@* Scheduling function for the lattice siever.
Copyright (C) 2002 Jens Franke, T. Kleinjung.
This file is part of gnfs4linux, distributed under the terms of the 
GNU General Public Licence and WITHOUT ANY WARRANTY.

You should have received a copy of the GNU General Public License along
with this program; see the file COPYING.  If not, write to the Free
Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA.
@(medsched.h@>=
u32_t *medsched(u32_t*,u32_t*,u32_t*,u32_t**,u32_t,u32_t);
u32_t *medsched_1(u32_t*,u32_t*,u32_t*,u32_t,unsigned char *,
                  unsigned char);

@
@c
#include <sys/types.h>
#include <limits.h>

#include "siever-config.h"
#include "medsched.h"
#include "../if.h"

#define L1_SIZE (1<<L1_BITS)
#define i_bits (I_bits-1)
#define n_i (1<<i_bits)

#define U16_SHIFT (CHAR_BIT*sizeof(u16_t))

u32_t *medsched0(u32_t*,u32_t*,u32_t*,u32_t**,u32_t);
u32_t *medsched0_1(u32_t*,u32_t*,u32_t*,unsigned char*,unsigned char);

u32_t *
medsched_1(ri,ij_ptr,ij_ptr_ub,ot,si,lo)
     u32_t *ri,*ij_ptr,*ij_ptr_ub,ot;
     unsigned char *si,lo;
{
  u32_t ij;
  u32_t ot_mask,ot_tester;

  if(ot!=0) {
    ot_tester=(ot&1)|((ot&2)<<(i_bits-1));
    ot_mask=n_i|1;
  } else return medsched0_1(ri,ij_ptr,ij_ptr_ub,si,lo);

  while ( ij_ptr < ij_ptr_ub) {
    u16_t a,b;

    a=n_i-(ri[0]&(n_i-1));
    b=n_i-(ri[1]&(n_i-1));
    if(ot == 0) ij=*ij_ptr;
    else @<Calculate first sieving event from |ri|@>@;
    while(ij<L1_SIZE) {
      u16_t i;

      si[ij]+=lo;

      i=ij&(n_i-1);
      if(i<b) ij+=ri[0];
      if(i>=a) ij+=ri[1];
    }
    ri+=2;
    *(ij_ptr++)=ij-L1_SIZE;
  }
  return ri;
}


u32_t *
medsched(ri,ij_ptr,ij_ptr_ub,sched_ptr,fbi_offs,ot)
     u32_t *ri,*ij_ptr,*ij_ptr_ub,**sched_ptr,fbi_offs,ot;
{
  u32_t ij;
  u32_t ot_mask,ot_tester;
  u32_t *sched;

  sched=*sched_ptr;

  if(ot!=0) {
    ot_tester=(ot&1)|((ot&2)<<(i_bits-1));
    ot_mask=n_i|1;
  } else return medsched0(ri,ij_ptr,ij_ptr_ub,sched_ptr,fbi_offs);

  while ( ij_ptr < ij_ptr_ub) {
    u16_t a,b;

    a=n_i-(ri[0]&(n_i-1));
    b=n_i-(ri[1]&(n_i-1));
    if(ot == 0) ij=*ij_ptr;
    else @<Calculate first sieving event from |ri|@>@;
    while(ij<L1_SIZE) {
      u16_t i;

      *(sched++)=(fbi_offs<<U16_SHIFT)|ij;
      i=ij&(n_i-1);
      if(i<b) ij+=ri[0];
      if(i>=a) ij+=ri[1];
    }
    ri+=2;
    *(ij_ptr++)=ij-L1_SIZE;
    fbi_offs++;
  }
  *sched_ptr=sched;
  return ri;
}

@
@<Calculate first sieving event from |ri|@>=
{
  ij=0;
  if( (ri[0]&ot_mask) == ot_tester ) ij=ri[0];
  else {
    if( (ri[1]&ot_mask) == (ot_tester^n_i) ) ij=ri[1];
    else {
      if((ri[0]&(n_i-1))<=(ri[1]&(n_i-1)) && ri[0]<=ri[1]) {
	/* This corresponds to the line
	   |if(b+c<=A && s<=t)| in recurrence6.w */
	if((ri[0]&(n_i-1))==(ri[1]&(n_i-1))) ij=ri[1]-ri[0];
	else ij=n_i;
	if(ot != 2)
	  Schlendrian("Exceptional situation for oddness type %u ?\n",
		      ot);
      }
      else ij=ri[0]+ri[1];
    }
  }
  ij=(ij+((~ot_tester)&n_i))/2;
}