On Tue, 2023-08-15 at 11:01 +0800, Leon Hwang wrote: [...] > a) Initial value of RAX is in emit_prologue(). > if (!ebpf_from_cbpf) { > if (tail_call_reachable && !is_subprog) > /* When it's the entry of the whole > * tailcall context, zeroing the RAX > * means init tail_call_cnt. > */ > EMIT2(0x31, 0xC0); /* xor eax, eax */ > else > // Keep the same asm layout. > EMIT2(0x66, 0x90); /* nop2 */ > } > I'd like to add this comment to emit_prologue(). Got it, thank you. [...]