Introduction

The .quad directive is used to define 64 bit numeric value(s). In similar way how .byte directive works. In this document, we will do some experiment for understanding .quad.

Test code

Create a file a.S with following content

.globl _start
_start:
mov x0,0xf5
.quad 0x123456789ABCDEF0,2,3
.align 5
mov x0,0xf4

Compile

Now using an arm cross compiler to compile above code

aarch64-linux-gnu-gcc -c a.S

This will generate an object file a.o

pandy@ubuntu:~/temp/asm_test$ file a.o
a.o: ELF 64-bit LSB relocatable, ARM aarch64, version 1 (SYSV), not stripped

Disassemble the code

Let’s check what is the generated code:

pandy@ubuntu:~/temp/asm_test$ aarch64-linux-gnu-objdump -d a.o

a.o:     file format elf64-littleaarch64


Disassembly of section .text:

0000000000000000 <_start>:
   0:   d2801ea0        mov     x0, #0xf5                       // #245
   4:   9abcdef0        .word   0x9abcdef0
   8:   12345678        .word   0x12345678
   c:   00000002        .word   0x00000002
  10:   00000000        .word   0x00000000
  14:   00000003        .word   0x00000003
  18:   00000000        .word   0x00000000
  1c:   d503201f        nop
  20:   d2801e80        mov     x0, #0xf4                       // #244