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* C3_MATH feature This feature allows the usage of noclib math files even when libc is in use. If a nolibc symbol exists, it will be used in place of libc, otherwise it will default to libc. * Added MIT License notices to atan.c3
78 lines
1.3 KiB
Plaintext
78 lines
1.3 KiB
Plaintext
module std::math::nolibc @if(env::NO_LIBC || $feature(C3_MATH));
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union DoubleInternal
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{
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double f;
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ulong i;
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}
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// Based on the musl implementation
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fn double fmod(double x, double y) @extern("fmod") @weak @nostrip
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{
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DoubleInternal ux = { .f = x };
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DoubleInternal uy = { .f = y };
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int ex = (int)((ux.i >> 52) & 0x7ff);
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int ey = (int)((uy.i >> 52) & 0x7ff);
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int sx = (int)(ux.i >> 63);
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ulong uxi = ux.i;
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if (uy.i << 1 == 0 || math::is_nan(y) || ex == 0x7ff) return (x * y)/(x * y);
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if (uxi << 1 <= uy.i << 1)
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{
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if (uxi << 1 == uy.i << 1) return 0 * x;
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return x;
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}
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if (!ex)
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{
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for (ulong i = uxi << 12; i >> 63 == 0; ex--, i <<= 1);
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uxi <<= -ex + 1;
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}
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else
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{
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uxi &= -1UL >> 12;
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uxi |= 1UL << 52;
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}
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if (!ey)
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{
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for (ulong i = uy.i << 12; i >> 63 == 0; ey--, i <<= 1);
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uy.i <<= -ey + 1;
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}
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else
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{
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uy.i &= -1UL >> 12;
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uy.i |= 1UL << 52;
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}
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/* x mod y */
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for (; ex > ey; ex--)
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{
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ulong i = uxi - uy.i;
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if (i >> 63 == 0)
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{
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if (i == 0) return 0 * x;
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uxi = i;
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}
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uxi <<= 1;
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}
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ulong i = uxi - uy.i;
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if (i >> 63 == 0)
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{
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if (i == 0) return 0*x;
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uxi = i;
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}
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for (; uxi>>52 == 0; uxi <<= 1, ex--);
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/* scale result */
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if (ex > 0)
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{
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uxi -= 1UL << 52;
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uxi |= (ulong)ex << 52;
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}
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else
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{
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uxi >>= -ex + 1;
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}
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uxi |= (ulong)sx << 63;
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ux.i = uxi;
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return ux.f;
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} |