PUTR, port?

From: Sean 'Captain Napalm' Conner <spc_at_conman.org>
Date: Sun Jan 18 22:24:39 2004

It was thus said that the Great Zane H. Healy once stated:
>
> >Any thought been given to porting PUTR to FreeBSD/Linux/Unix??? Was hoping
> >to use it but really don't want to install a dos partition on my Unix PC.
> >Other solutions out there?
> >
> >Jay
>

> As I recall it's pure x86 ASM code, porting it is likely to be rather
> difficult, which isn't to say impossible. Will it run under stuff like
> WinXP? Err... I guess it's kind of useless on such systems since you
> really need a 1.2MB 5 1/4" floppy, and if a system is running WinXP, the
> odds are it doesn't have one.

  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 ... )
Received on Sun Jan 18 2004 - 22:24:39 GMT