A self-replicating 64bit assembly program for OS X. Save as g and run with "as g -o g.o; ld g.o -e _m; ./a.out"

Quine ASM

.section __DATA,__data                    # OSX specific form of ".section data"
SOURCE:                                   # .incbin copies files into applications byte-for-byte
   .incbin "g"                            # so this is loading the source's bytes into a var called SOURCE
SIZE = . - SOURCE                         # . here points to the byte after SOURCE in memory
                                          # so . - SOURCE returns the length of SOURCE in mem
.section __TEXT,__text
.globl _main                              # entry point. also OSX needs _ before the function 
_main:
   movl $0x2000004, %eax                  # x64 needs to pad syscalls w 0x2000000 so 4 is sys_write
   movl $1, %edi                          # with sys_write in eax, moving 1 into edi says write to console
   movq SOURCE@GOTPCREL(%rip),%rsi        # str's in the Global Offset Table (GOT) and we access thru %rip
   movq $SIZE, %rdx                       # move the length to read into %rdx (the next sequential register)
   syscall                                # execute eax with edi as return code. (sys_write to console)
 
   movl $0, %ebx                          # set return code to 0
   movl $0x2000001, %eax                  # sys_exit
   syscall                                # execute exit with a success return code