; ELF header
; e_ident: u128
; Magic number: 0x7f454c46 = "\x7fELF"
7f 45 4c 46
; EI_CLASS: u8 = ELFCLASS64
02
; EI_DATA: u8 = ELFDATA2LSB
01
; EI_VERSION: u8 = EV_CURRENT
01
; EI_OSABI: u8 = ELFOSABI_NONE
00
; EI_ABIVERSION: u8 = 0
00
; EI_PAD: [u8; 7]
00 00 00 00 00 00 00
; e_type: u16 = E_EXEC
02 00
; e_machine: u16 = EM_X86_64
3e 00
; e_version: u32 = EV_CURRENT
01 00 00 00
; e_entry: u64 = 0x400078 + 0x5c
d4 00 40 00 00 00 00 00
; e_phoff: u64 = 0x40
40 00 00 00 00 00 00 00
; e_shoff: u64 = 0x0
00 00 00 00 00 00 00 00
; e_flags: u32 = 0
00 00 00 00
; e_ehsize: u16 = 64
40 00
; e_phentsize: u16 = 56
38 00
; e_phnum: u16 = 1
01 00
; e_shentsize: u16 = 0
00 00
; e_shnum: u16 = 0
00 00
; e_shstrndx: u16 = 0
00 00
; End of ELF header
;
; Program header
; p_type: u32 = PT_LOAD
01 00 00 00
; p_flags: u32 = PF_R | PF_X
05 00 00 00
; p_offset: u64 = 0
00 00 00 00 00 00 00 00
; p_vaddr: u64 = 0x400000
00 00 40 00 00 00 00 00
; p_paddr: u64 = 0x0
00 00 00 00 00 00 00 00
; p_filesz: u64 = 0x167
ef 01 00 00 00 00 00 00
; p_memsz: u64 = 0x167
ef 01 00 00 00 00 00 00
; p_align: u64 = 0x1000
00 10 00 00 00 00 00 00
; End of program header
;
; @die: +0
; mov rax, 60 (exit)
b8 3c 00 00 00
; mov rdi, 0 (exit code)
bf 00 00 00 00
; syscall
0f 05
; ret
c3
;
; @fopen:
; mov rax, 2 (sys_open)
b8 02 00 00 00
; mov rsi, 0
be 00 00 00 00
; mov rdx, 0
ba 00 00 00 00
; syscall
0f 05
; ret
c3
;
; fopen_write:
; mov rax, 2 (sys_open)
b8 02 00 00 00
; mov rsi, 0x241 (O_WRONLY | O_CREAT | O_TRUNC)
be 41 02 00 00
; mov rdx, 0o644 (file mode)
ba a4 01 00 00
; syscall
0f 05
; ret
c3
;
; @fstat:
;  mov rax, 5 (sys_fstat)
b8 05 00 00 00
;  syscall
0f 05
;  ret
c3
;
; @fsize:
;  push rdi
57
;  push rsi
56
;  call 'fstat
e8 f1 ff ff ff
;  pop rsi
5e
;  pop rdi
5f
;  mov rax, [rsi+48] (st_size)
48 8b 46 30
;  ret
c3
;
; @memcpy:
;  test rdx, rdx
48 85 d2
;  jz 'memcpy_exit
74 0f
;  mov al, byte [rdi]
8a 07
;  mov byte [rsi], al
88 06
;  inc rsi
48 ff c6
;  inc rdi
48 ff c7
;  dec rdx
48 ff ca
;  jmp 'memcpy
eb ec
; @memcpy_exit:
c3
;
; @_start:
;  mov eax, dword [rsp] (argc)
8b 04 24
;  lea rbx, [rsp+8] (argv)
48 8d 5c 24 08
;  sub rsp, 0x4000
48 81 ec 00 40 00 00
;  mov r15, rsp
49 89 e7
;  mov dword [r15+0x1010], eax (store argc)
41 89 87 10 10 00 00
;  mov qword [r15+0x1018], rbx (store argv)
49 89 9f 18 10 00 00
;  cmp eax, 3
83 f8 03
;  jl 'die
0f 8c 7b ff ff ff
;
;  mov rdi, qword [r15+0x1018] (argv)
49 8b bf 18 10 00 00
;  add rdi, 8 (argv[1])
48 83 c7 08
;  mov rdi, [rdi] (argv[1])
48 8b 3f
;  call 'fopen_write
e8 87 ff ff ff
;
;  mov dword [r15+0x101c], eax (store file descriptor)
41 89 87 0c 10 00 00
;  mov rdi, qword [r15+0x1018] (argv)
49 8b bf 18 10 00 00
;  add rdi, 16 (argv[2])
48 83 c7 10
;  mov rdi, [rdi] (argv[2])
48 8b 3f
;  call 'fopen
e8 5b ff ff ff
;
;  mov dword [r15+0x1008], eax (store file descriptor)
41 89 87 08 10 00 00
;  mov edi, eax (fd)
89 c7
;  lea rsi, [r15]
49 8d 37
;  call 'fsize
e8 76 ff ff ff
;
;  mov dword [r15+0x1004], eax (store file size)
41 89 87 04 10 00 00
;  mov edi, 0x400000
bf 00 00 40 00
;  mov rsi, r15
4c 89 fe
;  mov edx, 0x40 (size)
ba 40 00 00 00
;  call 'memcpy
e8 6b ff ff ff
;
;  mov edi, 0x400040
bf 40 00 40 00
;  lea rsi, [r15+0x40]
49 8d 77 40
;  mov edx, 0x38 (size)
ba 38 00 00 00
;  call 'memcpy
e8 58 ff ff ff
;
;  mov eax, 0x78
b8 78 00 00 00
;  add eax, dword [r15+0x1004] (file size)
41 03 87 04 10 00 00
;  mov dword [r15+0x60], eax (store file end)
41 89 47 60
;  mov dword [r15+0x68], eax (store file end)
41 89 47 68
;
;  sub rax, 5
48 83 e8 05
; add rax, 0x400000
48 05 00 00 40 00
;  mov dword [r15+0x18], eax (store file end - 5)
41 89 47 18
;
;  mov edi, dword [r15+0x100c] (fd)
41 8b bf 0c 10 00 00
;  mov rsi, r15
4c 89 fe
;  mov edx, 0x78 (size)
ba 78 00 00 00
;  mov eax, 1 (sys_write)
b8 01 00 00 00
;  syscall
0f 05
; @write_loop:
;  mov edi, dword [r15+0x1008] (fd)
41 8b bf 08 10 00 00
;  mov rsi, r15
4c 89 fe
;  mov edx, 0x1000 (size)
ba 00 10 00 00
;  mov eax, 0 (sys_read)
b8 00 00 00 00
;  syscall
0f 05
;  test rax, rax
48 85 c0
;  jle 'die
0f 8e ba fe ff ff
;
;  mov dword [r15+0x1000], eax (store bytes read)
41 89 87 00 10 00 00
;  mov edi, dword [r15+0x100c] (fd)
41 8b bf 0c 10 00 00
;  mov rsi, r15
4c 89 fe
;  mov edx, dword [r15+0x1000] (bytes read)
41 8b 97 00 10 00 00
;  mov eax, 1 (sys_write)
b8 01 00 00 00
;  syscall
0f 05
;  cmp dword [r15+0x1000], 0x1000
41 81 bf 00 10 00 00 00 10 00 00
;  jz 'write_loop
74 b5
;  call 'die
e8 89 fe ff ff
; end