/*
 *	brlsft16.sfl	--- 16-Bit Barrel Shifter
 */

module brlsft16 {

input		shift;
input		right;
input		sign;
input		a<16>, b<4>;
output		y<16>;
instrin		enable;

instrself	n0, n1, n2, n3;
instrself	sr0, sr1, sr2, sr3;
instrself	sl0, sl1, sl2, sl3;
instrself	rr0, rr1, rr2, rr3;
instrself	rl0, rl1, rl2, rl3;

tmp		t0<16>, t1<16>, t2<16>;
tmp		s;

instruct enable par {
	s = a<15> & sign;
	alt {
	shift:
		alt {
		right:
			par {
				alt { b<3>: sr3(); else: n3(); }
				alt { b<2>: sr2(); else: n2(); }
				alt { b<1>: sr1(); else: n1(); }
				alt { b<0>: sr0(); else: n0(); }
			}
		else:
			par {
				alt { b<3>: sl3(); else: n3(); }
				alt { b<2>: sl2(); else: n2(); }
				alt { b<1>: sl1(); else: n1(); }
				alt { b<0>: sl0(); else: n0(); }
			}
		}
	else:
		alt {
		right:
			par {
				alt { b<3>: rr3(); else: n3(); }
				alt { b<2>: rr2(); else: n2(); }
				alt { b<1>: rr1(); else: n1(); }
				alt { b<0>: rr0(); else: n0(); }
			}
		else:
			par {
				alt { b<3>: rl3(); else: n3(); }
				alt { b<2>: rl2(); else: n2(); }
				alt { b<1>: rl1(); else: n1(); }
				alt { b<0>: rl0(); else: n0(); }
			}
		}
	}
}

instruct n3 y  = t2;
instruct n2 t2 = t1;
instruct n1 t1 = t0;
instruct n0 t0 = a;

instruct sr3 y  = s || s || s || s || s || s || s || s || t2<15:8>;
instruct sr2 t2 = s || s || s || s || t1<15:4>;
instruct sr1 t1 = s || s || t0<15:2>;
instruct sr0 t0 = s || a<15:1>;

instruct sl3 y  = t2< 7:0> || 0b00000000;
instruct sl2 t2 = t1<11:0> || 0b0000;
instruct sl1 t1 = t0<13:0> || 0b00;
instruct sl0 t0 =  a<14:0> || 0b0;

instruct rr3 y  = t2<7:0> || t2<15:8>;
instruct rr2 t2 = t1<3:0> || t1<15:4>;
instruct rr1 t1 = t0<1:0> || t0<15:2>;
instruct rr0 t0 =  a<0:0> ||  a<15:1>;

instruct rl3 y  = t2< 7:0> || t2<15: 8>;
instruct rl2 t2 = t1<11:0> || t1<15:12>;
instruct rl1 t1 = t0<13:0> || t0<15:14>;
instruct rl0 t0 =  a<14:0> ||  a<15:15>;

} /* brlsft16 */