ambiguity of the effect of instructions

[kam1986]

Is there any difference in effect of the two instructions i64.extend32_s and i64.extend_i32_s or are they just dublicates?

I have look at the documentation document for both versions and 2 and as far I can see they do the exact same operation (page 63 and 73) version 1.

[rossberg]

The former has type i64 → i64, the latter type i32 → i64. So they differ in how the operand is represented.

That said, I agree that something seems to be amiss in the specification – i64.extend32_s should extend the lower half of its operand, but the current definition of iextend fails to filter out the other bits. I think it should be

iextendM_s_N(i) = extend^s_M,N(wrap_N,M(i))

[kam1986]

Thanks that helped

[rossberg]

See #1696.