> I want a program to run under MSDOS, compiled with BC++ 3.1,
 > which will dump all the accessible memory (ie from location 0
 > to location 1048576) to a file. I know how to do it if I was
 > dealing with a flat memory model on a decent operating
 > system, but not under MSDOS.


# include 
# include 
# include 
# include 
# include 

int
main (int argc, char * argv[])
{
    unsigned short seg = 0;
    char const * nam = (argc > 1) ? argv[1] : "dump.mem";
    int fd = open (nam, O_RDWR|O_CREAT|O_TRUNC|O_BINARY, S_IREAD|S_IWRITE);
    if (fd == -1)
    {
        fprintf(stderr, "Unable to create %s\n", nam);
        return 1;
    }
    do
    {
        asm {
            mov     bx,[fd]
            xor     dx,dx
            mov     cx,0x1000   /* write in 4K blocks */
            mov     ah,0x40
            push    ds
            mov     ds,[seg]
            int     0x21
            pop     ds
        }
        seg += 0x0100;
    }
    while (seg != 0);
    close (fd);
    return 0;
}

Apologies for the inline assembler, but I don't do much truely 'unportable'
stuff in C.  If I've got to "DOS" it, I'll usually use asm anyway
rather than fiddle with MK_FP's and so forth.  I guess it depends on what
you're used to, but I've got more flight hours in asm than in DOSish C. :-)
 This is also memory model independant.


  cheers,
  david

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