Introduce add, sub, and mul for uint32x4 type about ecmascript_simd HOT 3 CLOSED

The current ecmascript_simd.js uses the 2) method as there is a neg and negu32 method in the SIMD object. The addition and subtraction for uint32x4 could be added by addu32 and subu32.

There is no multiply operation in the Dart UInt32 API. It seems that there is no SIMD multiply machine instruction.

from ecmascript_simd.

For uint32x4 addition and subtraction, an implementation issue is how to deal with overflow. John uses addpl and subpl in the Dart implementation and I did not see overflow handling in the code. We might need to document the expected behavior or the behavior is implementation defined in the proposal.

from ecmascript_simd.

I've added:

SIMD.addu32
SIMD.subu32
SIMD.mulu32

Along with some tests.

from ecmascript_simd.