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https://github.com/SerenityOS/serenity.git
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LibM: Reimplement some functions using FPU
This commit is contained in:
Egor Ananyin
Andreas Kling
parent
f1b596e75e
commit
92c6ae57fc
1 changed files with 93 additions and 73 deletions
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@ -102,8 +102,12 @@ float sinf(float angle) NOEXCEPT
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double pow(double x, double y) NOEXCEPT
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{
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// FIXME: Please fix me. I am naive.
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if (isnan(y))
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return y;
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if (y == 0)
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return 1;
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if (x == 0)
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return 0;
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if (y == 1)
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return x;
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int y_as_int = (int)y;
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@ -115,40 +119,22 @@ double pow(double x, double y) NOEXCEPT
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result = 1.0 / result;
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return result;
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}
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return exp(y * log(x));
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return exp2(y * log2(x));
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}
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float powf(float x, float y) NOEXCEPT
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{
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// FIXME: Please fix me. I am naive.
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if (y == 0)
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return 1;
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if (y == 1)
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return x;
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int y_as_int = (int)y;
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if (y == (float)y_as_int) {
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float result = x;
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for (int i = 0; i < fabs(y) - 1; ++i)
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result *= x;
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if (y < 0)
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result = 1.0 / result;
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return result;
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}
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return (float)exp((double)y * log((double)x));
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return (float)pow(x, y);
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}
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double ldexp(double x, int exp) NOEXCEPT
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{
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// FIXME: Please fix me. I am naive.
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double val = pow(2, exp);
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return x * val;
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return x * exp2(exp);
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}
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float ldexpf(float x, int exp) NOEXCEPT
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{
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// FIXME: Please fix me. I am naive.
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float val = powf(2, exp);
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return x * val;
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return x * exp2f(exp);
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}
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double tanh(double x) NOEXCEPT
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@ -212,22 +198,28 @@ double sinh(double x) NOEXCEPT
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double log10(double x) NOEXCEPT
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{
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return log(x) / M_LN10;
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double ret = 0.0;
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__asm__(
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"fldlg2\n"
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"fld %%st(1)\n"
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"fyl2x\n"
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"fstp %%st(1)"
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: "=t"(ret)
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: "0"(x));
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return ret;
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}
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double log(double x) NOEXCEPT
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{
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if (x < 0)
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return NAN;
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if (x == 0)
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return -INFINITY;
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double y = 1 + 2 * (x - 1) / (x + 1);
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double exponentiated = exp(y);
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y = y + 2 * (x - exponentiated) / (x + exponentiated);
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exponentiated = exp(y);
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y = y + 2 * (x - exponentiated) / (x + exponentiated);
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exponentiated = exp(y);
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return y + 2 * (x - exponentiated) / (x + exponentiated);
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double ret = 0.0;
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__asm__(
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"fldln2\n"
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"fld %%st(1)\n"
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"fyl2x\n"
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"fstp %%st(1)"
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: "=t"(ret)
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: "0"(x));
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return ret;
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}
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float logf(float x) NOEXCEPT
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@ -247,38 +239,19 @@ float fmodf(float index, float period) NOEXCEPT
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double exp(double exponent) NOEXCEPT
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{
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double result = 1;
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if (exponent >= 1) {
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size_t integer_part = (size_t)exponent;
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if (integer_part & 1)
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result *= e_to_power<1>();
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if (integer_part & 2)
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result *= e_to_power<2>();
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if (integer_part > 3) {
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if (integer_part & 4)
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result *= e_to_power<4>();
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if (integer_part & 8)
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result *= e_to_power<8>();
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if (integer_part & 16)
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result *= e_to_power<16>();
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if (integer_part & 32)
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result *= e_to_power<32>();
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if (integer_part >= 64)
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return INFINITY;
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}
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exponent -= integer_part;
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} else if (exponent < 0)
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return 1 / exp(-exponent);
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double taylor_series_result = 1 + exponent;
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double taylor_series_numerator = exponent * exponent;
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taylor_series_result += taylor_series_numerator / factorial<2>();
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taylor_series_numerator *= exponent;
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taylor_series_result += taylor_series_numerator / factorial<3>();
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taylor_series_numerator *= exponent;
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taylor_series_result += taylor_series_numerator / factorial<4>();
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taylor_series_numerator *= exponent;
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taylor_series_result += taylor_series_numerator / factorial<5>();
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return result * taylor_series_result;
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double res = 0;
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__asm__("fldl2e\n"
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"fmulp\n"
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"fld1\n"
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"fld %%st(1)\n"
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"fprem\n"
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"f2xm1\n"
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"faddp\n"
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"fscale\n"
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"fstp %%st(1)"
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: "=t"(res)
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: "0"(exponent));
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return res;
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}
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float expf(float exponent) NOEXCEPT
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@ -288,12 +261,22 @@ float expf(float exponent) NOEXCEPT
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double exp2(double exponent) NOEXCEPT
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{
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return pow(2.0, exponent);
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double res = 0;
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__asm__("fld1\n"
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"fld %%st(1)\n"
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"fprem\n"
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"f2xm1\n"
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"faddp\n"
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"fscale\n"
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"fstp %%st(1)"
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: "=t"(res)
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: "0"(exponent));
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return res;
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}
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float exp2f(float exponent) NOEXCEPT
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{
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return pow(2.0f, exponent);
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return (float)exp2(exponent);
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}
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double cosh(double x) NOEXCEPT
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@ -380,7 +363,15 @@ double fabs(double value) NOEXCEPT
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double log2(double x) NOEXCEPT
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{
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return log(x) / M_LN2;
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double ret = 0.0;
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__asm__(
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"fld1\n"
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"fld %%st(1)\n"
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"fyl2x\n"
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"fstp %%st(1)"
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: "=t"(ret)
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: "0"(x));
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return ret;
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}
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float log2f(float x) NOEXCEPT
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@ -490,16 +481,45 @@ double gamma(double x) NOEXCEPT
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double expm1(double x) NOEXCEPT
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{
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return pow(M_E, x) - 1;
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return exp(x) - 1;
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}
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double cbrt(double x) NOEXCEPT
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{
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if (x > 0) {
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return pow(x, 1.0 / 3.0);
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if (isinf(x) || x == 0)
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return x;
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if (x < 0)
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return -cbrt(-x);
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double r = x;
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double ex = 0;
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while (r < 0.125) {
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r *= 8;
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ex--;
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}
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while (r > 1.0) {
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r *= 0.125;
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ex++;
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}
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return -pow(-x, 1.0 / 3.0);
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r = (-0.46946116 * r + 1.072302) * r + 0.3812513;
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while (ex < 0) {
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r *= 0.5;
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ex++;
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}
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while (ex > 0) {
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r *= 2;
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ex--;
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}
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r = (2.0 / 3.0) * r + (1.0 / 3.0) * x / (r * r);
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r = (2.0 / 3.0) * r + (1.0 / 3.0) * x / (r * r);
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r = (2.0 / 3.0) * r + (1.0 / 3.0) * x / (r * r);
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r = (2.0 / 3.0) * r + (1.0 / 3.0) * x / (r * r);
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return r;
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}
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double log1p(double x) NOEXCEPT
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