In re-reading the instruction-set.rst changes for sign extensions, there is one ambiguity regarding BPF_ALU | BPF_MOVSX with offset = 32. Is it: a) Undefined (not a permitted instruction), or b) Defined as being synonymous with BPF_ALU | BPF_MOV? The table implies (b) when it says: > BPF_MOVSX 0xb0 8/16/32 dst = (s8,s16,s32)src But the following text could be interpreted as (): > ``BPF_ALU | BPF_MOVSX`` :term:`sign extends<Sign Extend>` 8-bit and 16-bit operands into 32 > bit operands, and zeroes the remaining upper 32 bits. There's no reason I can think of to use it, given it's synonymous but if given a BPF program that uses it, should it be rejected by a verifier/disassembler/etc.? Or treated as valid? Dave
