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Diffstat (limited to 'js/src/tests/non262/BigInt/Number-conversion-rounding.js')
| -rw-r--r-- | js/src/tests/non262/BigInt/Number-conversion-rounding.js | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/js/src/tests/non262/BigInt/Number-conversion-rounding.js b/js/src/tests/non262/BigInt/Number-conversion-rounding.js new file mode 100644 index 0000000000..5daf68948d --- /dev/null +++ b/js/src/tests/non262/BigInt/Number-conversion-rounding.js @@ -0,0 +1,244 @@ +// Any copyright is dedicated to the Public Domain. +// https://creativecommons.org/licenses/publicdomain/ + +/** + * Edge-case behavior at Number.MAX_VALUE and beyond til overflow to Infinity. + */ +function maxMagnitudeTests(isNegative) +{ + var sign = isNegative ? -1 : +1; + var signBigInt = isNegative ? -1n : 1n; + + const MAX_VALUE = isNegative ? -Number.MAX_VALUE : +Number.MAX_VALUE; + + // 2**971+2**972+...+2**1022+2**1023 + var maxMagnitudeNumber = 0; + for (let i = 971; i < 1024; i++) + maxMagnitudeNumber += 2**i; + maxMagnitudeNumber *= sign; + assertEq(maxMagnitudeNumber, MAX_VALUE); + + // 2**971+2**972+...+2**1022+2**1023 + var maxMagnitudeNumberAsBigInt = 0n; + for (let i = 971n; i < 1024n; i++) + maxMagnitudeNumberAsBigInt += 2n**i; + maxMagnitudeNumberAsBigInt *= signBigInt; + var expectedMaxMagnitude = isNegative + ? -(2n**1024n) + 2n**971n + : 2n**1024n - 2n**971n; + assertEq(maxMagnitudeNumberAsBigInt, expectedMaxMagnitude); + + // Initial sanity tests. + assertEq(BigInt(maxMagnitudeNumber), maxMagnitudeNumberAsBigInt); + assertEq(maxMagnitudeNumber, Number(maxMagnitudeNumberAsBigInt)); + + // Test conversion of BigInt values above Number.MAX_VALUE. + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 1n), MAX_VALUE); + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 2n), MAX_VALUE); + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 3n), MAX_VALUE); + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 4n), MAX_VALUE); + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 5n), MAX_VALUE); + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 6n), MAX_VALUE); + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 7n), MAX_VALUE); + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 8n), MAX_VALUE); + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 9n), MAX_VALUE); + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 2n**20n), MAX_VALUE); + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 2n**400n), MAX_VALUE); + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 2n**800n), MAX_VALUE); + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 2n**900n), MAX_VALUE); + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 2n**969n), MAX_VALUE); + + // For conversion purposes, rounding for values above Number.MAX_VALUE do + // rounding with respect to Number.MAX_VALUE and 2**1024 (which is treated as + // the "even" value -- so if the value to convert lies halfway between those two + // values, 2**1024 is selected). But if 2**1024 is the value that *would* have + // been chosen by this process, Infinity is substituted. + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * (2n**970n - 1n)), MAX_VALUE); + assertEq(Number(maxMagnitudeNumberAsBigInt + signBigInt * 2n**970n), sign * Infinity); +} +maxMagnitudeTests(false); +maxMagnitudeTests(true); + +/** + * Simple single-Digit on x64, double-Digit on x86 tests. + */ + +assertEq(BigInt(Number(2n**53n - 2n)), 2n**53n - 2n); +assertEq(BigInt(Number(2n**53n - 1n)), 2n**53n - 1n); +assertEq(BigInt(Number(2n**53n)), 2n**53n); +assertEq(BigInt(Number(2n**53n + 1n)), 2n**53n); +assertEq(BigInt(Number(2n**53n + 2n)), 2n**53n + 2n); +assertEq(BigInt(Number(2n**53n + 3n)), 2n**53n + 4n); +assertEq(BigInt(Number(2n**53n + 4n)), 2n**53n + 4n); +assertEq(BigInt(Number(2n**53n + 5n)), 2n**53n + 4n); +assertEq(BigInt(Number(2n**53n + 6n)), 2n**53n + 6n); +assertEq(BigInt(Number(2n**53n + 7n)), 2n**53n + 8n); +assertEq(BigInt(Number(2n**53n + 8n)), 2n**53n + 8n); + +assertEq(BigInt(Number(2n**54n - 4n)), 2n**54n - 4n); +assertEq(BigInt(Number(2n**54n - 3n)), 2n**54n - 4n); +assertEq(BigInt(Number(2n**54n - 2n)), 2n**54n - 2n); +assertEq(BigInt(Number(2n**54n - 1n)), 2n**54n); +assertEq(BigInt(Number(2n**54n)), 2n**54n); +assertEq(BigInt(Number(2n**54n + 1n)), 2n**54n); +assertEq(BigInt(Number(2n**54n + 2n)), 2n**54n); +assertEq(BigInt(Number(2n**54n + 3n)), 2n**54n + 4n); +assertEq(BigInt(Number(2n**54n + 4n)), 2n**54n + 4n); +assertEq(BigInt(Number(2n**54n + 5n)), 2n**54n + 4n); +assertEq(BigInt(Number(2n**54n + 6n)), 2n**54n + 8n); +assertEq(BigInt(Number(2n**54n + 7n)), 2n**54n + 8n); +assertEq(BigInt(Number(2n**54n + 8n)), 2n**54n + 8n); + +assertEq(BigInt(Number(2n**55n - 8n)), 2n**55n - 8n); +assertEq(BigInt(Number(2n**55n - 7n)), 2n**55n - 8n); +assertEq(BigInt(Number(2n**55n - 6n)), 2n**55n - 8n); +assertEq(BigInt(Number(2n**55n - 5n)), 2n**55n - 4n); +assertEq(BigInt(Number(2n**55n - 4n)), 2n**55n - 4n); +assertEq(BigInt(Number(2n**55n - 3n)), 2n**55n - 4n); +assertEq(BigInt(Number(2n**55n - 2n)), 2n**55n); +assertEq(BigInt(Number(2n**55n - 1n)), 2n**55n); +assertEq(BigInt(Number(2n**55n)), 2n**55n); +assertEq(BigInt(Number(2n**55n + 1n)), 2n**55n); +assertEq(BigInt(Number(2n**55n + 2n)), 2n**55n); +assertEq(BigInt(Number(2n**55n + 3n)), 2n**55n); +assertEq(BigInt(Number(2n**55n + 4n)), 2n**55n); +assertEq(BigInt(Number(2n**55n + 5n)), 2n**55n + 8n); +assertEq(BigInt(Number(2n**55n + 6n)), 2n**55n + 8n); +assertEq(BigInt(Number(2n**55n + 7n)), 2n**55n + 8n); +assertEq(BigInt(Number(2n**55n + 8n)), 2n**55n + 8n); +assertEq(BigInt(Number(2n**55n + 9n)), 2n**55n + 8n); +assertEq(BigInt(Number(2n**55n + 10n)), 2n**55n + 8n); +assertEq(BigInt(Number(2n**55n + 11n)), 2n**55n + 8n); +assertEq(BigInt(Number(2n**55n + 12n)), 2n**55n + 16n); +assertEq(BigInt(Number(2n**55n + 13n)), 2n**55n + 16n); +assertEq(BigInt(Number(2n**55n + 14n)), 2n**55n + 16n); +assertEq(BigInt(Number(2n**55n + 15n)), 2n**55n + 16n); +assertEq(BigInt(Number(2n**55n + 16n)), 2n**55n + 16n); + + +/** + * Simple double-Digit on x64, triple-Digit on x86 tests. + */ + +// The tests below that aren't subtracting bits will have no bits in the +// ultimate significand from the most-significant digit (because of the implicit +// one being excluded). +assertEq(BigInt(Number(2n**64n - 2n**11n)), 2n**64n - 2n**11n); +assertEq(BigInt(Number(2n**64n - 2n**11n + 2n**10n - 1n)), 2n**64n - 2n**11n); +assertEq(BigInt(Number(2n**64n - 2n**11n + 2n**10n)), 2n**64n); +assertEq(BigInt(Number(2n**64n - 2n**10n)), 2n**64n); +assertEq(BigInt(Number(2n**64n)), 2n**64n); +assertEq(BigInt(Number(2n**64n + 1n)), 2n**64n); +assertEq(BigInt(Number(2n**64n + 2n**5n)), 2n**64n); +assertEq(BigInt(Number(2n**64n + 2n**10n)), 2n**64n); +assertEq(BigInt(Number(2n**64n + 2n**11n)), 2n**64n); +assertEq(BigInt(Number(2n**64n + 2n**11n + 1n)), 2n**64n + 2n**12n); +assertEq(BigInt(Number(2n**64n + 2n**12n)), 2n**64n + 2n**12n); +assertEq(BigInt(Number(2n**64n + 2n**12n + 1n)), 2n**64n + 2n**12n); +assertEq(BigInt(Number(2n**64n + 2n**12n + 2n**5n)), 2n**64n + 2n**12n); +assertEq(BigInt(Number(2n**64n + 2n**12n + 2n**10n)), 2n**64n + 2n**12n); +assertEq(BigInt(Number(2n**64n + 2n**12n + 2n**11n - 1n)), 2n**64n + 2n**12n); +assertEq(BigInt(Number(2n**64n + 2n**12n + 2n**11n)), 2n**64n + 2n**13n); +assertEq(BigInt(Number(2n**64n + 2n**12n + 2n**11n + 1n)), 2n**64n + 2n**13n); + +// These tests *will* have a bit from the most-significant digit in the ultimate +// significand. +assertEq(BigInt(Number(2n**65n - 2n**12n)), 2n**65n - 2n**12n); +assertEq(BigInt(Number(2n**65n - 2n**12n + 2n**11n - 1n)), 2n**65n - 2n**12n); +assertEq(BigInt(Number(2n**65n - 2n**12n + 2n**11n)), 2n**65n); +assertEq(BigInt(Number(2n**65n - 2n**11n)), 2n**65n); +assertEq(BigInt(Number(2n**65n)), 2n**65n); +assertEq(BigInt(Number(2n**65n + 1n)), 2n**65n); +assertEq(BigInt(Number(2n**65n + 2n**5n)), 2n**65n); +assertEq(BigInt(Number(2n**65n + 2n**11n)), 2n**65n); +assertEq(BigInt(Number(2n**65n + 2n**12n)), 2n**65n); +assertEq(BigInt(Number(2n**65n + 2n**12n + 1n)), 2n**65n + 2n**13n); +assertEq(BigInt(Number(2n**65n + 2n**13n)), 2n**65n + 2n**13n); +assertEq(BigInt(Number(2n**65n + 2n**13n + 1n)), 2n**65n + 2n**13n); +assertEq(BigInt(Number(2n**65n + 2n**13n + 2n**5n)), 2n**65n + 2n**13n); +assertEq(BigInt(Number(2n**65n + 2n**13n + 2n**11n)), 2n**65n + 2n**13n); +assertEq(BigInt(Number(2n**65n + 2n**13n + 2n**12n - 1n)), 2n**65n + 2n**13n); +assertEq(BigInt(Number(2n**65n + 2n**13n + 2n**12n)), 2n**65n + 2n**14n); +assertEq(BigInt(Number(2n**65n + 2n**13n + 2n**12n + 1n)), 2n**65n + 2n**14n); + +// ...and in these tests, the contributed bit from the most-significant digit +// is additionally nonzero. +assertEq(BigInt(Number(2n**65n + 2n**64n)), 2n**65n + 2n**64n); +assertEq(BigInt(Number(2n**65n + 2n**64n + 1n)), 2n**65n + 2n**64n); +assertEq(BigInt(Number(2n**65n + 2n**64n + 2n**5n)), 2n**65n + 2n**64n); +assertEq(BigInt(Number(2n**65n + 2n**64n + 2n**11n)), 2n**65n + 2n**64n); +assertEq(BigInt(Number(2n**65n + 2n**64n + 2n**12n)), 2n**65n + 2n**64n); +assertEq(BigInt(Number(2n**65n + 2n**64n + 2n**12n + 1n)), 2n**65n + 2n**64n + 2n**13n); +assertEq(BigInt(Number(2n**65n + 2n**64n + 2n**13n)), 2n**65n + 2n**64n + 2n**13n); +assertEq(BigInt(Number(2n**65n + 2n**64n + 2n**13n + 1n)), 2n**65n + 2n**64n + 2n**13n); +assertEq(BigInt(Number(2n**65n + 2n**64n + 2n**13n + 2n**5n)), 2n**65n + 2n**64n + 2n**13n); +assertEq(BigInt(Number(2n**65n + 2n**64n + 2n**13n + 2n**11n)), 2n**65n + 2n**64n + 2n**13n); +assertEq(BigInt(Number(2n**65n + 2n**64n + 2n**13n + 2n**12n - 1n)), 2n**65n + 2n**64n + 2n**13n); +assertEq(BigInt(Number(2n**65n + 2n**64n + 2n**13n + 2n**12n)), 2n**65n + 2n**64n + 2n**14n); +assertEq(BigInt(Number(2n**65n + 2n**64n + 2n**13n + 2n**12n + 1n)), 2n**65n + 2n**64n + 2n**14n); + +/** + * Versions of the testing above with all the high-order bits massively bumped + * upward to test that super-low bits, not just bits in high digits, are + * properly accounted for in rounding. + */ + +// The tests below that aren't subtracting bits will have no bits in the +// ultimate significand from the most-significant digit (because of the implicit +// one being excluded). +assertEq(BigInt(Number(2n**940n - 2n**887n + 1n)), 2n**940n - 2n**887n); +assertEq(BigInt(Number(2n**940n - 2n**887n + 2n**886n - 1n)), 2n**940n - 2n**887n); +assertEq(BigInt(Number(2n**940n - 2n**887n + 2n**886n)), 2n**940n); +assertEq(BigInt(Number(2n**940n - 2n**886n)), 2n**940n); +assertEq(BigInt(Number(2n**940n)), 2n**940n); +assertEq(BigInt(Number(2n**940n + 1n)), 2n**940n); +assertEq(BigInt(Number(2n**940n + 2n**880n)), 2n**940n); +assertEq(BigInt(Number(2n**940n + 2n**885n)), 2n**940n); +assertEq(BigInt(Number(2n**940n + 2n**887n)), 2n**940n); +assertEq(BigInt(Number(2n**940n + 2n**887n + 1n)), 2n**940n + 2n**888n); +assertEq(BigInt(Number(2n**940n + 2n**888n)), 2n**940n + 2n**888n); +assertEq(BigInt(Number(2n**940n + 2n**888n + 1n)), 2n**940n + 2n**888n); +assertEq(BigInt(Number(2n**940n + 2n**888n + 2n**5n)), 2n**940n + 2n**888n); +assertEq(BigInt(Number(2n**940n + 2n**888n + 2n**12n)), 2n**940n + 2n**888n); +assertEq(BigInt(Number(2n**940n + 2n**888n + 2n**887n - 1n)), 2n**940n + 2n**888n); +assertEq(BigInt(Number(2n**940n + 2n**888n + 2n**887n)), 2n**940n + 2n**889n); +assertEq(BigInt(Number(2n**940n + 2n**888n + 2n**887n + 1n)), 2n**940n + 2n**889n); + +// These tests *will* have a bit from the most-significant digit in the ultimate +// significand. +assertEq(BigInt(Number(2n**941n - 2n**888n)), 2n**941n - 2n**888n); +assertEq(BigInt(Number(2n**941n - 2n**888n + 2n**887n - 1n)), 2n**941n - 2n**888n); +assertEq(BigInt(Number(2n**941n - 2n**888n + 2n**887n)), 2n**941n); +assertEq(BigInt(Number(2n**941n - 2n**887n)), 2n**941n); +assertEq(BigInt(Number(2n**941n)), 2n**941n); +assertEq(BigInt(Number(2n**941n + 1n)), 2n**941n); +assertEq(BigInt(Number(2n**941n + 2n**881n)), 2n**941n); +assertEq(BigInt(Number(2n**941n + 2n**886n)), 2n**941n); +assertEq(BigInt(Number(2n**941n + 2n**888n)), 2n**941n); +assertEq(BigInt(Number(2n**941n + 2n**888n + 1n)), 2n**941n + 2n**889n); +assertEq(BigInt(Number(2n**941n + 2n**889n)), 2n**941n + 2n**889n); +assertEq(BigInt(Number(2n**941n + 2n**889n + 1n)), 2n**941n + 2n**889n); +assertEq(BigInt(Number(2n**941n + 2n**889n + 2n**5n)), 2n**941n + 2n**889n); +assertEq(BigInt(Number(2n**941n + 2n**889n + 2n**12n)), 2n**941n + 2n**889n); +assertEq(BigInt(Number(2n**941n + 2n**889n + 2n**888n - 1n)), 2n**941n + 2n**889n); +assertEq(BigInt(Number(2n**941n + 2n**889n + 2n**888n)), 2n**941n + 2n**890n); +assertEq(BigInt(Number(2n**941n + 2n**889n + 2n**888n + 1n)), 2n**941n + 2n**890n); + +// ...and in these tests, the contributed bit from the most-significant digit +// is additionally nonzero. +assertEq(BigInt(Number(2n**941n + 2n**940n)), 2n**941n + 2n**940n); +assertEq(BigInt(Number(2n**941n + 2n**940n + 1n)), 2n**941n + 2n**940n); +assertEq(BigInt(Number(2n**941n + 2n**940n + 2n**881n)), 2n**941n + 2n**940n); +assertEq(BigInt(Number(2n**941n + 2n**940n + 2n**886n)), 2n**941n + 2n**940n); +assertEq(BigInt(Number(2n**941n + 2n**940n + 2n**888n)), 2n**941n + 2n**940n); +assertEq(BigInt(Number(2n**941n + 2n**940n + 2n**888n + 1n)), 2n**941n + 2n**940n + 2n**889n); +assertEq(BigInt(Number(2n**941n + 2n**940n + 2n**889n)), 2n**941n + 2n**940n + 2n**889n); +assertEq(BigInt(Number(2n**941n + 2n**940n + 2n**889n + 1n)), 2n**941n + 2n**940n + 2n**889n); +assertEq(BigInt(Number(2n**941n + 2n**940n + 2n**889n + 2n**5n)), 2n**941n + 2n**940n + 2n**889n); +assertEq(BigInt(Number(2n**941n + 2n**940n + 2n**889n + 2n**12n)), 2n**941n + 2n**940n + 2n**889n); +assertEq(BigInt(Number(2n**941n + 2n**940n + 2n**889n + 2n**888n - 1n)), 2n**941n + 2n**940n + 2n**889n); +assertEq(BigInt(Number(2n**941n + 2n**940n + 2n**889n + 2n**888n)), 2n**941n + 2n**940n + 2n**890n); +assertEq(BigInt(Number(2n**941n + 2n**940n + 2n**889n + 2n**888n + 1n)), 2n**941n + 2n**940n + 2n**890n); + +if (typeof reportCompare === "function") + reportCompare(true, true); |