[a3f@a3f-mbp snippets]$ gobjdump -hdr nasmbug.o

nasmbug.o:     file format mach-o-x86-64

Sections:
Idx Name          Size      VMA               LMA               File off  Algn
  0 .text         00000022  0000000000000000  0000000000000000  00000120  2**0
                  CONTENTS, ALLOC, LOAD, RELOC, CODE
  1 .data         00000003  0000000000000022  0000000000000022  00000142  2**0
                  CONTENTS, ALLOC, LOAD, DATA

Disassembly of section .text:

0000000000000000 <start>:
   0:   b8 04 00 00 02          mov    $0x2000004,%eax
   5:   bf 01 00 00 00          mov    $0x1,%edi
   a:   48 8d 35 fe 00 00 00    lea    0xfe(%rip),%rsi        # 10f <a+0xeb>
            d: BRANCH32 a
  11:   ba 02 00 00 00          mov    $0x2,%edx
  16:   0f 05                   syscall
  18:   b8 01 00 00 02          mov    $0x2000001,%eax
  1d:   48 31 ff                xor    %rdi,%rdi
  20:   0f 05                   syscall