objdump 2.46.1 prints {bad} for VCVTPS2PH encoding generated by NASM

Jiang, Haochen haochen.jiang@intel.com
Tue Aug 18 02:17:13 GMT 2026


> From: Christian Ludloff <ludloff@gmail.com>
> Sent: Monday, August 17, 2026 10:19 PM
> 
> It's as NASM bug.

Definitely. SDM has clearly mentioned in overall SAE encoding part:

The EVEX encoding system allows arithmetic floating-point instructions without rounding semantic to be encoded
with the SAE attribute. This capability applies to scalar and 512-bit vector lengths, register-to-register only, by
setting EVEX.b.

It should be register-register only. When memory kicks in, it is invalid.

It is redundant to mention this for each inst description.

Thx,
Haochen

> 
> https://github.com/netwide-assembler/nasm/issues/295
> 
> (I think you filed it.)
> 
> --
> C.


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