mirror of
https://github.com/fluencelabs/assemblyscript
synced 2025-04-26 07:22:21 +00:00
63 lines
1.4 KiB
TypeScript
63 lines
1.4 KiB
TypeScript
export function fmod(x: f64, y: f64): f64 {
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// the following is based on musl's implementation of fmod
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var ux = reinterpret<f64,u64>(x);
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var uy = reinterpret<f64,u64>(y);
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var ex = <i32>(ux >> 52 & 0x7ff);
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var ey = <i32>(uy >> 52 & 0x7ff);
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var sx = <i32>(ux >> 63);
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if (uy << 1 == 0 || isNaN<f64>(y) || ex == 0x7ff)
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return (x * y) / (x * y);
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if (ux << 1 <= uy << 1) {
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if (ux << 1 == uy << 1)
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return 0 * x;
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return x;
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}
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if (!ex) {
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for (var i = ux << 12; !(i >> 63); ex--) i <<= 1;
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ux <<= -ex + 1;
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} else {
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ux &= -1 >> 12;
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ux |= 1 << 52;
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}
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if (!ey) {
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for (i = uy << 12; !(i >> 63); ey--) i <<= 1;
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uy <<= -ey + 1;
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} else {
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uy &= -1 >> 12;
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uy |= 1 << 52;
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}
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for (; ex > ey; ex--) {
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i = ux - uy;
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if (!(i >> 63)) {
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if (!i)
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return 0 * x;
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ux = i;
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}
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ux <<= 1;
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}
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i = ux - uy;
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if (!(i >> 63)) {
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if (!i)
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return 0 * x;
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ux = i;
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}
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for (; !(ux >> 52); ex--) ux <<= 1;
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if (ex > 0) {
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ux -= 1 << 52;
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ux |= <u64>ex << 52;
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} else {
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ux >>= -ex + 1;
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}
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ux |= <u64>sx << 63;
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return reinterpret<u64,f64>(ux);
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}
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assert(isNaN<f64>(fmod(1, NaN)));
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assert(fmod(1.5, 1.0) == 0.5); // exactly 0.5 (as in C)
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assert(fmod(9.2, 2.0) - 1.2 < f64.EPSILON); // not exactly 1.2 (as in C)
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assert(fmod(9.2, 3.7) - 1.8 < f64.EPSILON); // not exactly 1.8 (as in C)
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