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const NaNs = {
Float16: [
0x7C01, // smallest SNaN
0x7DFF, // largest SNaN
0x7E01, // smallest QNaN
0x7FFF, // largest QNaN
0xFC01, // smallest SNaN, sign-bit set
0xFDFF, // largest SNaN, sign-bit set
0xFE01, // smallest QNaN, sign-bit set
0xFFFF, // largest QNaN, sign-bit set
],
Float32: [
[0x7F80_0001], // smallest SNaN
[0x7FBF_FFFF], // largest SNaN
[0x7FC0_0000], // smallest QNaN
[0x7FFF_FFFF], // largest QNaN
[0xFF80_0001], // smallest SNaN, sign-bit set
[0xFFBF_FFFF], // largest SNaN, sign-bit set
[0xFFC0_0000], // smallest QNaN, sign-bit set
[0xFFFF_FFFF], // largest QNaN, sign-bit set
],
Float64: [
[0x7FF0_0000_0000_0001n], // smallest SNaN
[0x7FF7_FFFF_FFFF_FFFFn], // largest SNaN
[0x7FF8_0000_0000_0000n], // smallest QNaN
[0x7FFF_FFFF_FFFF_FFFFn], // largest QNaN
[0xFFF0_0000_0000_0001n], // smallest SNaN, sign-bit set
[0xFFF7_FFFF_FFFF_FFFFn], // largest SNaN, sign-bit set
[0xFFF8_0000_0000_0000n], // smallest QNaN, sign-bit set
[0xFFFF_FFFF_FFFF_FFFFn], // largest QNaN, sign-bit set
[valueAsRawBits(undefined)],
[valueAsRawBits(null)],
[valueAsRawBits(123456)],
],
};
function assertSameNaNPayload(FloatArray, input, output, message = "") {
if (message) {
message += ": ";
}
let exponentWidth;
let significandWidth;
switch (FloatArray.BYTES_PER_ELEMENT) {
case 8:
exponentWidth = 11n;
significandWidth = 52n;
break;
case 4:
exponentWidth = 8n;
significandWidth = 23n;
break;
case 2:
exponentWidth = 5n;
significandWidth = 10n;
break;
default:
throw "bad typed array";
}
// The exponent bits in the floating point representation.
const exponentBits = ((1n << exponentWidth) - 1n) << significandWidth;
// The significand bits in the floating point representation.
const significandBits = (1n << significandWidth) - 1n;
// Assert `input` is a NaN value.
assertEq(
BigInt(input) & exponentBits,
exponentBits,
message + "all exponent bits must be set"
);
assertEq(
(BigInt(input) & significandBits) !== 0n,
true,
message + "significand must be non-zero"
);
// Assert `output` is a NaN value.
assertEq(
BigInt(output) & exponentBits,
exponentBits,
message + "all exponent bits must be set"
);
assertEq(
(BigInt(output) & significandBits) !== 0n,
true,
message + "significand must be non-zero"
);
// Extract payload and mask off the quiet NaN bit.
let inputPayload = BigInt(input) & (significandBits >> 1n);
let outputPayload = BigInt(output) & (significandBits >> 1n);
// If the output has a NaN payload, then the input must have a payload, too.
if (outputPayload) {
assertEq(
outputPayload,
inputPayload,
`${message}${outputPayload.toString(16)} != ${inputPayload.toString(16)}`
);
}
}
function testWithFloatTypedArrays(f, ...args) {
function testWith(FloatArray, UintArray, NaNs) {
// Create a copy to avoid type pollution.
var clone = Function(`return ${f}`)();
clone(FloatArray, UintArray, NaNs, ...args);
}
testWith(Float64Array, BigUint64Array, NaNs.Float64);
testWith(Float32Array, Uint32Array, NaNs.Float32);
testWith(Float16Array, Uint16Array, NaNs.Float16);
}