.sect .text; .sect .rom; .sect .data; .sect .bss .define _fork, _par_uid .sect .bss .comm _par_uid, 4 .sect .text _fork: mov ax,2 callf 0x7:0x0 jb 1f and dx,dx jne 2f ret 1: jmp cerror 2: mov (_par_uid),ax xor ax,ax ret