Re: BPF ISA web page

[Vadim Goncharov <vadimnuclight () gmail com>]

On Sat, 8 Nov 2025 19:47:36 +0000
Denis Ovsienko <denis () ovsienko info> wrote:

> Hello all.
>
> Whilst working on some recent improvements in libpcap, I often had to
> cross-reference the source code with the 1993 BPF specification, which
> still seems to be the most detailed definition of the ISA.  The matter
> is, there are various discrepancies between the spec and the code, and
> not every discrepancy is a bug, and it became unwieldy to keep notes of
> what is what, so eventually I decided to make a new resource to bridge
> the 1993 specification and the current implementations:
>
> https://www.tcpdump.org/bpfisa.html
>
> If you think anything is incorrect or missing, let me know.

It should contain not only "mnemonics" (BTW, A and X registers are uppercase)
but also also layout of instruction and actual codes such as BPF_K or BPF_IND.
This will allow reader to understand potential of extensions. When I tried to
design next step of BPF ISA (alternative to eBPF and comaptible to classic
BPF), I've even drawed them like RFC-style diagrams:

https://github.com/nuclight/bpf64/blob/main/bpf64spec.md

-- 
WBR, @nuclight
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