Re: [RFC PATCH v1 2/5] tools/nolibc: x86-64: Use `rep stosb` for `memset()`

[Ammar Faizi]

On Wed, Aug 30, 2023 at 05:23:22PM +0200, Willy Tarreau wrote:
> Then "xchg %esi, %eax" is just one byte with no memory access ;-)

Perfect!

Now I got this, shorter than "movl %esi, %eax":
```
0000000000001500 <memset>:
    1500: 96          xchg   %eax,%esi
    1501: 48 89 d1    mov    %rdx,%rcx
    1504: 57          push   %rdi
    1505: f3 aa       rep stos %al,%es:(%rdi)
    1507: 58          pop    %rax
    1508: c3          ret
```

Unfortunately, the xchg trick doesn't yield smaller machine code for
%rdx, %rcx. Lol.

-- 
Ammar Faizi