add an almost complete libm implementation

again taken from musl.

For now disabled:

 - floor, ceil: we have an asm implementation, but need to check if it's enough
 - various functions that mess with the floating point exception status.

libc/build.mak

@@ -107,6 +107,217 @@ libc += locale/wcsxfrm_l.o
 libc += locale/wctrans_l.o
 libc += locale/wctype_l.o
 
+libc += math/__cos.o
+libc += math/__cosdf.o
+libc += math/__cosl.o
+libc += math/__expo2.o
+libc += math/__expo2f.o
+libc += math/__fpclassify.o
+libc += math/__fpclassifyf.o
+libc += math/__fpclassifyl.o
+libc += math/__invtrigl.o
+libc += math/__polevll.o
+libc += math/__rem_pio2.o
+libc += math/__rem_pio2_large.o
+libc += math/__rem_pio2f.o
+libc += math/__rem_pio2l.o
+libc += math/__signbit.o
+libc += math/__signbitf.o
+libc += math/__signbitl.o
+libc += math/__sin.o
+libc += math/__sindf.o
+libc += math/__sinl.o
+libc += math/__tan.o
+libc += math/__tandf.o
+libc += math/__tanl.o
+libc += math/acos.o
+libc += math/acosf.o
+libc += math/acosh.o
+libc += math/acoshf.o
+libc += math/acoshl.o
+libc += math/acosl.o
+libc += math/asin.o
+libc += math/asinf.o
+libc += math/asinh.o
+libc += math/asinhf.o
+libc += math/asinhl.o
+libc += math/asinl.o
+libc += math/atan.o
+libc += math/atan2.o
+libc += math/atan2f.o
+libc += math/atan2l.o
+libc += math/atanf.o
+libc += math/atanh.o
+libc += math/atanhf.o
+libc += math/atanhl.o
+libc += math/atanl.o
+libc += math/cbrt.o
+libc += math/cbrtf.o
+libc += math/cbrtl.o
+#libc += math/ceil.o
+libc += math/ceilf.o
+libc += math/ceill.o
+libc += math/copysign.o
+libc += math/copysignf.o
+libc += math/copysignl.o
+libc += math/cos.o
+libc += math/cosf.o
+libc += math/cosh.o
+libc += math/coshf.o
+libc += math/coshl.o
+libc += math/cosl.o
+libc += math/erf.o
+libc += math/erff.o
+libc += math/erfl.o
+libc += math/exp.o
+libc += math/exp10.o
+libc += math/exp10f.o
+libc += math/exp10l.o
+libc += math/exp2.o
+libc += math/exp2f.o
+libc += math/exp2l.o
+libc += math/expf.o
+libc += math/expl.o
+libc += math/expm1.o
+libc += math/expm1f.o
+libc += math/expm1l.o
+libc += math/fabs.o
+libc += math/fabsf.o
+libc += math/fabsl.o
+libc += math/fdim.o
+libc += math/fdimf.o
+libc += math/fdiml.o
+#libc += math/floor.o
+libc += math/floorf.o
+libc += math/floorl.o
+#libc += math/fma.o
+#libc += math/fmaf.o
+#libc += math/fmal.o
+libc += math/fmax.o
+libc += math/fmaxf.o
+libc += math/fmaxl.o
+libc += math/fmin.o
+libc += math/fminf.o
+libc += math/fminl.o
+libc += math/fmod.o
+libc += math/fmodf.o
+libc += math/fmodl.o
+libc += math/frexp.o
+libc += math/frexpf.o
+libc += math/frexpl.o
+libc += math/hypot.o
+libc += math/hypotf.o
+libc += math/hypotl.o
+libc += math/ilogb.o
+libc += math/ilogbf.o
+libc += math/ilogbl.o
+libc += math/j0.o
+libc += math/j0f.o
+libc += math/j1.o
+libc += math/j1f.o
+libc += math/jn.o
+libc += math/jnf.o
+libc += math/ldexp.o
+libc += math/ldexpf.o
+libc += math/ldexpl.o
+libc += math/lgamma.o
+libc += math/lgamma_r.o
+libc += math/lgammaf.o
+libc += math/lgammaf_r.o
+libc += math/lgammal.o
+#libc += math/llrint.o
+#libc += math/llrintf.o
+#libc += math/llrintl.o
+libc += math/llround.o
+libc += math/llroundf.o
+libc += math/llroundl.o
+libc += math/log.o
+libc += math/log10.o
+libc += math/log10f.o
+libc += math/log10l.o
+libc += math/log1p.o
+libc += math/log1pf.o
+libc += math/log1pl.o
+libc += math/log2.o
+libc += math/log2f.o
+libc += math/log2l.o
+libc += math/logb.o
+libc += math/logbf.o
+libc += math/logbl.o
+libc += math/logf.o
+libc += math/logl.o
+#libc += math/lrint.o
+#libc += math/lrintf.o
+#libc += math/lrintl.o
+libc += math/lround.o
+libc += math/lroundf.o
+libc += math/lroundl.o
+libc += math/modf.o
+libc += math/modff.o
+libc += math/modfl.o
+libc += math/nan.o
+libc += math/nanf.o
+libc += math/nanl.o
+#libc += math/nearbyint.o
+#libc += math/nearbyintf.o
+#libc += math/nearbyintl.o
+libc += math/nextafter.o
+libc += math/nextafterf.o
+libc += math/nextafterl.o
+libc += math/nexttoward.o
+libc += math/nexttowardf.o
+libc += math/nexttowardl.o
+libc += math/pow.o
+libc += math/powf.o
+libc += math/powl.o
+libc += math/remainder.o
+libc += math/remainderf.o
+libc += math/remainderl.o
+libc += math/remquo.o
+libc += math/remquof.o
+libc += math/remquol.o
+libc += math/rint.o
+libc += math/rintf.o
+libc += math/rintl.o
+libc += math/round.o
+libc += math/roundf.o
+libc += math/roundl.o
+libc += math/scalb.o
+libc += math/scalbf.o
+libc += math/scalbln.o
+libc += math/scalblnf.o
+libc += math/scalblnl.o
+libc += math/scalbn.o
+libc += math/scalbnf.o
+libc += math/scalbnl.o
+libc += math/signgam.o
+libc += math/significand.o
+libc += math/significandf.o
+libc += math/sin.o
+libc += math/sincos.o
+libc += math/sincosf.o
+libc += math/sincosl.o
+libc += math/sinf.o
+libc += math/sinh.o
+libc += math/sinhf.o
+libc += math/sinhl.o
+libc += math/sinl.o
+libc += math/sqrt.o
+libc += math/sqrtf.o
+libc += math/sqrtl.o
+libc += math/tan.o
+libc += math/tanf.o
+libc += math/tanh.o
+libc += math/tanhf.o
+libc += math/tanhl.o
+libc += math/tanl.o
+libc += math/tgamma.o
+libc += math/tgammaf.o
+libc += math/tgammal.o
+libc += math/trunc.o
+libc += math/truncf.o
+libc += math/truncl.o
+
 libc += misc/a64l.o
 libc += misc/basename.o
 libc += misc/dirname.o

libc/internal/libm.h

@@ -0,0 +1,176 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/math_private.h */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+#ifndef _LIBM_H
+#define _LIBM_H
+
+#include <stdint.h>
+#include <float.h>
+#include "math.h"
+#include <complex.h>
+
+#include "longdbl.h"
+
+#include "libc.h"
+
+union fshape {
+	float value;
+	uint32_t bits;
+};
+
+union dshape {
+	double value;
+	uint64_t bits;
+};
+
+#define FORCE_EVAL(x) do {                          \
+	if (sizeof(x) == sizeof(float)) {           \
+		volatile float __x;                 \
+		__x = (x);                          \
+	} else if (sizeof(x) == sizeof(double)) {   \
+		volatile double __x;                \
+		__x = (x);                          \
+	} else {                                    \
+		volatile long double __x;           \
+		__x = (x);                          \
+	}                                           \
+} while(0)
+
+/* Get two 32 bit ints from a double.  */
+#define EXTRACT_WORDS(hi,lo,d)                                  \
+do {                                                            \
+  union dshape __u;                                             \
+  __u.value = (d);                                              \
+  (hi) = __u.bits >> 32;                                        \
+  (lo) = (uint32_t)__u.bits;                                    \
+} while (0)
+
+/* Get a 64 bit int from a double.  */
+#define EXTRACT_WORD64(i,d)                                     \
+do {                                                            \
+  union dshape __u;                                             \
+  __u.value = (d);                                              \
+  (i) = __u.bits;                                               \
+} while (0)
+
+/* Get the more significant 32 bit int from a double.  */
+#define GET_HIGH_WORD(i,d)                                      \
+do {                                                            \
+  union dshape __u;                                             \
+  __u.value = (d);                                              \
+  (i) = __u.bits >> 32;                                         \
+} while (0)
+
+/* Get the less significant 32 bit int from a double.  */
+#define GET_LOW_WORD(i,d)                                       \
+do {                                                            \
+  union dshape __u;                                             \
+  __u.value = (d);                                              \
+  (i) = (uint32_t)__u.bits;                                     \
+} while (0)
+
+/* Set a double from two 32 bit ints.  */
+#define INSERT_WORDS(d,hi,lo)                                   \
+do {                                                            \
+  union dshape __u;                                             \
+  __u.bits = ((uint64_t)(hi) << 32) | (uint32_t)(lo);           \
+  (d) = __u.value;                                              \
+} while (0)
+
+/* Set a double from a 64 bit int.  */
+#define INSERT_WORD64(d,i)                                      \
+do {                                                            \
+  union dshape __u;                                             \
+  __u.bits = (i);                                               \
+  (d) = __u.value;                                              \
+} while (0)
+
+/* Set the more significant 32 bits of a double from an int.  */
+#define SET_HIGH_WORD(d,hi)                                     \
+do {                                                            \
+  union dshape __u;                                             \
+  __u.value = (d);                                              \
+  __u.bits &= 0xffffffff;                                       \
+  __u.bits |= (uint64_t)(hi) << 32;                             \
+  (d) = __u.value;                                              \
+} while (0)
+
+/* Set the less significant 32 bits of a double from an int.  */
+#define SET_LOW_WORD(d,lo)                                      \
+do {                                                            \
+  union dshape __u;                                             \
+  __u.value = (d);                                              \
+  __u.bits &= 0xffffffff00000000ull;                            \
+  __u.bits |= (uint32_t)(lo);                                   \
+  (d) = __u.value;                                              \
+} while (0)
+
+/* Get a 32 bit int from a float.  */
+#define GET_FLOAT_WORD(i,d)                                     \
+do {                                                            \
+  union fshape __u;                                             \
+  __u.value = (d);                                              \
+  (i) = __u.bits;                                               \
+} while (0)
+
+/* Set a float from a 32 bit int.  */
+#define SET_FLOAT_WORD(d,i)                                     \
+do {                                                            \
+  union fshape __u;                                             \
+  __u.bits = (i);                                               \
+  (d) = __u.value;                                              \
+} while (0)
+
+/* fdlibm kernel functions */
+
+int    __rem_pio2_large(double*,double*,int,int,int);
+
+int    __rem_pio2(double,double*);
+double __sin(double,double,int);
+double __cos(double,double);
+double __tan(double,double,int);
+double __expo2(double);
+double complex __ldexp_cexp(double complex,int);
+
+int    __rem_pio2f(float,double*);
+float  __sindf(double);
+float  __cosdf(double);
+float  __tandf(double,int);
+float  __expo2f(float);
+float complex __ldexp_cexpf(float complex,int);
+
+int __rem_pio2l(long double, long double *);
+long double __sinl(long double, long double, int);
+long double __cosl(long double, long double);
+long double __tanl(long double, long double, int);
+
+/* polynomial evaluation */
+long double __polevll(long double, const long double *, int);
+long double __p1evll(long double, const long double *, int);
+
+#if 0
+/* Attempt to get strict C99 semantics for assignment with non-C99 compilers. */
+#define STRICT_ASSIGN(type, lval, rval) do {    \
+        volatile type __v = (rval);             \
+        (lval) = __v;                           \
+} while (0)
+#else
+/* Should work with -fexcess-precision=standard (>=gcc-4.5) or -ffloat-store */
+#define STRICT_ASSIGN(type, lval, rval) ((lval) = (type)(rval))
+#endif
+
+/* should be in math.h, which we can't include at the moment */
+double scalbn(double x, int exp);
+int __isnan(double x);
+
+
+#endif