wasmtime / PR #2771 Implements convert low signed integer... · git-wasmtime

I mean, it's not like the SIMD documentation is much more verbose... perhaps that should get fixed too. I think we need to say something about how the two lowest i32s in the vector (lanes 0 and 1) are the ones converted to the f64. From the Intel reference:

CVTDQ2PD (128-bit Legacy SSE version)
DEST[63:0] := Convert_Integer_To_Double_Precision_Floating_Point(SRC[31:0])
DEST[127:64] := Convert_Integer_To_Double_Precision_Floating_Point(SRC[63:32])
DEST[MAXVL-1:128] (unmodified)

Wasmtime GitHub notifications bot (Mar 26 2021 at 16:31):

abrown edited PR Review Comment.

Wasmtime GitHub notifications bot (Mar 26 2021 at 16:47):

cfallin submitted PR Review.

Wasmtime GitHub notifications bot (Mar 26 2021 at 17:49):

jlb6740 submitted PR Review.

Wasmtime GitHub notifications bot (Mar 26 2021 at 17:49):

jlb6740 created PR Review Comment:

Yes, this is a good point. In updating the comments I just used language of half. That is because the "fcvt_low_from_sint" can also support AVX-512 where we could convert the "four" lowest i32s. That instruction doesn't exist of course in the spec, but could be a candidate for a future iteration of the spec or relaxed simd.

Wasmtime GitHub notifications bot (Mar 26 2021 at 17:56):

jlb6740 updated PR #2771 from x64_simd_convert_i32_to_f64 to main.

Wasmtime GitHub notifications bot (Mar 26 2021 at 19:13):

jlb6740 merged PR #2771.

Last updated: Nov 22 2024 at 17:03 UTC