text: #include "a.h"
  
  /*
   * Section 3 - page control (mostly irrelevant).
   */
  
  /* page offset */
  void
  po(int o)
  {
  	nr(L(".o0"), getnr(L(".o")));
  	nr(L(".o"), o);
  }
  
  void
  r_po(int argc, Rune **argv)
  {
  	if(argc == 1){
  		po(getnr(L(".o0")));
  		return;
  	}
  	if(argv[1][0] == '+')
  		po(getnr(L(".o"))+evalscale(argv[1]+1, 'v'));
  	else if(argv[1][0] == '-')
  		po(getnr(L(".o"))-evalscale(argv[1]+1, 'v'));
  	else
  		po(evalscale(argv[1], 'v'));
  }
  
  /* .ne - need vertical space */
  /* .mk - mark current vertical place */
  /* .rt - return upward */
  
  void
  t3init(void)
  {
  	nr(L(".o"), eval(L("1i")));
  	nr(L(".o0"), eval(L("1i")));
  	nr(L(".p"), eval(L("11i")));
  
  	addreq(L("pl"), r_warn, -1);
  	addreq(L("bp"), r_nop, -1);
  	addreq(L("pn"), r_warn, -1);
  	addreq(L("po"), r_po, -1);
  	addreq(L("ne"), r_nop, -1);
  	addreq(L("mk"), r_nop, -1);
  	addreq(L("rt"), r_warn, -1);
  }
  