| Line 1... |
Line 1... |
// ============================================================================
|
// ============================================================================
|
// __
|
// __
|
// \\__/ o\ (C) 2019 Robert Finch, Waterloo
|
// \\__/ o\ (C) 2006-2019 Robert Finch, Waterloo
|
// \ __ / All rights reserved.
|
// \ __ / All rights reserved.
|
// \/_// robfinch@finitron.ca
|
// \/_// robfinch@finitron.ca
|
// ||
|
// ||
|
//
|
//
|
//
|
//
|
| Line 19... |
Line 19... |
// You should have received a copy of the GNU General Public License
|
// You should have received a copy of the GNU General Public License
|
// along with this program. If not, see .
|
// along with this program. If not, see .
|
//
|
//
|
// ============================================================================
|
// ============================================================================
|
//
|
//
|
module fpRes(clk, a, o);
|
module fpRes(clk, ce, a, o);
|
parameter WID = 128;
|
parameter WID = 128;
|
localparam MSB = WID-1;
|
`include "fpSize.sv"
|
localparam EMSB = WID==128 ? 14 :
|
|
WID==96 ? 14 :
|
|
WID==80 ? 14 :
|
|
WID==64 ? 10 :
|
|
WID==52 ? 10 :
|
|
WID==48 ? 11 :
|
|
WID==44 ? 10 :
|
|
WID==42 ? 10 :
|
|
WID==40 ? 9 :
|
|
WID==32 ? 7 :
|
|
WID==24 ? 6 : 4;
|
|
localparam FMSB = WID==128 ? 111 :
|
|
WID==96 ? 79 :
|
|
WID==80 ? 63 :
|
|
WID==64 ? 51 :
|
|
WID==52 ? 39 :
|
|
WID==48 ? 34 :
|
|
WID==44 ? 31 :
|
|
WID==42 ? 29 :
|
|
WID==40 ? 28 :
|
|
WID==32 ? 22 :
|
|
WID==24 ? 15 : 9;
|
|
input clk;
|
input clk;
|
|
input ce;
|
input [WID-1:0] a;
|
input [WID-1:0] a;
|
output [WID-1:0] o;
|
output [WID-1:0] o;
|
|
|
// This table encodes two endpoints k0, k1 of a piece-wise linear
|
// This table encodes two endpoints k0, k1 of a piece-wise linear
|
// approximation to the reciprocal in the range [1.0,2.0).
|
// approximation to the reciprocal in the range [1.0,2.0).
|
| Line 1093... |
Line 1072... |
wire [EMSB:0] exp3;
|
wire [EMSB:0] exp3;
|
wire [9:0] index = ma[FMSB:FMSB-9];
|
wire [9:0] index = ma[FMSB:FMSB-9];
|
reg [9:0] indexr;
|
reg [9:0] indexr;
|
reg [15:0] k0, k1;
|
reg [15:0] k0, k1;
|
always @(posedge clk)
|
always @(posedge clk)
|
indexr <= index;
|
if(ce) indexr <= index;
|
always @(posedge clk)
|
always @(posedge clk)
|
k0 <= k01[indexr][31:16];
|
if(ce) k0 <= k01[indexr][31:16];
|
always @(posedge clk)
|
always @(posedge clk)
|
k1 <= k01[indexr][15: 0];
|
if(ce) k1 <= k01[indexr][15: 0];
|
delay3 #(1) u2 (.clk(clk), .ce(1'b1), .i(sa), .o(sa3));
|
delay3 #(1) u2 (.clk(clk), .ce(1'b1), .i(sa), .o(sa3));
|
delay3 #(EMSB+1) u3 (.clk(clk), .ce(1'b1), .i(exp), .o(exp3));
|
delay3 #(EMSB+1) u3 (.clk(clk), .ce(1'b1), .i(exp), .o(exp3));
|
wire [15:0] eps = ma[FMSB-10:FMSB-10-15];
|
wire [15:0] eps = ma[FMSB-10:FMSB-10-15];
|
wire [31:0] p = k1 * eps;
|
wire [31:0] p = k1 * eps;
|
reg [15:0] r0;
|
reg [15:0] r0;
|
always @(posedge clk)
|
always @(posedge clk)
|
r0 <= k0 - (p >> 26);
|
if(ce) r0 <= k0 - (p >> 26);
|
assign o = {sa3,exp3,r0[14:0],{FMSB+2-16{1'b0}}};
|
assign o = {sa3,exp3,r0[14:0],{FMSB+2-16{1'b0}}};
|
|
|
always @*
|
always @*
|
if (WID < 48) begin
|
if (WID < 48) begin
|
$display("Reciprocal estimate needs at least 48 bit floats.");
|
$display("Reciprocal estimate needs at least 48 bit floats.");
|
