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//     \/_//     robfinch@finitron.ca
//     \/_//     robfinch@finitron.ca
//       ||
//       ||
//
//
//      fpMultiply.v
//      fpMultiply.v
//              - floating point multiplier
//              - floating point multiplier
//              - two cycle latency
//              - two cycle latency minimum (latency depends on precision)
//              - can issue every clock cycle
//              - can issue every clock cycle
//              - parameterized width
//              - parameterized width
//              - IEEE 754 representation
//              - IEEE 754 representation
//
//
//
//
// This source file is free software: you can redistribute it and/or modify
// BSD 3-Clause License
// it under the terms of the GNU Lesser General Public License as published
// Redistribution and use in source and binary forms, with or without
// by the Free Software Foundation, either version 3 of the License, or
// modification, are permitted provided that the following conditions are met:
// (at your option) any later version.
//
//
// 1. Redistributions of source code must retain the above copyright notice, this
// This source file is distributed in the hope that it will be useful,
//    list of conditions and the following disclaimer.
// but WITHOUT ANY WARRANTY; without even the implied warranty of
//
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// 2. Redistributions in binary form must reproduce the above copyright notice,
// GNU General Public License for more details.
//    this list of conditions and the following disclaimer in the documentation
 
//    and/or other materials provided with the distribution.
 
//
 
// 3. Neither the name of the copyright holder nor the names of its
 
//    contributors may be used to endorse or promote products derived from
 
//    this software without specific prior written permission.
 
//
 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
//
// You should have received a copy of the GNU General Public License
 
// along with this program.  If not, see .
 
//
//
//      Floating Point Multiplier / Divider
//      Floating Point Multiplier
//
//
//      This multiplier/divider handles denormalized numbers.
//      This multiplier handles denormalized numbers.
//      The output format is of an internal expanded representation
//      The output format is of an internal expanded representation
//      in preparation to be fed into a normalization unit, then
//      in preparation to be fed into a normalization unit, then
//      rounding. Basically, it's the same as the regular format
//      rounding. Basically, it's the same as the regular format
//      except the mantissa is doubled in size, the leading two
//      except the mantissa is doubled in size, the leading two
//      bits of which are assumed to be whole bits.
//      bits of which are assumed to be whole bits.
Line 40... Line 54...
//
//
//      Properties:
//      Properties:
//      +-inf * +-inf = -+inf   (this is handled by exOver)
//      +-inf * +-inf = -+inf   (this is handled by exOver)
//      +-inf * 0     = QNaN
//      +-inf * 0     = QNaN
//
//
//      1 sign number
 
//      8 exponent
 
//      48 mantissa
 
//
 
// ============================================================================
// ============================================================================
 
 
import fp::*;
import fp::*;
 
 
module fpMultiply(clk, ce, a, b, o, sign_exe, inf, overflow, underflow);
module fpMultiply(clk, ce, a, b, o, sign_exe, inf, overflow, underflow);
Line 57... Line 67...
output [EX:0] o;
output [EX:0] o;
output sign_exe;
output sign_exe;
output inf;
output inf;
output overflow;
output overflow;
output underflow;
output underflow;
 
parameter DELAY =
 
  (FPWID == 128 ? 17 :
 
  FPWID == 80 ? 17 :
 
  FPWID == 64 ? 13 :
 
  FPWID == 40 ? 8 :
 
  FPWID == 32 ? 2 :
 
  FPWID == 16 ? 2 : 2);
 
 
reg [EMSB:0] xo1;               // extra bit for sign
reg [EMSB:0] xo1;               // extra bit for sign
reg [FX:0] mo1;
reg [FX:0] mo1;
 
 
// constants
// constants
Line 85... Line 102...
wire aNan, bNan, aNan1, bNan1;
wire aNan, bNan, aNan1, bNan1;
wire az, bz;
wire az, bz;
wire aInf, bInf, aInf1, bInf1;
wire aInf, bInf, aInf1, bInf1;
 
 
 
 
// -----------------------------------------------------------
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// First clock
// Clock #1
// - decode the input operands
// - decode the input operands
// - derive basic information
// - derive basic information
// - calculate exponent
// - calculate exponent
// - calculate fraction
// - calculate fraction
 
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
 
 
// -----------------------------------------------------------
 
// First clock
// -----------------------------------------------------------
// -----------------------------------------------------------
 
 
fpDecomp u1a (.i(a), .sgn(sa), .exp(xa), .fract(fracta), .xz(a_dn), .vz(az), .inf(aInf), .nan(aNan) );
fpDecomp u1a (.i(a), .sgn(sa), .exp(xa), .fract(fracta), .xz(a_dn), .vz(az), .inf(aInf), .nan(aNan) );
fpDecomp u1b (.i(b), .sgn(sb), .exp(xb), .fract(fractb), .xz(b_dn), .vz(bz), .inf(bInf), .nan(bNan) );
fpDecomp u1b (.i(b), .sgn(sb), .exp(xb), .fract(fractb), .xz(b_dn), .vz(bz), .inf(bInf), .nan(bNan) );
 
 
// Compute the sum of the exponents.
// Compute the sum of the exponents.
// correct the exponent for denormalized operands
// correct the exponent for denormalized operands
// adjust the sum by the exponent offset (subtract 127)
// adjust the sum by the exponent offset (subtract 127)
// mul: ex1 = xa + xb,  result should always be < 1ffh
// mul: ex1 = xa + xb,  result should always be < 1ffh
 
`ifdef SUPPORT_DENORMALS
assign ex1 = (az|bz) ? 0 : (xa|a_dn) + (xb|b_dn) - bias;
assign ex1 = (az|bz) ? 0 : (xa|a_dn) + (xb|b_dn) - bias;
 
`else
 
assign ex1 = (az|bz) ? 0 : xa + xb - bias;
 
`endif
 
 
generate
generate
if (FPWID==80) begin
if (FPWID==128) begin
reg [31:0] p00,p01,p02,p03;
  wire [255:0] fractoo;
reg [31:0] p10,p11,p12,p13;
  mult128x128 umul1 (.clk(clk), .ce(ce), .a({16'b0,fracta}), .b({16'b0,fractb}), .o(fractoo));
reg [31:0] p20,p21,p22,p23;
 
reg [31:0] p30,p31,p32,p33;
 
        always @(posedge clk)
        always @(posedge clk)
        if (ce) begin
    if (ce) fract1 <= fractoo[224:0];
                p00 <= fracta[15: 0] * fractb[15: 0];
 
                p01 <= fracta[31:16] * fractb[15: 0];
 
                p02 <= fracta[47:32] * fractb[15: 0];
 
                p03 <= fracta[63:48] * fractb[15: 0];
 
 
 
                p10 <= fracta[15: 0] * fractb[31:16];
 
                p11 <= fracta[31:16] * fractb[31:16];
 
                p12 <= fracta[47:32] * fractb[31:16];
 
                p13 <= fracta[63:48] * fractb[31:16];
 
 
 
                p20 <= fracta[15: 0] * fractb[47:32];
 
                p21 <= fracta[31:16] * fractb[47:32];
 
                p22 <= fracta[47:32] * fractb[47:32];
 
                p23 <= fracta[63:48] * fractb[47:32];
 
 
 
                p30 <= fracta[15: 0] * fractb[63:48];
 
                p31 <= fracta[31:16] * fractb[63:48];
 
                p32 <= fracta[47:32] * fractb[63:48];
 
                p33 <= fracta[63:48] * fractb[63:48];
 
 
 
                fract1 <=                                               {p03,48'b0} + {p02,32'b0} + {p01,16'b0} + p00 +
 
                                                                  {p13,64'b0} + {p12,48'b0} + {p11,32'b0} + {p10,16'b0} +
 
                                        {p23,80'b0} + {p22,64'b0} + {p21,48'b0} + {p20,32'b0} +
 
      {p33,96'b0} + {p32,80'b0} + {p31,64'b0} + {p30,48'b0}
 
                                ;
 
        end
        end
 
else if (FPWID==80) begin
 
  wire [255:0] fractoo;
 
  mult128x128 umul1 (.clk(clk), .ce(ce), .a({63'd0,fracta}), .b({63'd0,fractb}), .o(fractoo));
 
  always @(posedge clk)
 
    if (ce) fract1 <= fractoo[130:0];
end
end
else if (FPWID==64) begin
else if (FPWID==64) begin
reg [35:0] p00,p01,p02;
  wire [127:0] fractoo;
reg [35:0] p10,p11,p12;
  mult64x64 umul1 (.clk(clk), .ce(ce), .a({11'd0,fracta}), .b({11'd0,fractb}), .o(fractoo));
reg [35:0] p20,p21,p22;
 
        always @(posedge clk)
        always @(posedge clk)
        if (ce) begin
    if (ce) fract1 <= fractoo[106:0];
                p00 <= fracta[17: 0] * fractb[17: 0];
 
                p01 <= fracta[35:18] * fractb[17: 0];
 
                p02 <= fracta[52:36] * fractb[17: 0];
 
                p10 <= fracta[17: 0] * fractb[35:18];
 
                p11 <= fracta[35:18] * fractb[35:18];
 
                p12 <= fracta[52:36] * fractb[35:18];
 
                p20 <= fracta[17: 0] * fractb[52:36];
 
                p21 <= fracta[35:18] * fractb[52:36];
 
                p22 <= fracta[52:36] * fractb[52:36];
 
                fract1 <=                                   {p02,36'b0} + {p01,18'b0} + p00 +
 
                                                                  {p12,54'b0} + {p11,36'b0} + {p10,18'b0} +
 
                                        {p22,72'b0} + {p21,54'b0} + {p20,36'b0}
 
                                ;
 
        end
        end
 
else if (FPWID==40) begin
 
  wire [63:0] fractoo;
 
  mult32x32 umul1 (.clk(clk), .ce(ce), .a({3'd0,fracta}), .b({3'd0,fractb}), .o(fractoo));
 
  always @(posedge clk)
 
    if (ce) fract1 <= fractoo[58:0];
end
end
else if (FPWID==32) begin
else if (FPWID==32) begin
reg [23:0] p00,p01,p02;
  reg [23:0] p00,p11;
reg [23:0] p10,p11,p12;
 
reg [23:0] p20,p21,p22;
 
        always @(posedge clk)
        always @(posedge clk)
        if (ce) begin
        if (ce) begin
                p00 <= fracta[11: 0] * fractb[11: 0];
          p00 <= fracta[23: 0] * fractb[11: 0];
                p01 <= fracta[23:12] * fractb[11: 0];
          p11 <= fracta[23: 0] * fractb[23:12];
                p10 <= fracta[11: 0] * fractb[23:12];
                fract1 <= {p11,12'b0} + p00;
                p11 <= fracta[23:12] * fractb[23:12];
 
                fract1 <= {p11,p00} + {p01,12'b0} + {p10,12'b0};
 
        end
        end
end
end
else begin
else begin
        always @(posedge clk)
        always @(posedge clk)
    if (ce) begin
    if (ce) begin
Line 185... Line 175...
// Status
// Status
wire under1, over1;
wire under1, over1;
wire under = ex1[EMSB+2];       // exponent underflow
wire under = ex1[EMSB+2];       // exponent underflow
wire over = (&ex1[EMSB:0] | ex1[EMSB+1]) & !ex1[EMSB+2];
wire over = (&ex1[EMSB:0] | ex1[EMSB+1]) & !ex1[EMSB+2];
 
 
delay2 #(EMSB+1) u3 (.clk(clk), .ce(ce), .i(ex1[EMSB:0]), .o(ex2) );
delay #(.WID(EMSB+1),.DEP(DELAY)) u3 (.clk(clk), .ce(ce), .i(ex1[EMSB:0]), .o(ex2) );
delay2 u2a (.clk(clk), .ce(ce), .i(aInf), .o(aInf1) );
delay #(.WID(1),.DEP(DELAY)) u2a (.clk(clk), .ce(ce), .i(aInf), .o(aInf1) );
delay2 u2b (.clk(clk), .ce(ce), .i(bInf), .o(bInf1) );
delay #(.WID(1),.DEP(DELAY)) u2b (.clk(clk), .ce(ce), .i(bInf), .o(bInf1) );
delay2 u6  (.clk(clk), .ce(ce), .i(under), .o(under1) );
delay #(.WID(1),.DEP(DELAY)) u6  (.clk(clk), .ce(ce), .i(under), .o(under1) );
delay2 u7  (.clk(clk), .ce(ce), .i(over), .o(over1) );
delay #(.WID(1),.DEP(DELAY)) u7  (.clk(clk), .ce(ce), .i(over), .o(over1) );
 
 
// determine when a NaN is output
// determine when a NaN is output
wire qNaNOut;
wire qNaNOut;
wire [FPWID-1:0] a1,b1;
wire [FPWID-1:0] a1,b1;
delay2 u5 (.clk(clk), .ce(ce), .i((aInf&bz)|(bInf&az)), .o(qNaNOut) );
delay #(.WID(1),.DEP(DELAY)) u5 (.clk(clk), .ce(ce), .i((aInf&bz)|(bInf&az)), .o(qNaNOut) );
delay2 u14 (.clk(clk), .ce(ce), .i(aNan), .o(aNan1) );
delay #(.WID(1),.DEP(DELAY)) u14 (.clk(clk), .ce(ce), .i(aNan), .o(aNan1) );
delay2 u15 (.clk(clk), .ce(ce), .i(bNan), .o(bNan1) );
delay #(.WID(1),.DEP(DELAY)) u15 (.clk(clk), .ce(ce), .i(bNan), .o(bNan1) );
delay2 #(FPWID) u16 (.clk(clk), .ce(ce), .i(a), .o(a1) );
delay #(.WID(FPWID),.DEP(DELAY))  u16 (.clk(clk), .ce(ce), .i(a), .o(a1) );
delay2 #(FPWID) u17 (.clk(clk), .ce(ce), .i(b), .o(b1) );
delay #(.WID(FPWID),.DEP(DELAY))  u17 (.clk(clk), .ce(ce), .i(b), .o(b1) );
 
 
// -----------------------------------------------------------
// -----------------------------------------------------------
// Second clock
// Second clock
// - correct xponent and mantissa for exceptional conditions
// - correct xponent and mantissa for exceptional conditions
// -----------------------------------------------------------
// -----------------------------------------------------------
 
 
wire so1;
wire so1;
delay3 u8 (.clk(clk), .ce(ce), .i(sa ^ sb), .o(so1) );// two clock delay!
delay #(.WID(1),.DEP(DELAY+1)) u8 (.clk(clk), .ce(ce), .i(sa ^ sb), .o(so1) );// two clock delay!
 
 
always @(posedge clk)
always @(posedge clk)
        if (ce)
        if (ce)
                casez({qNaNOut|aNan1|bNan1,aInf1,bInf1,over1,under1})
                casez({qNaNOut|aNan1|bNan1,aInf1,bInf1,over1,under1})
                5'b1????:       xo1 = infXp;    // qNaN - infinity * zero
                5'b1????:       xo1 = infXp;    // qNaN - infinity * zero
Line 219... Line 209...
                5'b0001?:       xo1 = infXp;    // result overflow
                5'b0001?:       xo1 = infXp;    // result overflow
                5'b00001:       xo1 = ex2[EMSB:0];//0;          // underflow
                5'b00001:       xo1 = ex2[EMSB:0];//0;          // underflow
                default:        xo1 = ex2[EMSB:0];      // situation normal
                default:        xo1 = ex2[EMSB:0];      // situation normal
                endcase
                endcase
 
 
 
// Force mantissa to zero when underflow or zero exponent when not supporting denormals.
always @(posedge clk)
always @(posedge clk)
        if (ce)
        if (ce)
 
`ifdef SUPPORT_DENORMALS
                casez({aNan1,bNan1,qNaNOut,aInf1,bInf1,over1})
                casez({aNan1,bNan1,qNaNOut,aInf1,bInf1,over1})
 
`else
 
                casez({aNan1,bNan1,qNaNOut,aInf1,bInf1,over1|under1})
 
`endif
                6'b1?????:  mo1 = {1'b1,a1[FMSB:0],{FMSB+1{1'b0}}};
                6'b1?????:  mo1 = {1'b1,a1[FMSB:0],{FMSB+1{1'b0}}};
    6'b01????:  mo1 = {1'b1,b1[FMSB:0],{FMSB+1{1'b0}}};
    6'b01????:  mo1 = {1'b1,b1[FMSB:0],{FMSB+1{1'b0}}};
                6'b001???:      mo1 = {1'b1,qNaN|3'd4,{FMSB+1{1'b0}}};  // multiply inf * zero
                6'b001???:      mo1 = {1'b1,qNaN|3'd4,{FMSB+1{1'b0}}};  // multiply inf * zero
                6'b0001??:      mo1 = 0;        // mul inf's
                6'b0001??:      mo1 = 0;        // mul inf's
                6'b00001?:      mo1 = 0;        // mul inf's
                6'b00001?:      mo1 = 0;        // mul inf's
                6'b000001:      mo1 = 0;        // mul overflow
                6'b000001:      mo1 = 0;        // mul overflow
                default:        mo1 = fract1;
                default:        mo1 = fract1;
                endcase
                endcase
 
 
delay3 u10 (.clk(clk), .ce(ce), .i(sa & sb), .o(sign_exe) );
delay #(.WID(1),.DEP(DELAY+1)) u10 (.clk(clk), .ce(ce), .i(sa & sb), .o(sign_exe) );
delay1 u11 (.clk(clk), .ce(ce), .i(over1),  .o(overflow) );
delay1 u11 (.clk(clk), .ce(ce), .i(over1),  .o(overflow) );
delay1 u12 (.clk(clk), .ce(ce), .i(over1),  .o(inf) );
delay1 u12 (.clk(clk), .ce(ce), .i(over1),  .o(inf) );
delay1 u13 (.clk(clk), .ce(ce), .i(under1), .o(underflow) );
delay1 u13 (.clk(clk), .ce(ce), .i(under1), .o(underflow) );
 
 
assign o = {so1,xo1,mo1};
assign o = {so1,xo1,mo1};
Line 243... Line 238...
endmodule
endmodule
 
 
 
 
// Multiplier with normalization and rounding.
// Multiplier with normalization and rounding.
 
 
module fpMulnr(clk, ce, a, b, o, rm, sign_exe, inf, overflow, underflow);
module fpMultiplynr(clk, ce, a, b, o, rm, sign_exe, inf, overflow, underflow);
input clk;
input clk;
input ce;
input ce;
input  [MSB:0] a, b;
input  [MSB:0] a, b;
output [MSB:0] o;
output [MSB:0] o;
input [2:0] rm;
input [2:0] rm;
Line 258... Line 253...
 
 
wire [EX:0] o1;
wire [EX:0] o1;
wire sign_exe1, inf1, overflow1, underflow1;
wire sign_exe1, inf1, overflow1, underflow1;
wire [MSB+3:0] fpn0;
wire [MSB+3:0] fpn0;
 
 
fpMul       #(FPWID) u1 (clk, ce, a, b, o1, sign_exe1, inf1, overflow1, underflow1);
fpMultiply  u1 (clk, ce, a, b, o1, sign_exe1, inf1, overflow1, underflow1);
fpNormalize #(FPWID) u2(.clk(clk), .ce(ce), .under_i(underflow1), .i(o1), .o(fpn0) );
fpNormalize u2(.clk(clk), .ce(ce), .under_i(underflow1), .i(o1), .o(fpn0) );
fpRound     #(FPWID) u3(.clk(clk), .ce(ce), .rm(rm), .i(fpn0), .o(o) );
fpRound     u3(.clk(clk), .ce(ce), .rm(rm), .i(fpn0), .o(o) );
delay2      #(1)   u4(.clk(clk), .ce(ce), .i(sign_exe1), .o(sign_exe));
delay2      #(1)   u4(.clk(clk), .ce(ce), .i(sign_exe1), .o(sign_exe));
delay2      #(1)   u5(.clk(clk), .ce(ce), .i(inf1), .o(inf));
delay2      #(1)   u5(.clk(clk), .ce(ce), .i(inf1), .o(inf));
delay2      #(1)   u6(.clk(clk), .ce(ce), .i(overflow1), .o(overflow));
delay2      #(1)   u6(.clk(clk), .ce(ce), .i(overflow1), .o(overflow));
delay2      #(1)   u7(.clk(clk), .ce(ce), .i(underflow1), .o(underflow));
delay2      #(1)   u7(.clk(clk), .ce(ce), .i(underflow1), .o(underflow));
endmodule
endmodule

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