What about subnormals? · Issue #148 · WebAssembly/design (original) (raw)

Forking from: #141 (comment)

Should denormal be:

• Unspecified (say so in Nondeterminism.md).
• Fully specified as IEEE-754 compliance.
• Fully specified as IEEE-754 compliance for scalars, and do something for SIMD because existing hardware (especially ARMv7 NEON) doesn't support denormals.
• Specified as DAZ/FTZ (not IEEE-754 compliant).

We should probably let ourselves change this from developer feedback, but I'd like to make some decision for MVP. I suggested on esdiscuss that JavaScript go full unspecified, and just do DAZ/FTZ because it's often faster. Yes, x86 is better than it used to be but that's not universal, ignores current hardware, and doesn't look towards what new hardware will do. I like leaving the door open :-)

For @sunfishcode searchability, I'll use the word "subnormals" too :-)