It was thus said that the Great Zane H. Healy once stated: One friend of mine, in the mid-90s, was hired to help port a MS-DOS application to Unix. Most of the application was already in C, but with a non-trivial portion in Assembly (mostly the I/O subsystem). My friend just basically translated the x86 code to C, pretty much as straight a translation as possible. So a routine like: get_current: push es push bx push cx push di mov es,[video_seg] mov bx,offset tank_sel mov cx,4 xor si,si get_c10: mov di,[bx+si] cmp byte ptr es:[di],_tank_ind je get_c20 inc si inc si loop get_c10 mov si,-1 get_c20: pop di pop cx pop bx pop es ret Would get translated as something like: int get_current(void) { char *es; int *bx; int cx; int si; int di; es = video_seg; bx = &tank_sel; cx = 4; si = 0; for ( ; cx ; cx--) { di = bx[si]; if (es[di] == TANK_IND) return(si); si++; } return(-1); } Not the greatest of C code, but it works and is a start in porting the code to other systems. -spc (Then later the code can be cleaned up ... )