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-rw-r--r--stmhal/math.c407
1 files changed, 407 insertions, 0 deletions
diff --git a/stmhal/math.c b/stmhal/math.c
new file mode 100644
index 0000000000..8e2c6fc753
--- /dev/null
+++ b/stmhal/math.c
@@ -0,0 +1,407 @@
+#include <stdint.h>
+#include <math.h>
+
+// these 2 functions seem to actually work... no idea why
+// replacing with libgcc does not work (probably due to wrong calling conventions)
+double __aeabi_f2d(float x) {
+ // TODO
+ return 0.0;
+}
+
+float __aeabi_d2f(double x) {
+ // TODO
+ return 0.0;
+}
+
+/*
+double sqrt(double x) {
+ // TODO
+ return 0.0;
+}
+*/
+
+float sqrtf(float x) {
+ asm volatile (
+ "vsqrt.f32 %[r], %[x]\n"
+ : [r] "=t" (x)
+ : [x] "t" (x));
+ return x;
+}
+
+// TODO we need import these functions from some library (eg musl or newlib)
+float powf(float x, float y) { return 0.0; }
+float logf(float x) { return 0.0; }
+float log2f(float x) { return 0.0; }
+float log10f(float x) { return 0.0; }
+float tanhf(float x) { return 0.0; }
+float acoshf(float x) { return 0.0; }
+float asinhf(float x) { return 0.0; }
+float atanhf(float x) { return 0.0; }
+float cosf(float x) { return 0.0; }
+float sinf(float x) { return 0.0; }
+float tanf(float x) { return 0.0; }
+float acosf(float x) { return 0.0; }
+float asinf(float x) { return 0.0; }
+float atanf(float x) { return 0.0; }
+float atan2f(float x, float y) { return 0.0; }
+
+/*****************************************************************************/
+// from musl-0.9.15 libm.h
+
+/* 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.
+ * ====================================================
+ */
+
+#define FORCE_EVAL(x) do { \
+ if (sizeof(x) == sizeof(float)) { \
+ volatile float __x; \
+ __x = (x); \
+ (void)__x; \
+ } else if (sizeof(x) == sizeof(double)) { \
+ volatile double __x; \
+ __x = (x); \
+ (void)__x; \
+ } else { \
+ volatile long double __x; \
+ __x = (x); \
+ (void)__x; \
+ } \
+} while(0)
+
+/* Get a 32 bit int from a float. */
+#define GET_FLOAT_WORD(w,d) \
+do { \
+ union {float f; uint32_t i;} __u; \
+ __u.f = (d); \
+ (w) = __u.i; \
+} while (0)
+
+/* Set a float from a 32 bit int. */
+#define SET_FLOAT_WORD(d,w) \
+do { \
+ union {float f; uint32_t i;} __u; \
+ __u.i = (w); \
+ (d) = __u.f; \
+} while (0)
+
+/*****************************************************************************/
+// scalbnf from musl-0.9.15
+
+float scalbnf(float x, int n)
+{
+ union {float f; uint32_t i;} u;
+ float_t y = x;
+
+ if (n > 127) {
+ y *= 0x1p127f;
+ n -= 127;
+ if (n > 127) {
+ y *= 0x1p127f;
+ n -= 127;
+ if (n > 127)
+ n = 127;
+ }
+ } else if (n < -126) {
+ y *= 0x1p-126f;
+ n += 126;
+ if (n < -126) {
+ y *= 0x1p-126f;
+ n += 126;
+ if (n < -126)
+ n = -126;
+ }
+ }
+ u.i = (uint32_t)(0x7f+n)<<23;
+ x = y * u.f;
+ return x;
+}
+
+/*****************************************************************************/
+// expf from musl-0.9.15
+
+/* origin: FreeBSD /usr/src/lib/msun/src/e_expf.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.
+ * ====================================================
+ */
+
+static const float
+half[2] = {0.5,-0.5},
+ln2hi = 6.9314575195e-1f, /* 0x3f317200 */
+ln2lo = 1.4286067653e-6f, /* 0x35bfbe8e */
+invln2 = 1.4426950216e+0f, /* 0x3fb8aa3b */
+/*
+ * Domain [-0.34568, 0.34568], range ~[-4.278e-9, 4.447e-9]:
+ * |x*(exp(x)+1)/(exp(x)-1) - p(x)| < 2**-27.74
+ */
+P1 = 1.6666625440e-1f, /* 0xaaaa8f.0p-26 */
+P2 = -2.7667332906e-3f; /* -0xb55215.0p-32 */
+
+float expf(float x)
+{
+ float_t hi, lo, c, xx, y;
+ int k, sign;
+ uint32_t hx;
+
+ GET_FLOAT_WORD(hx, x);
+ sign = hx >> 31; /* sign bit of x */
+ hx &= 0x7fffffff; /* high word of |x| */
+
+ /* special cases */
+ if (hx >= 0x42aeac50) { /* if |x| >= -87.33655f or NaN */
+ if (hx >= 0x42b17218 && !sign) { /* x >= 88.722839f */
+ /* overflow */
+ x *= 0x1p127f;
+ return x;
+ }
+ if (sign) {
+ /* underflow */
+ FORCE_EVAL(-0x1p-149f/x);
+ if (hx >= 0x42cff1b5) /* x <= -103.972084f */
+ return 0;
+ }
+ }
+
+ /* argument reduction */
+ if (hx > 0x3eb17218) { /* if |x| > 0.5 ln2 */
+ if (hx > 0x3f851592) /* if |x| > 1.5 ln2 */
+ k = invln2*x + half[sign];
+ else
+ k = 1 - sign - sign;
+ hi = x - k*ln2hi; /* k*ln2hi is exact here */
+ lo = k*ln2lo;
+ x = hi - lo;
+ } else if (hx > 0x39000000) { /* |x| > 2**-14 */
+ k = 0;
+ hi = x;
+ lo = 0;
+ } else {
+ /* raise inexact */
+ FORCE_EVAL(0x1p127f + x);
+ return 1 + x;
+ }
+
+ /* x is now in primary range */
+ xx = x*x;
+ c = x - xx*(P1+xx*P2);
+ y = 1 + (x*c/(2-c) - lo + hi);
+ if (k == 0)
+ return y;
+ return scalbnf(y, k);
+}
+
+/*****************************************************************************/
+// expm1f from musl-0.9.15
+
+/* origin: FreeBSD /usr/src/lib/msun/src/s_expm1f.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.
+ * ====================================================
+ */
+
+static const float
+o_threshold = 8.8721679688e+01, /* 0x42b17180 */
+ln2_hi = 6.9313812256e-01, /* 0x3f317180 */
+ln2_lo = 9.0580006145e-06, /* 0x3717f7d1 */
+//invln2 = 1.4426950216e+00, /* 0x3fb8aa3b */
+/*
+ * Domain [-0.34568, 0.34568], range ~[-6.694e-10, 6.696e-10]:
+ * |6 / x * (1 + 2 * (1 / (exp(x) - 1) - 1 / x)) - q(x)| < 2**-30.04
+ * Scaled coefficients: Qn_here = 2**n * Qn_for_q (see s_expm1.c):
+ */
+Q1 = -3.3333212137e-2, /* -0x888868.0p-28 */
+Q2 = 1.5807170421e-3; /* 0xcf3010.0p-33 */
+
+float expm1f(float x)
+{
+ float_t y,hi,lo,c,t,e,hxs,hfx,r1,twopk;
+ union {float f; uint32_t i;} u = {x};
+ uint32_t hx = u.i & 0x7fffffff;
+ int k, sign = u.i >> 31;
+
+ /* filter out huge and non-finite argument */
+ if (hx >= 0x4195b844) { /* if |x|>=27*ln2 */
+ if (hx > 0x7f800000) /* NaN */
+ return x;
+ if (sign)
+ return -1;
+ if (x > o_threshold) {
+ x *= 0x1p127f;
+ return x;
+ }
+ }
+
+ /* argument reduction */
+ if (hx > 0x3eb17218) { /* if |x| > 0.5 ln2 */
+ if (hx < 0x3F851592) { /* and |x| < 1.5 ln2 */
+ if (!sign) {
+ hi = x - ln2_hi;
+ lo = ln2_lo;
+ k = 1;
+ } else {
+ hi = x + ln2_hi;
+ lo = -ln2_lo;
+ k = -1;
+ }
+ } else {
+ k = invln2*x + (sign ? -0.5f : 0.5f);
+ t = k;
+ hi = x - t*ln2_hi; /* t*ln2_hi is exact here */
+ lo = t*ln2_lo;
+ }
+ x = hi-lo;
+ c = (hi-x)-lo;
+ } else if (hx < 0x33000000) { /* when |x|<2**-25, return x */
+ if (hx < 0x00800000)
+ FORCE_EVAL(x*x);
+ return x;
+ } else
+ k = 0;
+
+ /* x is now in primary range */
+ hfx = 0.5f*x;
+ hxs = x*hfx;
+ r1 = 1.0f+hxs*(Q1+hxs*Q2);
+ t = 3.0f - r1*hfx;
+ e = hxs*((r1-t)/(6.0f - x*t));
+ if (k == 0) /* c is 0 */
+ return x - (x*e-hxs);
+ e = x*(e-c) - c;
+ e -= hxs;
+ /* exp(x) ~ 2^k (x_reduced - e + 1) */
+ if (k == -1)
+ return 0.5f*(x-e) - 0.5f;
+ if (k == 1) {
+ if (x < -0.25f)
+ return -2.0f*(e-(x+0.5f));
+ return 1.0f + 2.0f*(x-e);
+ }
+ u.i = (0x7f+k)<<23; /* 2^k */
+ twopk = u.f;
+ if (k < 0 || k > 56) { /* suffice to return exp(x)-1 */
+ y = x - e + 1.0f;
+ if (k == 128)
+ y = y*2.0f*0x1p127f;
+ else
+ y = y*twopk;
+ return y - 1.0f;
+ }
+ u.i = (0x7f-k)<<23; /* 2^-k */
+ if (k < 23)
+ y = (x-e+(1-u.f))*twopk;
+ else
+ y = (x-(e+u.f)+1)*twopk;
+ return y;
+}
+
+/*****************************************************************************/
+// __expo2f from musl-0.9.15
+
+/* k is such that k*ln2 has minimal relative error and x - kln2 > log(FLT_MIN) */
+static const int k = 235;
+static const float kln2 = 0x1.45c778p+7f;
+
+/* expf(x)/2 for x >= log(FLT_MAX), slightly better than 0.5f*expf(x/2)*expf(x/2) */
+float __expo2f(float x)
+{
+ float scale;
+
+ /* note that k is odd and scale*scale overflows */
+ SET_FLOAT_WORD(scale, (uint32_t)(0x7f + k/2) << 23);
+ /* exp(x - k ln2) * 2**(k-1) */
+ return expf(x - kln2) * scale * scale;
+}
+
+/*****************************************************************************/
+// coshf from musl-0.9.15
+
+float coshf(float x)
+{
+ union {float f; uint32_t i;} u = {.f = x};
+ uint32_t w;
+ float t;
+
+ /* |x| */
+ u.i &= 0x7fffffff;
+ x = u.f;
+ w = u.i;
+
+ /* |x| < log(2) */
+ if (w < 0x3f317217) {
+ if (w < 0x3f800000 - (12<<23)) {
+ FORCE_EVAL(x + 0x1p120f);
+ return 1;
+ }
+ t = expm1f(x);
+ return 1 + t*t/(2*(1+t));
+ }
+
+ /* |x| < log(FLT_MAX) */
+ if (w < 0x42b17217) {
+ t = expf(x);
+ return 0.5f*(t + 1/t);
+ }
+
+ /* |x| > log(FLT_MAX) or nan */
+ t = __expo2f(x);
+ return t;
+}
+
+/*****************************************************************************/
+// sinhf from musl-0.9.15
+
+float sinhf(float x)
+{
+ union {float f; uint32_t i;} u = {.f = x};
+ uint32_t w;
+ float t, h, absx;
+
+ h = 0.5;
+ if (u.i >> 31)
+ h = -h;
+ /* |x| */
+ u.i &= 0x7fffffff;
+ absx = u.f;
+ w = u.i;
+
+ /* |x| < log(FLT_MAX) */
+ if (w < 0x42b17217) {
+ t = expm1f(absx);
+ if (w < 0x3f800000) {
+ if (w < 0x3f800000 - (12<<23))
+ return x;
+ return h*(2*t - t*t/(t+1));
+ }
+ return h*(t + t/(t+1));
+ }
+
+ /* |x| > logf(FLT_MAX) or nan */
+ t = 2*h*__expo2f(absx);
+ return t;
+}
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