Research V5 development

[unix-history] / usr / sys / dmr / mem.c

#
/*
*      Copyright 1973 Bell Telephone Laboratories Inc
*/

/*
*      Memory special file
*      minor device 0 is physical memory
*      minor device 1 is kernel memory
*      minor device 2 is EOF/RATHOLE
*/

#include "../param.h"
#include "../user.h"
#include "../conf.h"
#include "../seg.h"

mmread(dev)
{
       register c, bn, on;
       int a;

       if(dev.d_minor == 2)
               return;
       do {
               bn = lshift(u.u_offset, -6);
               on = u.u_offset[1] & 077;
               a = UISA->r[0];
               spl7();
               UISA->r[0] = bn;
               if(dev.d_minor == 1)
                       UISA->r[0] = KISA->r[(bn>>7)&07] + (bn & 0177);
               c = fubyte(on);
               UISA->r[0] = a;
               spl0();
       } while(u.u_error==0 && passc(c)>=0);
}

mmwrite(dev)
{
       register c, bn, on;
       int a;

       if(dev.d_minor == 2) {
               c = u.u_count;
               u.u_count = 0;
               u.u_base =+ c;
               dpadd(u.u_offset, c);
               return;
       }
       for(;;) {
               bn = lshift(u.u_offset, -6);
               on = u.u_offset[1] & 077;
               if ((c=cpass())<0 || u.u_error!=0)
                       break;
               a = UISA->r[0];
               spl7();
               UISA->r[0] = bn;
               if(dev.d_minor == 1)
                       UISA->r[0] = KISA->r[(bn>>7)&07] + (bn & 0177);
               subyte(on, c);
               UISA->r[0] = a;
               spl0();
       }
}