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Add quickjs-2021-03-27 to third_party

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Justine Tunney 2021-04-08 20:55:43 -07:00
parent f40f97bd07
commit 1fbfbb3192
67 changed files with 99832 additions and 0 deletions
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68
third_party/quickjs/examples/pi_bigdecimal.js vendored Normal file
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/*
* PI computation in Javascript using the QuickJS bigdecimal type
* (decimal floating point)
*/
"use strict";
/* compute PI with a precision of 'prec' digits */
function calc_pi(prec) {
const CHUD_A = 13591409m;
const CHUD_B = 545140134m;
const CHUD_C = 640320m;
const CHUD_C3 = 10939058860032000m; /* C^3/24 */
const CHUD_DIGITS_PER_TERM = 14.18164746272548; /* log10(C/12)*3 */
/* return [P, Q, G] */
function chud_bs(a, b, need_G) {
var c, P, Q, G, P1, Q1, G1, P2, Q2, G2, b1;
if (a == (b - 1n)) {
b1 = BigDecimal(b);
G = (2m * b1 - 1m) * (6m * b1 - 1m) * (6m * b1 - 5m);
P = G * (CHUD_B * b1 + CHUD_A);
if (b & 1n)
P = -P;
G = G;
Q = b1 * b1 * b1 * CHUD_C3;
} else {
c = (a + b) >> 1n;
[P1, Q1, G1] = chud_bs(a, c, true);
[P2, Q2, G2] = chud_bs(c, b, need_G);
P = P1 * Q2 + P2 * G1;
Q = Q1 * Q2;
if (need_G)
G = G1 * G2;
else
G = 0m;
}
return [P, Q, G];
}
var n, P, Q, G;
/* number of serie terms */
n = BigInt(Math.ceil(prec / CHUD_DIGITS_PER_TERM)) + 10n;
[P, Q, G] = chud_bs(0n, n, false);
Q = BigDecimal.div(Q, (P + Q * CHUD_A),
{ roundingMode: "half-even",
maximumSignificantDigits: prec });
G = (CHUD_C / 12m) * BigDecimal.sqrt(CHUD_C,
{ roundingMode: "half-even",
maximumSignificantDigits: prec });
return Q * G;
}
(function() {
var r, n_digits, n_bits;
if (typeof scriptArgs != "undefined") {
if (scriptArgs.length < 2) {
print("usage: pi n_digits");
return;
}
n_digits = scriptArgs[1] | 0;
} else {
n_digits = 1000;
}
/* we add more digits to reduce the probability of bad rounding for
the last digits */
r = calc_pi(n_digits + 20);
print(r.toFixed(n_digits, "down"));
})();