bits 32
section .payload ; could be .rodata/.text as well

payload_start:
incbin "exec_payload"
; MyExecTrailer
db 0xde,0xad,0xc0,0xde ; uint32_t marker[0]
db 0xca,0xfe,0xca,0xfe ; uint32_t marker[1]
dd 0x00000000,0x00000000,0x00000000,0x00000000 ; xorkey[XOR_KEYLEN]
dd $ - payload_start - 4 - 4 - 16 ; payload_size