Nonsensical disassembly of ARMv8 instructions

[noloader]

Raspberry Pi 3 uses an ARMv8 processor. The machine can consume ARMv8 instructions, even though an ARMv7-based OS is provided. The sample program below with hand crafted ARMv8 instructions executes successfully.

However, disassembling fails:

$ gcc -g3 -O0 -march=armv7-a -mfpu=neon test.cc -c
$ objdump -d test.o

test.o:     file format elf32-littlearm

Disassembly of section .text:

00000000 <main>:
   0:   e52db004    push    {fp}        ; (str fp, [sp, #-4]!)
   4:   e28db000    add fp, sp, #0
   8:   e24dd00c    sub sp, sp, #12
   c:   e50b0008    str r0, [fp, #-8]
  10:   e50b100c    str r1, [fp, #-12]
  14:   0058c11a    .word   0x0058c11a
  18:   0054c11a    .word   0x0054c11a
  1c:   0050c11a    .word   0x0050c11a
  20:   00e0e10e    .word   0x00e0e10e
  24:   00e0e14e    .word   0x00e0e14e
  28:   2048284e    .word   0x2048284e
  2c:   2058284e    .word   0x2058284e
  30:   2000025e    .word   0x2000025e
  34:   2020025e    .word   0x2020025e
  38:   2030025e    .word   0x2030025e
  3c:   e3a03000    mov r3, #0
  40:   e1a00003    mov r0, r3
  44:   e24bd000    sub sp, fp, #0
  48:   e49db004    pop {fp}        ; (ldr fp, [sp], #4)
  4c:   e12fff1e    bx  lr

---

This can be compiled with gcc -g3 -O0 -march=armv7-a -mfpu=neon test.cc.

$ cat test.cc
#include <arm_neon.h>
int main(int argc, char* argv[])
{
  __asm__ __volatile__
    (
     ".code 32"

     // CRC using word
     ".byte 0x1a, 0xc1, 0x58, 0x00;\n"
     // CRC using half word
     ".byte 0x1a, 0xc1, 0x54, 0x00;\n"
     // CRC using byte
     ".byte 0x1a, 0xc1, 0x50, 0x00;\n"
     // PMULL
     ".byte 0x0e, 0xe1, 0xe0, 0x00;\n"
     // PMULL2
     ".byte 0x4e, 0xe1, 0xe0, 0x00;\n"
     // AES (aese)
     ".byte 0x4e, 0x28, 0x48, 0x20;\n"
     // AES (aesd)
     ".byte 0x4e, 0x28, 0x58, 0x20;\n"
     // SHA1 (sha1c)
     ".byte 0x5e, 0x02, 0x00, 0x20;\n"
     // SHA1 (sha1m)
     ".byte 0x5e, 0x02, 0x20, 0x20;\n"
     // SHA1 (sha1p)
     ".byte 0x5e, 0x02, 0x30, 0x20;\n"
     :
     :
     : "cc", "d0", "d1", "d2", "q0", "q1", "q2"
    );

  return 0;
}

[noloader]

I'm going to close this. The toolchain has bigger problems than disassemblies. Its not worth the dev cycles at the moment.