x86 WBINVD prefix allocations
Project / Subsystem
binutils / binutils
Date
2026-08-28
Proposer
Christian Ludloff <ludloff@gmail.com>
Source type
public_inbox
Consensus
Proposed
Sentiment
—/10
Technical tradeoffs
- • Ensures assembler/linker support for evolving x86 instruction prefixes.
- • Avoids potential conflicts with new, actively used cache control hints.
All attributes
- project
- binutils
- subsystem
- binutils
- patch_id
- —
- discussion_id
- CAKSQd8V-m4oi-JhyxH3Y4KsLhf_CNFaVqbyJbNdd237FspndGA@mail.gmail.com
- source_type
- public_inbox
- title
- x86 WBINVD prefix allocations
- headline
- x86 WBINVD instruction prefix usage
- tldr
- Discussion on the correct allocation and usage of prefixes for the x86 WBINVD instruction, especially with new 'skip hints'.
- proposer
- Christian Ludloff <ludloff@gmail.com>
- consensus
- Proposed
- outcome
- proposed
- sentiment_score
- —
- technical_tradeoffs
-
- • Ensures assembler/linker support for evolving x86 instruction prefixes.
- • Avoids potential conflicts with new, actively used cache control hints.
- series_id
- —
- series_role
- standalone
- series_parts
- []
- tags
-
- • x86
- • binutils
- • assembly
- • CPU cache
- bugzilla_url
- —
- date
- 2026-08-28T00:00:00.000Z
x86 WBINVD prefix allocations
Christian Ludloff brings attention to the usage of prefixes with the x86 WBINVD instruction, noting that new ‘skip hints’ (0x67, 0x66, 0xF3, 0xF2, and implementation-specific prefixes) are in active use by a corporate entity. The discussion clarifies that these prefixes modify the cache behavior of WBINVD without introducing new CPUID flags. The goal is to ensure binutils correctly handles these prefixes as they are being adopted.