> On Sun, 2023-07-23 at 21:14 +0200, Jose E. Marchesi wrote: >> > On Fri, 2023-07-21 at 18:19 +0200, Jose E. Marchesi wrote: >> > > Hi Yonghong. >> > > >> > > This is from the v4 instructions proposal: >> > > >> > > ======== ===== ========================= ============ >> > > code value description notes >> > > ======== ===== ========================= ============ >> > > BPF_JA 0x00 PC += imm BPF_JMP32 only >> > > >> > > Is this instruction using source 1 instead of 0? Otherwise, it would >> > > have exactly the same encoding than the V3< JA instruction. Is that >> > > what is intended? >> > > >> > > TIA. >> > > >> > >> > Hi Jose, >> > >> > I think that assumption is that `BPF_JMP32 | BPF_JA` is currently free: >> > - documentation [1] implies that only `BPF_JMP` should be used for `BPF_JA` >> > (see "notes" column for the first line) >> > - BPF verifier rejects `BPF_JMP32 | BPF_JA` >> > - clang always generates `BPF_JMP | BPF_JA` >> >> Makes sense, thanks for the info. >> >> Do you know the precise pseudo-c assembly syntax to use for this >> instruction? > > In [1] Yonghong uses the following form: > > gotol +0xcd9b > > But it seems to be not specified in the documentation for the patch-set v3. I will use that syntax in binutils for now. > [1] https://reviews.llvm.org/D144829 > >> >> > Thanks, >> > Eduard >> > >> > [1] https://www.kernel.org/doc/html/latest/bpf/instruction-set.html#jump-instructions
