# SABR
# multiply two unsigned binary numbers or factor number

Sym { u 0 1 }

# x2 x1 x0
# y2 y1 y0
# 
# if y0:  0   0   x2  x1  x0
# if y1:  0   x2  x1  x0  0
# if y2:  x2  x1  x0  0   0

# built similar to an alu
Board {
	x2 x1 x0;			# multiply numbers
	y2 y1 y0;

	t04 t03 t02 t01 t00;		# carrys
	f04 f03 f02 f01 f00;		# if y0:  0   0   x2  x1  x0
	s04 s03 s02 s01 s00;		# if y1:  0   x2  x1  x0  0
	
	t05
	t14 t13 t12 t11 t10;		# carrys
	f14 f13 f12 f11 f10;		# output of last
	s14 s13 s12 s11 s10;		# if y2:  x2  x1  x0  0   0
	
	t15
	f24 f23 f22 f21 f20;		# final output
}

# 3 * 3 = 9
# 1 0 0 1
Req Board {

	? ? ?;
	? ? ?;
	
	? ? ? ? 0;
	0 0 ? ? ?;
	0 ? ? ? 0;
	
	?
	? ? ? ? 0;
	? ? ? ? ?;
	? ? ? 0 0;
	
	0
	0 1 0 0 1;	
}

# equivalent to multiply single bottom row bit by top row
# this is the same as standard grade school multiplication, but in base 2
Opt Link1 { set2 set1 set0; set2 set1 set0; 1; }
Opt Link1 {    ?    ?    ?;    0    0    0; 0; }

# link
DesObj Link1 { x2 x1 x0; f02 f01 f00; y0; }
DesObj Link1 { x2 x1 x0; s03 s02 s01; y1; }
DesObj Link1 { x2 x1 x0; s14 s13 s12; y2; }

# add
Opt Add{ 0 0 0; 0 0; }

Opt Add{ 0 0 1; 0 1; }
Opt Add{ 0 1 0; 0 1; }
Opt Add{ 1 0 0; 0 1; }

Opt Add{ 0 1 1; 1 0; }
Opt Add{ 1 0 1; 1 0; }
Opt Add{ 1 1 0; 1 0; }

Opt Add{ 1 1 1; 1 1; }

# describe
DesObj Add{ t00 f00 s00; t01 f10; }
DesObj Add{ t01 f01 s01; t02 f11; }
DesObj Add{ t02 f02 s02; t03 f12; }
DesObj Add{ t03 f03 s03; t04 f13; }
DesObj Add{ t04 f04 s04; t05 f14; }

DesObj Add{ t10 f10 s10; t11 f20; }
DesObj Add{ t11 f11 s11; t12 f21; }
DesObj Add{ t12 f12 s12; t13 f22; }
DesObj Add{ t13 f13 s13; t14 f23; }
DesObj Add{ t14 f14 s14; t15 f24; }