Re: [Bpf] [PATCH bpf-next] bpf, docs: Add signed comparison example

[David Vernet <void@manifault.com>]

On Fri, Mar 10, 2023 at 11:38:14PM +0000, Dave Thaler wrote:
> From: Dave Thaler <dthaler@microsoft.com>
> 
> Improve clarity by adding an example of a signed comparison instruction
> 
> Signed-off-by: Dave Thaler <dthaler@microsoft.com>

Acked-by: David Vernet <void@manifault.com>

> ---
>  Documentation/bpf/instruction-set.rst | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/bpf/instruction-set.rst b/Documentation/bpf/instruction-set.rst
> index 5e43e14abe8..b4464058905 100644
> --- a/Documentation/bpf/instruction-set.rst
> +++ b/Documentation/bpf/instruction-set.rst
> @@ -11,7 +11,8 @@ Documentation conventions
>  =========================
>  
>  For brevity, this document uses the type notion "u64", "u32", etc.
> -to mean an unsigned integer whose width is the specified number of bits.
> +to mean an unsigned integer whose width is the specified number of bits,
> +and "s32", etc. to mean a signed integer of the specified number of bits.
>  
>  Registers and calling convention
>  ================================
> @@ -264,6 +265,14 @@ BPF_JSLE  0xd0   PC += off if dst <= src    signed
>  The eBPF program needs to store the return value into register R0 before doing a
>  BPF_EXIT.
>  
> +Example:
> +
> +``BPF_JSGE | BPF_X | BPF_JMP32`` (0x7e) means::
> +
> +  if (s32)dst s>= (s32)src goto +offset
> +
> +where 's>=' indicates a signed '>=' comparison.
> +
>  Helper functions
>  ~~~~~~~~~~~~~~~~
>  
> -- 
> 2.33.4
> 
> -- 
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