vi_lerp_csa.v 3.39 KB
////////////////////////////////////////////////////////////////////////
//
// Project Reality
//
// module:	vi_lerp_csa
// description:	Carry save adder tree for lerp for video interface.
//		10 partial products.
//
// designer:	Phil Gossett
// date:	10/23/94
//
////////////////////////////////////////////////////////////////////////

// $Id: vi_lerp_csa.v,v 1.1 2002/05/21 23:55:45 berndt Exp $

module vi_lerp_csa (a, p0p, p1p, p2p, p3p, p4p, p5p, p6p, p7p, c, mp);

input [4:0] a;
input [5:0] p0p;
input [5:0] p1p;
input [5:0] p2p;
input [5:0] p3p;
input [5:0] p4p;
input [5:0] p5p;
input [5:0] p6p;
input [5:0] p7p;
input [7:0] c;

output [7:0] mp;

wire [5:0] sa;		// intermediate carry save adder sums and carrys
wire [5:0] ca;
wire [7:0] sb;
wire [5:0] cb;
wire [6:0] sc;
wire [7:0] cc;
wire [7:0] sd;
wire [5:0] cd;
wire [7:0] se;
wire [6:0] ce;
wire [8:0] sf;
wire [7:0] cf;
wire [10:0] sg;
wire [7:0] cg;
wire [9:0] sh;
wire [9:0] ch;
wire [9:0] si;

assign sa[5] = p1p[5];
vi_lerp_csa_ha1  sag	(.a(p0p[5]),
			 .b(p1p[4]),
			 .s(sa[4]),	.co(ca[5]));
vi_lerp_csa_fa4  saf	(.a(a[4:1]),
			 .b(p0p[4:1]),
			 .ci(p1p[3:0]),
			 .s(sa[3:0]),	.co(ca[4:1]));
vi_lerp_csa_haco sah	(.a(a[0]),
			 .b(p0p[0]),	.co(ca[0]));

assign sb[7] = p3p[5];
vi_lerp_csa_ha1  sbg	(.a(p3p[4]),
			 .b(p2p[5]),
			 .s(sb[6]),	.co(cb[5]));
vi_lerp_csa_fa4  sbf	(.a(p3p[3:0]),
			 .b(p2p[4:1]),
			 .ci(ca[5:2]),
			 .s(sb[5:2]),	.co(cb[4:1]));
vi_lerp_csa_ha1  sbh	(.a(p2p[0]),
			 .b(ca[1]),
			 .s(sb[1]),	.co(cb[0]));
assign sb[0] = ca[0];

vi_lerp_csa_ha2  scg	(.a(cb[5:4]),
			 .b(sb[7:6]),
			 .s(sc[6:5]),	.co(cc[7:6]));
vi_lerp_csa_fa4  scf	(.a(sa[5:2]),
			 .b(cb[3:0]),
			 .ci(sb[5:2]),
			 .s(sc[4:1]),	.co(cc[5:2]));
vi_lerp_csa_ha1  sch	(.a(sa[1]),
			 .b(sb[1]),
			 .s(sc[0]),	.co(cc[1]));
vi_lerp_csa_haco sce	(.a(sa[0]),
			 .b(sb[0]),	.co(cc[0]));

assign sd[7] = p6p[5];
vi_lerp_csa_ha1  sdg	(.a(p5p[5]),
			 .b(p6p[4]),
			 .s(sd[6]),	.co(cd[5]));
vi_lerp_csa_fa5  sdf	(.a(p4p[5:1]),
			 .b(p5p[4:0]),
			 .ci({p6p[3:0],1'b1}),
			 .s(sd[5:1]),	.co(cd[4:0]));
assign sd[0] = p4p[0];

vi_lerp_csa_haso seg	(.a(c[7]),
			 .b(p7p[5]),
			 .s(se[7]));
vi_lerp_csa_fa6  sef	(.a(c[6:1]),
			 .b({p7p[4:0],1'b1}),
			 .ci(cd[5:0]),
			 .s(se[6:1]),	.co(ce[6:1]));
assign se[0] = ~c[0];
assign ce[0] = c[0];

vi_lerp_csa_haso sfg	(.a(ce[6]),
			 .b(se[7]),
			 .s(sf[8]));
vi_lerp_csa_fa6  sff	(.a(sd[7:2]),
			 .b(ce[5:0]),
			 .ci(se[6:1]),
			 .s(sf[7:2]),	.co(cf[7:2]));
vi_lerp_csa_ha2  sfh	(.a(sd[1:0]),
			 .b({se[0],1'b1}),
			 .s(sf[1:0]),	.co(cf[1:0]));

vi_lerp_csa_haso sgi	(.a(cf[7]),
			 .b(sf[8]),
			 .s(sg[10]));
vi_lerp_csa_ha2  sgg	(.a(cf[6:5]),
			 .b(sf[7:6]),
			 .s(sg[9:8]),	.co(cg[7:6]));
vi_lerp_csa_fa5  sgf	(.a(cc[7:3]),
			 .b(cf[4:0]),
			 .ci(sf[5:1]),
			 .s(sg[7:3]),	.co(cg[5:1]));
vi_lerp_csa_ha1  sgh	(.a(cc[2]),
			 .b(sf[0]),
			 .s(sg[2]),	.co(cg[0]));
assign sg[1:0] = cc[1:0];

vi_lerp_csa_haso shi	(.a(cg[7]),
			 .b(sg[10]),
			 .s(sh[9]));
vi_lerp_csa_ha3  shg	(.a(cg[6:4]),
			 .b(sg[9:7]),
			 .s(sh[8:6]),	.co(ch[9:7]));
vi_lerp_csa_fa4  shf	(.a(sc[6:3]),
			 .b(cg[3:0]),
			 .ci(sg[6:3]),
			 .s(sh[5:2]),	.co(ch[6:3]));
vi_lerp_csa_ha2  shh	(.a(sc[2:1]),
			 .b(sg[2:1]),
			 .s(sh[1:0]),	.co(ch[2:1]));
vi_lerp_csa_haco she	(.a(sc[0]),
			 .b(sg[0]),	.co(ch[0]));

vi_lerp_csa_add10 mpa	(.b(sh[9:0]),	// final carry-propagating adder
			 .a(ch[9:0]),
			 .s(si[9:0]));
assign mp = si[9:2];

endmodule // vi_lerp_csa