Sure, you can do it "directly" ("main" in this example). I would suggest you *do* use a linker (ld), unless you have some reason not to (ld knows "_start", unless told otherwise with "-e").
Best,
Frank
[map all]
;===========================================================================
bits 32
ORIGIN equ 8048000h
org ORIGIN
section .text
code_offset equ 0
code_addr:
;--------------------------- ELF header -----------------------------------
dd $464c457f,$00010101,0,0,$00030002,1,main,$34,0,0,$00200034,2,0
dd 1,code_offset,code_addr,code_addr,code_filez,code_memsz,5,4096
dd 1,data_offset,data_addr,data_addr,data_filez,data_memsz,6,4096
main:
;--------- your code goes here ------------------------------------------
;------------ constant data ---------------------------------
; (note that we're in .text, not .rdata)
align 4
;---------------------------------------------------------------------------
align 4
code_memsz equ $ - $$
code_filez equ code_memsz
data_addr equ (ORIGIN+code_memsz+4095)/4096*4096 + (code_filez % 4096)
data_offset equ code_filez
section .data vstart=data_addr
;------------ initialized data ------------------------------
;---------------------------------------------------------------------------
idat_memsz equ $ - $$
bss_addr equ data_addr + ($ - $$)
section .bss vstart=bss_addr
;--------------------------- uninitialized data ----------------------------
;---------------------------------------------------------------------------
udat_memsz equ $ - $$
data_memsz equ idat_memsz + udat_memsz
data_filez equ idat_memsz
;===========================================================================
