lib/libm: Add acosh, asinh, atanh, tan; get working with stmhal.

acoshf, asinhf, atanhf were added from musl.  mathsincos.c was
split up into its original, separate files (from newlibe-nano-2).
tan was added.

All of the important missing float functions are now implemented,
and pyboard now passes tests/float/math_fun.py (finally!).

1 files changed, 105 insertions, 0 deletions

diff --git a/lib/libm/kf_tan.c b/lib/libm/kf_tan.c
new file mode 100644
index 0000000000..68254c682c
--- /dev/null
+++ b/lib/libm/kf_tan.c
@@ -0,0 +1,105 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * These math functions are taken from newlib-nano-2, the newlib/libm/math
+ * directory, available from https://github.com/32bitmicro/newlib-nano-2.
+ *
+ * Appropriate copyright headers are reproduced below.
+ */
+
+/* kf_tan.c -- float version of k_tan.c
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ */
+
+#include "libm.h"
+#ifdef __STDC__
+static const float 
+#else
+static float 
+#endif
+one   =  1.0000000000e+00, /* 0x3f800000 */
+pio4  =  7.8539812565e-01, /* 0x3f490fda */
+pio4lo=  3.7748947079e-08, /* 0x33222168 */
+T[] =  {
+  3.3333334327e-01, /* 0x3eaaaaab */
+  1.3333334029e-01, /* 0x3e088889 */
+  5.3968254477e-02, /* 0x3d5d0dd1 */
+  2.1869488060e-02, /* 0x3cb327a4 */
+  8.8632395491e-03, /* 0x3c11371f */
+  3.5920790397e-03, /* 0x3b6b6916 */
+  1.4562094584e-03, /* 0x3abede48 */
+  5.8804126456e-04, /* 0x3a1a26c8 */
+  2.4646313977e-04, /* 0x398137b9 */
+  7.8179444245e-05, /* 0x38a3f445 */
+  7.1407252108e-05, /* 0x3895c07a */
+ -1.8558637748e-05, /* 0xb79bae5f */
+  2.5907305826e-05, /* 0x37d95384 */
+};
+
+#ifdef __STDC__
+	float __kernel_tanf(float x, float y, int iy)
+#else
+	float __kernel_tanf(x, y, iy)
+	float x,y; int iy;
+#endif
+{
+	float z,r,v,w,s;
+	__int32_t ix,hx;
+	GET_FLOAT_WORD(hx,x);
+	ix = hx&0x7fffffff;	/* high word of |x| */
+	if(ix<0x31800000)			/* x < 2**-28 */
+	    {if((int)x==0) {			/* generate inexact */
+		if((ix|(iy+1))==0) return one/fabsf(x);
+		else return (iy==1)? x: -one/x;
+	    }
+	    }
+	if(ix>=0x3f2ca140) { 			/* |x|>=0.6744 */
+	    if(hx<0) {x = -x; y = -y;}
+	    z = pio4-x;
+	    w = pio4lo-y;
+	    x = z+w; y = 0.0;
+	}
+	z	=  x*x;
+	w 	=  z*z;
+    /* Break x^5*(T[1]+x^2*T[2]+...) into
+     *	  x^5(T[1]+x^4*T[3]+...+x^20*T[11]) +
+     *	  x^5(x^2*(T[2]+x^4*T[4]+...+x^22*[T12]))
+     */
+	r = T[1]+w*(T[3]+w*(T[5]+w*(T[7]+w*(T[9]+w*T[11]))));
+	v = z*(T[2]+w*(T[4]+w*(T[6]+w*(T[8]+w*(T[10]+w*T[12])))));
+	s = z*x;
+	r = y + z*(s*(r+v)+y);
+	r += T[0]*s;
+	w = x+r;
+	if(ix>=0x3f2ca140) {
+	    v = (float)iy;
+	    return (float)(1-((hx>>30)&2))*(v-(float)2.0*(x-(w*w/(w+v)-r)));
+	}
+	if(iy==1) return w;
+	else {		/* if allow error up to 2 ulp, 
+			   simply return -1.0/(x+r) here */
+     /*  compute -1.0/(x+r) accurately */
+	    float a,t;
+	    __int32_t i;
+	    z  = w;
+	    GET_FLOAT_WORD(i,z);
+	    SET_FLOAT_WORD(z,i&0xfffff000);
+	    v  = r-(z - x); 	/* z+v = r+x */
+	    t = a  = -(float)1.0/w;	/* a = -1.0/w */
+	    GET_FLOAT_WORD(i,t);
+	    SET_FLOAT_WORD(t,i&0xfffff000);
+	    s  = (float)1.0+t*z;
+	    return t+a*(s+t*v);
+	}
+}