000
+#define DMSBIT 0x80000000
+
+#define MY_FMINEXP ((FLT_MIN_EXP) - (FLT_MANT_DIG) - 1)
+#define FHIGHBIT 0x00800000
+#define FMSBIT 0x80000000
+#endif
+
+#ifdef WORDS_BIGENDIAN
+#define L 1
+#define H 0
+#else
+#define L 0
+#define H 1
+#endif
+
+#define __abs(a) (( (a) >= 0 ) ? (a) : (-(a)))
+
+StgDouble
+__encodeDouble (I_ size, StgByteArray ba, I_ e) /* result = s * 2^e */
+{
+ StgDouble r;
+ const mp_limb_t *const arr = (const mp_limb_t *)ba;
+ I_ i;
+
+ /* Convert MP_INT to a double; knows a lot about internal rep! */
+ for(r = 0.0, i = __abs(size)-1; i >= 0; i--)
+ r = (r * GMP_BASE) + arr[i];
+
+ /* Now raise to the exponent */
+ if ( r != 0.0 ) /* Lennart suggests this avoids a bug in MIPS's ldexp */
+ r = ldexp(r, e);
+
+ /* sign is encoded in the size */
+ if (size < 0)
+ r = -r;
+
+ return r;
+}
+
+/* Special version for small Integers */
+StgDouble
+__int_encodeDouble (I_ j, I_ e)
+{
+ StgDouble r;
+
+ r = (StgDouble)__abs(j);
+
+ /* Now raise to the exponent */
+ if ( r != 0.0 ) /* Lennart suggests this avoids a bug in MIPS's ldexp */
+ r = ldexp(r, e);
+
+ /* sign is encoded in the size */
+ if (j < 0)
+ r = -r;
+
+ return r;
+}
+
+StgFloat
+__encodeFloat (I_ size, StgByteArray ba, I_ e) /* result = s * 2^e */
+{
+ StgFloat r;
+ const mp_limb_t *arr = (const mp_limb_t *)ba;
+ I_ i;
+
+ /* Convert MP_INT to a float; knows a lot about internal rep! */
+ for(r = 0.0, i = __abs(size)-1; i >= 0; i--)
+ r = (r * GMP_BASE) + arr[i];
+
+ /* Now raise to the exponent */
+ if ( r != 0.0 ) /* Lennart suggests this avoids a bug in MIPS's ldexp */
+ r = ldexp(r, e);
+
+ /* sign is encoded in the size */
+ if (size < 0)
+ r = -r;
+
+ return r;
+}
+
+/* Special version for small Integers */
+StgFloat
+__int_encodeFloat (I_ j, I_ e)
+{
+ StgFloat r;
+
+ r = (StgFloat)__abs(j);
+
+ /* Now raise to the exponent */
+ if ( r != 0.0 ) /* Lennart suggests this avoids a bug in MIPS's ldexp */
+ r = ldexp(r, e);
+
+ /* sign is encoded in the size */
+ if (j < 0)
+ r = -r;
+
+ return r;
+}
+
+/* This only supports IEEE floating point */
+
+void
+__decodeDouble (MP_INT *man, I_ *exp, StgDouble dbl)
+{
+ /* Do some bit fiddling on IEEE */
+ unsigned int low, high; /* assuming 32 bit ints */
+ int sign, iexp;
+ union { double d; unsigned int i[2]; } u; /* assuming 32 bit ints, 64 bit double */
+
+ ASSERT(sizeof(unsigned int ) == 4 );
+ ASSERT(sizeof(dbl ) == SIZEOF_DOUBLE);
+ ASSERT(sizeof(man->_mp_d[0]) == SIZEOF_LIMB_T);
+ ASSERT(DNBIGIT*SIZEOF_LIMB_T >= SIZEOF_DOUBLE);
+
+ u.d = dbl; /* grab chunks of the double */
+ low = u.i[L];
+ high = u.i[H];
+
+ /* we know the MP_INT* passed in has size zero, so we realloc
+ no matter what.
+ */
+ man->_mp_alloc = DNBIGIT;
+
+ if (low == 0 && (high & ~DMSBIT) == 0) {
+ man->_mp_size = 0;
+ *exp = 0L;
+ } else {
+ man->_mp_size = DNBIGIT;
+ iexp = ((high >> 20) & 0x7ff) + MY_DMINEXP;
+ sign = high;
+
+ high &= DHIGHBIT-1;
+ if (iexp != MY_DMINEXP) /* don't add hidden bit to denorms */
+ high |= DHIGHBIT;
+ else {
+ iexp++;
+ /* A denorm, normalize the mantissa */
+ while (! (high & DHIGHBIT)) {
+ high <<= 1;
+ if (low & DMSBIT)
+ high++;
+ low <<= 1;
+ iexp--;
+ }
+ }
+ *exp = (I_) iexp;
+#if DNBIGIT == 2
+ man->_mp_d[0] = (mp_limb_t)low;
+ man->_mp_d[1] = (mp_limb_t)high;
+#else
+#if DNBIGIT == 1
+ man->_mp_d[0] = ((mp_limb_t)high) << 32 | (mp_limb_t)low;
+#else
+#error Cannot cope with DNBIGIT
+#endif
+#endif
+ if (sign < 0)
+ man->_mp_size = -man->_mp_size;
+ }
+}
+
+void
+__decodeFloat (MP_INT *man, I_ *exp, StgFloat flt)
+{
+ /* Do some bit fiddling on IEEE */
+ int high, sign; /* assuming 32 bit ints */
+ union { float f; int i; } u; /* assuming 32 bit float and int */
+
+ ASSERT(sizeof(int ) == 4 );
+ ASSERT(sizeof(flt ) == SIZEOF_FLOAT );
+ ASSERT(sizeof(man->_mp_d[0]) == SIZEOF_LIMB_T);
+ ASSERT(FNBIGIT*SIZEOF_LIMB_T >= SIZEOF_FLOAT );
+
+ u.f = flt; /* grab the float */
+ high = u.i;
+
+ /* we know the MP_INT* passed in has size zero, so we realloc
+ no matter what.
+ */
+ man->_mp_alloc = FNBIGIT;
+
+ if ((high & ~FMSBIT) == 0) {
+ man->_mp_size = 0;
+ *exp = 0;
+ } else {
+ man->_mp_size = FNBIGIT;
+ *exp = ((high >> 23) & 0xff) + MY_FMINEXP;
+ sign = high;
+
+ high &= FHIGHBIT-1;
+ if (*exp != MY_FMINEXP) /* don't add hidden bit to denorms */
+ high |= FHIGHBIT;
+ else {
+ (*exp)++;
+ /* A denorm, normalize the mantissa */
+ while (! (high & FHIGHBIT)) {
+ high <<= 1;
+ (*exp)--;
+ }
+ }
+#if FNBIGIT == 1
+ man->_mp_d[0] = (mp_limb_t)high;
+#else
+#error Cannot cope with FNBIGIT
+#endif
+ if (sign < 0)
+ man->_mp_size = -man->_mp_size;
+ }
+}
+
+/* Convenient union types for checking the layout of IEEE 754 types -
+ based on defs in GNU libc <ieee754.h>
+*/
+
+union stg_ieee754_flt
+{
+ float f;
+ struct {
+
+#if WORDS_BIGENDIAN
+ unsigned int negative:1;
+ unsigned int exponent:8;
+ unsigned int mantissa:23;
+#else
+ unsigned int mantissa:23;
+ unsigned int exponent:8;
+ unsigned int negative:1;
+#endif
+ } ieee;
+ struct {
+
+#if WORDS_BIGENDIAN
+ unsigned int negative:1;
+ unsigned int exponent:8;
+ unsigned int quiet_nan:1;
+ unsigned int mantissa:22;
+#else
+ unsigned int mantissa:22;
+ unsigned int quiet_nan:1;
+ unsigned int exponent:8;
+ unsigned int negative:1;
+#endif
+ } ieee_nan;
+};
+
+/*
+
+ To recap, here's the representation of a double precision
+ IEEE floating point number:
+
+ sign 63 sign bit (0==positive, 1==negative)
+ exponent 62-52 exponent (biased by 1023)
+ fraction 51-0 fraction (bits to right of binary point)
+*/
+
+union stg_ieee754_dbl
+{
+ double d;
+ struct {
+
+#if WORDS_BIGENDIAN
+ unsigned int negative:1;
+ unsigned int exponent:11;
+ unsigned int mantissa0:20;
+ unsigned int mantissa1:32;
+#else
+ unsigned int mantissa1:32;
+ unsigned int mantissa0:20;
+ unsigned int exponent:11;
+ unsigned int negative:1;
+#endif
+ } ieee;
+ /* This format makes it easier to see if a NaN is a signalling NaN. */
+ struct {
+
+#if WORDS_BIGENDIAN
+ unsigned int negative:1;
+ unsigned int exponent:11;
+ unsigned int quiet_nan:1;
+ unsigned int mantissa0:19;
+ unsigned int mantissa1:32;
+#else
+ unsigned int mantissa1:32;
+ unsigned int mantissa0:19;
+ unsigned int quiet_nan:1;
+ unsigned int exponent:11;
+ unsigned int negative:1;
+#endif
+ } ieee_nan;
+};
+
+/*
+ * Predicates for testing for extreme IEEE fp values. Used
+ * by the bytecode evaluator and the Prelude.
+ *
+ */
+
+/* In case you don't suppport IEEE, you'll just get dummy defs.. */
+#ifdef IEEE_FLOATING_POINT
+
+StgInt
+isDoubleNaN(StgDouble d)
+{
+ union stg_ieee754_dbl u;
+
+ u.d = d;
+
+ return (
+ u.ieee.exponent == 2047 /* 2^11 - 1 */ && /* Is the exponent all ones? */
+ (u.ieee.mantissa0 != 0 || u.ieee.mantissa1 != 0)
+ /* and the mantissa non-zero? */
+ );
+}
+
+StgInt
+isDoubleInfinite(StgDouble d)
+{
+ union stg_ieee754_dbl u;
+
+ u.d = d;
+
+ /* Inf iff exponent is all ones, mantissa all zeros */
+ return (
+ u.ieee.exponent == 2047 /* 2^11 - 1 */ &&
+ u.ieee.mantissa0 == 0 &&
+ u.ieee.mantissa1 == 0
+ );
+}
+
+StgInt
+isDoubleDenormalized(StgDouble d)
+{
+ union stg_ieee754_dbl u;
+
+ u.d = d;
+
+ /* A (single/double/quad) precision floating point number
+ is denormalised iff:
+ - exponent is zero
+ - mantissa is non-zero.
+ - (don't care about setting of sign bit.)
+
+ */
+ return (
+ u.ieee.exponent == 0 &&
+ (u.ieee.mantissa0 != 0 ||
+ u.ieee.mantissa1 != 0)
+ );
+
+}
+
+StgInt
+isDoubleNegativeZero(StgDouble d)
+{
+ union stg_ieee754_dbl u;
+
+ u.d = d;
+ /* sign (bit 63) set (only) => negative zero */
+
+ return (
+ u.ieee.negative == 1 &&
+ u.ieee.exponent == 0 &&
+ u.ieee.mantissa0 == 0 &&
+ u.ieee.mantissa1 == 0);
+}
+
+/* Same tests, this time for StgFloats. */
+
+/*
+ To recap, here's the representation of a single precision
+ IEEE floating point number:
+
+ sign 31 sign bit (0 == positive, 1 == negative)
+ exponent 30-23 exponent (biased by 127)
+ fraction 22-0 fraction (bits to right of binary point)
+*/
+
+
+StgInt
+isFloatNaN(StgFloat f)
+{
+ union stg_ieee754_flt u;
+ u.f = f;
+
+ /* Floating point NaN iff exponent is all ones, mantissa is
+ non-zero (but see below.) */
+ return (
+ u.ieee.exponent == 255 /* 2^8 - 1 */ &&
+ u.ieee.mantissa != 0);
+}
+
+StgInt
+isFloatInfinite(StgFloat f)
+{
+ union stg_ieee754_flt u;
+ u.f = f;
+
+ /* A float is Inf iff exponent is max (all ones),
+ and mantissa is min(all zeros.) */
+ return (
+ u.ieee.exponent == 255 /* 2^8 - 1 */ &&
+ u.ieee.mantissa == 0);
+}
+
+StgInt
+isFloatDenormalized(StgFloat f)
+{
+ union stg_ieee754_flt u;
+ u.f = f;
+
+ /* A (single/double/quad) precision floating point number
+ is denormalised iff:
+ - exponent is zero
+ - mantissa is non-zero.
+ - (don't care about setting of sign bit.)
+
+ */
+ return (
+ u.ieee.exponent == 0 &&
+ u.ieee.mantissa != 0);
+}
+
+StgInt
+isFloatNegativeZero(StgFloat f)
+{
+ union stg_ieee754_flt u;
+ u.f = f;
+
+ /* sign (bit 31) set (only) => negative zero */
+ return (
+ u.ieee.negative &&
+ u.ieee.exponent == 0 &&
+ u.ieee.mantissa == 0);
+}
+
+#else /* ! IEEE_FLOATING_POINT */
+
+/* Dummy definitions of predicates - they all return false */
+StgInt isDoubleNaN(d) StgDouble d; { return 0; }
+StgInt isDoubleInfinite(d) StgDouble d; { return 0; }
+StgInt isDoubleDenormalized(d) StgDouble d; { return 0; }
+StgInt isDoubleNegativeZero(d) StgDouble d; { return 0; }
+StgInt isFloatNaN(f) StgFloat f; { return 0; }
+StgInt isFloatInfinite(f) StgFloat f; { return 0; }
+StgInt isFloatDenormalized(f) StgFloat f; { return 0; }
+StgInt isFloatNegativeZero(f) StgFloat f; { return 0; }
+
+#endif /* ! IEEE_FLOATING_POINT */
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