[Nasm-bugs] Support for rex.w?

[Marcus Dubois]

Hi,

I'm trying to assemble the following statement with nasm[1] on Ubuntu 20.04

rex.w retf

This should generate the following byte sequence 0x48 0xCB.
But I only seem to get 0xCB. I've tried rex64 instead of rex.w but
the result is the same.

Assembling the above instructions on GNU AS[2] works fine.
My current workaround is to manually input the 0x48 byte inline

db 0x48
retf

But that seems like a hack. Is this a bug or am I missing something?

Best regards,

Marcus

1. NASM version 2.14.02-1
2. binutils version 2.34-6ubuntu1.1
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