msvcrt: Import log2f implementation from musl.
Signed-off-by: Piotr Caban <piotr@codeweavers.com> Signed-off-by: Alexandre Julliard <julliard@winehq.org>
This commit is contained in:
Piotr Caban
Alexandre Julliard
parent
b29096cce1
commit
301bde60d3
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@ -19623,7 +19623,6 @@ for ac_func in \
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lgamma \
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lgammaf \
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log2 \
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log2f \
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tgamma \
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tgammaf
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@ -2662,7 +2662,6 @@ AC_CHECK_FUNCS(\
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lgamma \
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lgammaf \
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log2 \
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log2f \
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tgamma \
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tgammaf
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)
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@ -7176,12 +7176,89 @@ double CDECL log2(double x)
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/*********************************************************************
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* log2f (MSVCR120.@)
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*
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* Copied from musl: src/math/log2f.c
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*/
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float CDECL log2f(float x)
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{
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if (x < 0) *_errno() = EDOM;
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else if (x == 0) *_errno() = ERANGE;
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return unix_funcs->log2f( x );
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static const double A[] = {
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-0x1.712b6f70a7e4dp-2,
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0x1.ecabf496832ep-2,
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-0x1.715479ffae3dep-1,
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0x1.715475f35c8b8p0
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};
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static const struct {
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double invc, logc;
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} T[] = {
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{ 0x1.661ec79f8f3bep+0, -0x1.efec65b963019p-2 },
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{ 0x1.571ed4aaf883dp+0, -0x1.b0b6832d4fca4p-2 },
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{ 0x1.49539f0f010bp+0, -0x1.7418b0a1fb77bp-2 },
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{ 0x1.3c995b0b80385p+0, -0x1.39de91a6dcf7bp-2 },
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{ 0x1.30d190c8864a5p+0, -0x1.01d9bf3f2b631p-2 },
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{ 0x1.25e227b0b8eap+0, -0x1.97c1d1b3b7afp-3 },
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{ 0x1.1bb4a4a1a343fp+0, -0x1.2f9e393af3c9fp-3 },
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{ 0x1.12358f08ae5bap+0, -0x1.960cbbf788d5cp-4 },
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{ 0x1.0953f419900a7p+0, -0x1.a6f9db6475fcep-5 },
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{ 0x1p+0, 0x0p+0 },
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{ 0x1.e608cfd9a47acp-1, 0x1.338ca9f24f53dp-4 },
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{ 0x1.ca4b31f026aap-1, 0x1.476a9543891bap-3 },
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{ 0x1.b2036576afce6p-1, 0x1.e840b4ac4e4d2p-3 },
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{ 0x1.9c2d163a1aa2dp-1, 0x1.40645f0c6651cp-2 },
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{ 0x1.886e6037841edp-1, 0x1.88e9c2c1b9ff8p-2 },
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{ 0x1.767dcf5534862p-1, 0x1.ce0a44eb17bccp-2 }
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};
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double z, r, r2, p, y, y0, invc, logc;
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UINT32 ix, iz, top, tmp;
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int k, i;
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ix = *(UINT32*)&x;
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/* Fix sign of zero with downward rounding when x==1. */
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if (ix == 0x3f800000)
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return 0;
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if (ix - 0x00800000 >= 0x7f800000 - 0x00800000) {
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/* x < 0x1p-126 or inf or nan. */
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if (ix * 2 == 0) {
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*_errno() = ERANGE;
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return -1.0f / x;
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}
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if (ix == 0x7f800000) /* log2(inf) == inf. */
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return x;
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if (ix * 2 > 0xff000000)
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return x;
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if (ix & 0x80000000) {
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*_errno() = EDOM;
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return (x - x) / (x - x);
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}
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/* x is subnormal, normalize it. */
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x *= 0x1p23f;
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ix = *(UINT32*)&x;
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ix -= 23 << 23;
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}
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/* x = 2^k z; where z is in range [OFF,2*OFF] and exact.
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The range is split into N subintervals.
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The ith subinterval contains z and c is near its center. */
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tmp = ix - 0x3f330000;
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i = (tmp >> (23 - 4)) % (1 << 4);
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top = tmp & 0xff800000;
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iz = ix - top;
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k = (INT32)tmp >> 23; /* arithmetic shift */
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invc = T[i].invc;
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logc = T[i].logc;
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z = *(float*)&iz;
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/* log2(x) = log1p(z/c-1)/ln2 + log2(c) + k */
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r = z * invc - 1;
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y0 = logc + (double)k;
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/* Pipelined polynomial evaluation to approximate log1p(r)/ln2. */
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r2 = r * r;
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y = A[1] * r + A[2];
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y = A[0] * r2 + y;
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p = A[3] * r + y0;
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y = y * r2 + p;
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return y;
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}
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/*********************************************************************
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@ -132,18 +132,6 @@ static double CDECL unix_log2(double x)
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#endif
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}
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/*********************************************************************
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* log2f
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*/
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static float CDECL unix_log2f(float x)
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{
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#ifdef HAVE_LOG2F
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return log2f(x);
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#else
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return unix_log2(x);
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#endif
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}
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/*********************************************************************
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* pow
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*/
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@ -196,7 +184,6 @@ static const struct unix_funcs funcs =
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unix_lgamma,
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unix_lgammaf,
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unix_log2,
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unix_log2f,
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unix_pow,
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unix_powf,
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unix_tgamma,
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@ -31,7 +31,6 @@ struct unix_funcs
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double (CDECL *lgamma)(double x);
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float (CDECL *lgammaf)(float x);
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double (CDECL *log2)(double x);
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float (CDECL *log2f)(float x);
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double (CDECL *pow)(double x, double y);
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float (CDECL *powf)(float x, float y);
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double (CDECL *tgamma)(double x);
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@ -411,9 +411,6 @@
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/* Define to 1 if you have the `log2' function. */
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#undef HAVE_LOG2
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/* Define to 1 if you have the `log2f' function. */
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#undef HAVE_LOG2F
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/* Define to 1 if you have the `lstat' function. */
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#undef HAVE_LSTAT
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