Re: [PATCH 8/9] x86/bpf: Convert asm comments to AT&T syntax

From: Josh Poimboeuf
Date: Thu Jun 13 2019 - 15:16:08 EST


On Thu, Jun 13, 2019 at 06:52:24PM +0000, Song Liu wrote:
> > @@ -403,11 +403,11 @@ static void emit_mov_imm64(u8 **pprog, u32 dst_reg,
> > * For emitting plain u32, where sign bit must not be
> > * propagated LLVM tends to load imm64 over mov32
> > * directly, so save couple of bytes by just doing
> > - * 'mov %eax, imm32' instead.
> > + * 'mov imm32, %eax' instead.
> > */
> > emit_mov_imm32(&prog, false, dst_reg, imm32_lo);
> > } else {
> > - /* movabsq %rax, imm64 */
> > + /* movabs imm64, %rax */
>
> ^^^^^ Should this be moveabsq?

Not for AT&T syntax:

~ $ cat test.S
movabs $0x1111111111111111, %rax
~ $ as test.S
~ $ objdump -d a.out

a.out: file format elf64-x86-64


Disassembly of section .text:

0000000000000000 <.text>:
0: 48 b8 11 11 11 11 11 movabs $0x1111111111111111,%rax
7: 11 11 11

--
Josh