`round2` flips the sign when rounding the smallest subnormal (negative input)

[manit2004]

Description

round2(-Number.MIN_VALUE) returns the positive smallest subnormal instead of the negative one. Found this while digging through math/base/special.

The function does the usual if (x < 0) { x = -x; sign = -1; } thing up front so the rest of the body only deals with magnitudes, then multiplies back by sign on every return path; except one. There's an early-return for "this is exactly the smallest subnormal, can't round it any further":

if ( p === MIN_EXP_SUBNORMAL ) {
    return x;   // <-- x is already the abs value at this point, sign is dropped
}

Since x was already reassigned to its absolute value two lines earlier, this just returns the magnitude, not the original signed input. Every other branch in the function (sign * PINF, sign * HUGE, sign * y1, sign * y2) gets this right; this one spot doesn't.

Existing test suite doesn't catch it; it only checks round2(SMALLEST_SUBNORMAL) (positive), never the negative case, so sign being +1 there masked the bug.

Related Issues

None

Questions

No.

Demo

No response

Reproduction

var round2 = require( '@stdlib/math/base/special/round2' );

var v = round2( -Number.MIN_VALUE ); // -5e-324
// returns 5e-324, should return -5e-324

Expected Results:

-5e-324 (sign preserved, matching every other return path in the function).

Actual Results:

5e-324 — sign silently flipped.

Expected Results

`-5e-324` (sign preserved, matching every other return path in the function).

Actual Results

`5e-324` — sign silently flipped.

Version

0.4.1

Environments

Node.js

Browser Version

No response

Node.js / npm Version

Node v22.22.2, npm 10.9.7

Platform

No response

Checklist

• Read and understood the Code of Conduct.
• Searched for existing issues and pull requests.