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140 lines
2.2 KiB
140 lines
2.2 KiB
/*
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* ToUint16() (E5 Section 9.7).
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*
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* Indirect testing using String.fromCharCode() (which seems to be the
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* only caller for this internal coercion!). ToUint16() first coerces
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* with ToNumber(), so that is noted in the cases.
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*/
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function touint16(x) {
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var str = String.fromCharCode(x); // Coerce with ToUint16 (E5 Section 15.5.3.2)
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return str.charCodeAt(0); // Read back
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}
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function zeroSign(x) {
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if (x !== 0) {
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return 'nz';
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}
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if (1 / x > 0) {
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return 'pos';
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} else {
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return 'neg';
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}
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}
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function test(x) {
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var t = touint16(x);
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print(t, zeroSign(t));
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}
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/*===
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0 pos
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===*/
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// ToNumber(undefined) -> NaN -> +0
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test(undefined);
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/*===
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0 pos
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===*/
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// ToNumber(null) -> +0 -> +0
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test(null);
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/*===
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1 nz
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0 pos
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===*/
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// ToNumber(true) -> 1 -> 1
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test(true);
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// Tonumber(false) -> +0 -> +0
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test(false);
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/*===
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0 pos
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0 pos
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0 pos
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0 pos
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0 pos
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===*/
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// ToNumber(NaN) -> NaN -> +0
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test(NaN);
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// ToNumber(+0) -> +0 -> +0
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test(+0);
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// ToNumber(-0) -> -0 -> +0
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test(-0);
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// ToNumber(+Infinity) -> +Infinity -> +0
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test(Number.POSITIVE_INFINITY);
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// ToNumber(-Infinity) -> -Infinity -> +0
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test(Number.NEGATIVE_INFINITY);
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/*===
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123 nz
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65413 nz
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0 pos
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0 pos
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0 pos
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0 pos
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0 pos
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0 pos
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0 pos
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58368 nz
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===*/
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/* ToNumber() string coercion, E5 Section 9.3.1 */
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test("123");
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test("-123");
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test("+0");
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test("-0");
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test("Infinity");
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test("+Infinity");
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test("-Infinity");
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test("NaN"); // "NaN" does not parse -> results in NaN number -> +0
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test("NaY"); // same case
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test("1e10"); // larger than 32-bit, fits in 53 bits of double
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/* XXX: object coercion */
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/*===
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0 pos
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1 nz
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65535 nz
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2 nz
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65535 nz
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0 pos
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2 nz
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===*/
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/* A couple of modulo tests */
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test(4294967296);
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test(4294967297);
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test(-1); // --> 0xffffU
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test(-4294967294); // +2
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test(9007199254740991); // (2^53 - 1) % (2^32) --> 4294967295 --> 65535
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test(9007199254740992); // (2^53) % (2^32) --> 0
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test(9007199254740994); // (2^53 + 2) % (2^32) --> 2 (Note: 2^53+1 not representable)
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/*===
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3 nz
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65533 nz
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===*/
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/* Rounding
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*
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* Positive numbers: x -> floor(x) e.g. 3.4 -> 3
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* Negative numbers: -x -> -floor(x) e.g. -3.4 -> -3 (not -4)
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*/
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test(3.4); // -> 3 -> 3
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test(-3.4); // -> -3 -> (2^32) - 3
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