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Partitioned fma into separate files

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This commit is contained in:
David Harris 2022-08-01 18:07:38 +00:00
parent d2de84a456
commit e3b970d3ff
9 changed files with 384 additions and 225 deletions
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2
pipelined/regression/sim-wally-batch
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@ -1 +1 @@
vsim -c -do "do wally-pipelined-batch.do rv32gc wally32periph" vsim -c -do "do wally-pipelined-batch.do rv64gc arch64d"

231
pipelined/src/fpu/fma.sv
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@ -1,7 +1,7 @@
/////////////////////////////////////////// ///////////////////////////////////////////
// //
// Written: me@KatherineParry.com, David Harris // Written: 6/23/2021 me@KatherineParry.com, David_Harris@hmc.edu
// Modified: 6/23/2021 // Modified:
// //
// Purpose: Floating point multiply-accumulate of configurable size // Purpose: Floating point multiply-accumulate of configurable size
// //
@ -63,18 +63,18 @@ module fma(
// calculate the product's exponent // calculate the product's exponent
expadd expadd(.Fmt, .Xe, .Ye, .XZero, .YZero, .Pe); fmaexpadd expadd(.Fmt, .Xe, .Ye, .XZero, .YZero, .Pe);
// multiplication of the mantissa's // multiplication of the mantissa's
mult mult(.Xm, .Ym, .Pm); fmamult mult(.Xm, .Ym, .Pm);
/////////////////////////////////////////////////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////
// Alignment shifter // Alignment shifter
/////////////////////////////////////////////////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////
// calculate the signs and take the opperation into account // calculate the signs and take the opperation into account
sign sign(.OpCtrl, .Xs, .Ys, .Zs, .Ps, .As); fmasign sign(.OpCtrl, .Xs, .Ys, .Zs, .Ps, .As);
align align(.Ze, .Zm, .XZero, .YZero, .ZZero, .Xe, .Ye, fmaalign align(.Ze, .Zm, .XZero, .YZero, .ZZero, .Xe, .Ye,
.Am, .ZmSticky, .KillProd); .Am, .ZmSticky, .KillProd);
@ -83,223 +83,8 @@ module fma(
// // Addition/LZA // // Addition/LZA
// /////////////////////////////////////////////////////////////////////////////// // ///////////////////////////////////////////////////////////////////////////////
add add(.Am, .Pm, .Ze, .Pe, .Ps, .As, .KillProd, .ZmSticky, .AmInv, .PmKilled, .NegSum, .InvA, .Sm, .Se, .Ss); fmaadd add(.Am, .Pm, .Ze, .Pe, .Ps, .As, .KillProd, .ZmSticky, .AmInv, .PmKilled, .NegSum, .InvA, .Sm, .Se, .Ss);
loa loa(.A(AmInv+{(3*`NF+6)'(0),InvA&~((ZmSticky&~KillProd))}), .P({PmKilled, 1'b0, InvA&Ps&ZmSticky&KillProd}), .SCnt); fmalza lza(.A(AmInv+{(3*`NF+6)'(0),InvA&~((ZmSticky&~KillProd))}), .P({PmKilled, 1'b0, InvA&Ps&ZmSticky&KillProd}), .SCnt);
endmodule endmodule
module expadd(
input logic [`FMTBITS-1:0] Fmt, // format of the output: single double half quad
input logic [`NE-1:0] Xe, Ye, // input's exponents
input logic XZero, YZero, // are the inputs zero
output logic [`NE+1:0] Pe // product's exponent B^(1023)NE+2
);
// kill the exponent if the product is zero - either X or Y is 0
assign Pe = ({2'b0, Xe} + {2'b0, Ye} - {2'b0, (`NE)'(`BIAS)})&{`NE+2{~(XZero|YZero)}};
endmodule
module mult(
input logic [`NF:0] Xm, Ym,
output logic [2*`NF+1:0] Pm
);
assign Pm = Xm * Ym;
endmodule
module sign(
input logic [2:0] OpCtrl, // opperation contol
input logic Xs, Ys, Zs, // sign of the inputs
output logic Ps, // the product's sign - takes opperation into account
output logic As // aligned addend sign used in fma - takes opperation into account
);
// Calculate the product's sign
// Negate product's sign if FNMADD or FNMSUB
// flip is negation opperation
assign Ps = Xs ^ Ys ^ (OpCtrl[1]&~OpCtrl[2]);
// flip if subtraction
assign As = Zs^OpCtrl[0];
endmodule
module align(
input logic [`NE-1:0] Xe, Ye, Ze, // biased exponents in B(NE.0) format
input logic [`NF:0] Zm, // significand in U(0.NF) format]
input logic XZero, YZero, ZZero, // is the input zero
output logic [3*`NF+5:0] Am, // addend aligned for addition in U(NF+5.2NF+1)
output logic ZmSticky, // Sticky bit calculated from the aliged addend
output logic KillProd // should the product be set to zero
);
logic [`NE+1:0] ACnt; // how far to shift the addend to align with the product in Q(NE+2.0) format
logic [4*`NF+5:0] ZmShifted; // output of the alignment shifter including sticky bits U(NF+5.3NF+1)
logic [4*`NF+5:0] ZmPreshifted; // input to the alignment shifter U(NF+5.3NF+1)
logic KillZ;
///////////////////////////////////////////////////////////////////////////////
// Alignment shifter
///////////////////////////////////////////////////////////////////////////////
// determine the shift count for alignment
// - negitive means Z is larger, so shift Z left
// - positive means the product is larger, so shift Z right
// This could have been done using Pe, but ACnt is on the critical path so we replicate logic for speed
assign ACnt = {2'b0, Xe} + {2'b0, Ye} - {2'b0, (`NE)'(`BIAS)} + (`NE+2)'(`NF+3) - {2'b0, Ze};
// Defualt Addition without shifting
// | 54'b0 | 106'b(product) | 2'b0 |
// | addnend |
// the 1'b0 before the added is because the product's mantissa has two bits before the binary point (xx.xxxxxxxxxx...)
assign ZmPreshifted = {Zm,(3*`NF+5)'(0)};
assign KillProd = (ACnt[`NE+1]&~ZZero)|XZero|YZero;
assign KillZ = $signed(ACnt)>$signed((`NE+2)'(3)*(`NE+2)'(`NF)+(`NE+2)'(5));
always_comb
begin
// If the product is too small to effect the sum, kill the product
// | 54'b0 | 106'b(product) | 2'b0 |
// | addnend |
if (KillProd) begin
ZmShifted = {(`NF+3)'(0), Zm, (2*`NF+2)'(0)};
ZmSticky = ~(XZero|YZero);
// If the addend is too small to effect the addition
// - The addend has to shift two past the end of the addend to be considered too small
// - The 2 extra bits are needed for rounding
// | 54'b0 | 106'b(product) | 2'b0 |
// | addnend |
end else if (KillZ) begin
ZmShifted = 0;
ZmSticky = ~ZZero;
// If the Addend is shifted right
// | 54'b0 | 106'b(product) | 2'b0 |
// | addnend |
end else begin
ZmShifted = ZmPreshifted >> ACnt;
ZmSticky = |(ZmShifted[`NF-1:0]);
end
end
assign Am = ZmShifted[4*`NF+5:`NF];
endmodule
module add(
input logic [3*`NF+5:0] Am, // aligned addend's mantissa for addition in U(NF+5.2NF+1)
input logic [2*`NF+1:0] Pm, // the product's mantissa
input logic Ps, As,// the product sign and the alligend addeded's sign (Modified Z sign for other opperations)
input logic KillProd, // should the product be set to 0
input logic ZmSticky,
input logic [`NE-1:0] Ze,
input logic [`NE+1:0] Pe,
output logic [3*`NF+6:0] AmInv, // aligned addend possibly inverted
output logic [2*`NF+1:0] PmKilled, // the product's mantissa possibly killed
output logic NegSum, // was the sum negitive
output logic InvA, // do you invert the aligned addend
output logic Ss,
output logic [`NE+1:0] Se,
output logic [3*`NF+5:0] Sm // the positive sum
);
logic [3*`NF+6:0] PreSum, NegPreSum; // possibly negitive sum
///////////////////////////////////////////////////////////////////////////////
// Addition
///////////////////////////////////////////////////////////////////////////////
// Negate Z when doing one of the following opperations:
// -prod + Z
// prod - Z
assign InvA = As ^ Ps;
// Choose an inverted or non-inverted addend - the one has to be added now for the LZA
assign AmInv = InvA ? {1'b1, ~Am} : {1'b0, Am};
// Kill the product if the product is too small to effect the addition (determined in fma1.sv)
assign PmKilled = Pm&{2*`NF+2{~KillProd}};
// Do the addition
// - calculate a positive and negitive sum in parallel
// Zsticky Psticky
// PreSum -1 = don't add 1 +1 = add 2
// NegPreSum +1 = add 2 -1 = don't add 1
// for NegPreSum the product is set to -1 whenever the product is killed, therefore add 1, 2 or 0
assign PreSum = {{`NF+3{1'b0}}, PmKilled, 1'b0, InvA&ZmSticky&KillProd} + AmInv + {{3*`NF+6{1'b0}}, InvA&~((ZmSticky&~KillProd))};
assign NegPreSum = {1'b0, Am} + {{`NF+3{1'b1}}, ~PmKilled, 2'b11} + {(3*`NF+5)'(0), ZmSticky&~KillProd, ~(ZmSticky)};
// Is the sum negitive
assign NegSum = PreSum[3*`NF+6];
// Choose the positive sum and accompanying LZA result.
assign Sm = NegSum ? NegPreSum[3*`NF+5:0] : PreSum[3*`NF+5:0];
// is the result negitive
// if p - z is the Sum negitive
// if -p + z is the Sum positive
// if -p - z then the Sum is negitive
assign Ss = NegSum^Ps; //*** move to execute stage
assign Se = KillProd ? {2'b0, Ze} : Pe;
endmodule
module loa( // [Schmookler & Nowka, Leading zero anticipation and detection, IEEE Sym. Computer Arithmetic, 2001]
input logic [3*`NF+6:0] A, // addend
input logic [2*`NF+3:0] P, // product
output logic [$clog2(3*`NF+7)-1:0] SCnt // normalization shift count for the positive result
);
logic [3*`NF+6:0] T;
logic [3*`NF+6:0] G;
logic [3*`NF+6:0] Z;
logic [3*`NF+6:0] f;
assign T[3*`NF+6:2*`NF+4] = A[3*`NF+6:2*`NF+4];
assign G[3*`NF+6:2*`NF+4] = 0;
assign Z[3*`NF+6:2*`NF+4] = ~A[3*`NF+6:2*`NF+4];
assign T[2*`NF+3:0] = A[2*`NF+3:0]^P;
assign G[2*`NF+3:0] = A[2*`NF+3:0]&P;
assign Z[2*`NF+3:0] = ~A[2*`NF+3:0]&~P;
// Apply function to determine Leading pattern
// - note: the paper linked above uses the numbering system where 0 is the most significant bit
//f[n] = ~T[n]&T[n-1] note: n is the MSB
//f[i] = (T[i+1]&(G[i]&~Z[i-1] | Z[i]&~G[i-1])) | (~T[i+1]&(Z[i]&~Z[i-1] | G[i]&~G[i-1]))
assign f[3*`NF+6] = ~T[3*`NF+6]&T[3*`NF+5];
assign f[3*`NF+5:0] = (T[3*`NF+6:1]&(G[3*`NF+5:0]&{~Z[3*`NF+4:0], 1'b0} | Z[3*`NF+5:0]&{~G[3*`NF+4:0], 1'b1})) | (~T[3*`NF+6:1]&(Z[3*`NF+5:0]&{~Z[3*`NF+4:0], 1'b0} | G[3*`NF+5:0]&{~G[3*`NF+4:0], 1'b1}));
lzc #(3*`NF+7) lzc (.num(f), .ZeroCnt(SCnt));
endmodule

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pipelined/src/fpu/fmaadd.sv Normal file
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///////////////////////////////////////////
//
// Written: 6/23/2021 me@KatherineParry.com, David_Harris@hmc.edu
// Modified:
//
// Purpose: FMA significand adder
//
// A component of the Wally configurable RISC-V project.
//
// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University
//
// MIT LICENSE
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
// BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
// OR OTHER DEALINGS IN THE SOFTWARE.
////////////////////////////////////////////////////////////////////////////////////////////////
`include "wally-config.vh"
module fmaadd(
input logic [3*`NF+5:0] Am, // aligned addend's mantissa for addition in U(NF+5.2NF+1)
input logic [2*`NF+1:0] Pm, // the product's mantissa
input logic Ps, As,// the product sign and the alligend addeded's sign (Modified Z sign for other opperations)
input logic KillProd, // should the product be set to 0
input logic ZmSticky,
input logic [`NE-1:0] Ze,
input logic [`NE+1:0] Pe,
output logic [3*`NF+6:0] AmInv, // aligned addend possibly inverted
output logic [2*`NF+1:0] PmKilled, // the product's mantissa possibly killed
output logic NegSum, // was the sum negitive
output logic InvA, // do you invert the aligned addend
output logic Ss,
output logic [`NE+1:0] Se,
output logic [3*`NF+5:0] Sm // the positive sum
);
logic [3*`NF+6:0] PreSum, NegPreSum; // possibly negitive sum
///////////////////////////////////////////////////////////////////////////////
// Addition
///////////////////////////////////////////////////////////////////////////////
// Negate Z when doing one of the following opperations:
// -prod + Z
// prod - Z
assign InvA = As ^ Ps;
// Choose an inverted or non-inverted addend - the one has to be added now for the LZA
assign AmInv = InvA ? {1'b1, ~Am} : {1'b0, Am};
// Kill the product if the product is too small to effect the addition (determined in fma1.sv)
assign PmKilled = Pm&{2*`NF+2{~KillProd}};
// Do the addition
// - calculate a positive and negitive sum in parallel
// Zsticky Psticky
// PreSum -1 = don't add 1 +1 = add 2
// NegPreSum +1 = add 2 -1 = don't add 1
// for NegPreSum the product is set to -1 whenever the product is killed, therefore add 1, 2 or 0
assign PreSum = {{`NF+3{1'b0}}, PmKilled, 1'b0, InvA&ZmSticky&KillProd} + AmInv + {{3*`NF+6{1'b0}}, InvA&~((ZmSticky&~KillProd))};
assign NegPreSum = {1'b0, Am} + {{`NF+3{1'b1}}, ~PmKilled, 2'b11} + {(3*`NF+5)'(0), ZmSticky&~KillProd, ~(ZmSticky)};
// Is the sum negitive
assign NegSum = PreSum[3*`NF+6];
// Choose the positive sum and accompanying LZA result.
assign Sm = NegSum ? NegPreSum[3*`NF+5:0] : PreSum[3*`NF+5:0];
// is the result negitive
// if p - z is the Sum negitive
// if -p + z is the Sum positive
// if -p - z then the Sum is negitive
assign Ss = NegSum^Ps; //*** move to execute stage
assign Se = KillProd ? {2'b0, Ze} : Pe;
endmodule

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///////////////////////////////////////////
//
// Written: 6/23/2021 me@KatherineParry.com, David_Harris@hmc.edu
// Modified:
//
// Purpose: FMA alginment shift
//
// A component of the Wally configurable RISC-V project.
//
// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University
//
// MIT LICENSE
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
// BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
// OR OTHER DEALINGS IN THE SOFTWARE.
////////////////////////////////////////////////////////////////////////////////////////////////
`include "wally-config.vh"
module fmaalign(
input logic [`NE-1:0] Xe, Ye, Ze, // biased exponents in B(NE.0) format
input logic [`NF:0] Zm, // significand in U(0.NF) format]
input logic XZero, YZero, ZZero, // is the input zero
output logic [3*`NF+5:0] Am, // addend aligned for addition in U(NF+5.2NF+1)
output logic ZmSticky, // Sticky bit calculated from the aliged addend
output logic KillProd // should the product be set to zero
);
logic [`NE+1:0] ACnt; // how far to shift the addend to align with the product in Q(NE+2.0) format
logic [4*`NF+5:0] ZmShifted; // output of the alignment shifter including sticky bits U(NF+5.3NF+1)
logic [4*`NF+5:0] ZmPreshifted; // input to the alignment shifter U(NF+5.3NF+1)
logic KillZ;
///////////////////////////////////////////////////////////////////////////////
// Alignment shifter
///////////////////////////////////////////////////////////////////////////////
// determine the shift count for alignment
// - negitive means Z is larger, so shift Z left
// - positive means the product is larger, so shift Z right
// This could have been done using Pe, but ACnt is on the critical path so we replicate logic for speed
assign ACnt = {2'b0, Xe} + {2'b0, Ye} - {2'b0, (`NE)'(`BIAS)} + (`NE+2)'(`NF+3) - {2'b0, Ze};
// Defualt Addition without shifting
// | 54'b0 | 106'b(product) | 2'b0 |
// | addnend |
// the 1'b0 before the added is because the product's mantissa has two bits before the binary point (xx.xxxxxxxxxx...)
assign ZmPreshifted = {Zm,(3*`NF+5)'(0)};
assign KillProd = (ACnt[`NE+1]&~ZZero)|XZero|YZero;
assign KillZ = $signed(ACnt)>$signed((`NE+2)'(3)*(`NE+2)'(`NF)+(`NE+2)'(5));
always_comb
begin
// If the product is too small to effect the sum, kill the product
// | 54'b0 | 106'b(product) | 2'b0 |
// | addnend |
if (KillProd) begin
ZmShifted = {(`NF+3)'(0), Zm, (2*`NF+2)'(0)};
ZmSticky = ~(XZero|YZero);
// If the addend is too small to effect the addition
// - The addend has to shift two past the end of the addend to be considered too small
// - The 2 extra bits are needed for rounding
// | 54'b0 | 106'b(product) | 2'b0 |
// | addnend |
end else if (KillZ) begin
ZmShifted = 0;
ZmSticky = ~ZZero;
// If the Addend is shifted right
// | 54'b0 | 106'b(product) | 2'b0 |
// | addnend |
end else begin
ZmShifted = ZmPreshifted >> ACnt;
ZmSticky = |(ZmShifted[`NF-1:0]);
end
end
assign Am = ZmShifted[4*`NF+5:`NF];
endmodule

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///////////////////////////////////////////
//
// Written: 6/23/2021 me@KatherineParry.com, David_Harris@hmc.edu
// Modified:
//
// Purpose: FMA exponent addition
//
// A component of the Wally configurable RISC-V project.
//
// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University
//
// MIT LICENSE
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
// BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
// OR OTHER DEALINGS IN THE SOFTWARE.
////////////////////////////////////////////////////////////////////////////////////////////////
`include "wally-config.vh"
module fmaexpadd(
input logic [`FMTBITS-1:0] Fmt, // format of the output: single double half quad
input logic [`NE-1:0] Xe, Ye, // input's exponents
input logic XZero, YZero, // are the inputs zero
output logic [`NE+1:0] Pe // product's exponent B^(1023)NE+2
);
// kill the exponent if the product is zero - either X or Y is 0
assign Pe = ({2'b0, Xe} + {2'b0, Ye} - {2'b0, (`NE)'(`BIAS)})&{`NE+2{~(XZero|YZero)}};
endmodule

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///////////////////////////////////////////
//
// Written: 6/23/2021 me@KatherineParry.com, David_Harris@hmc.edu
// Modified:
//
// Purpose: Leading Zero Anticipator
//
// A component of the Wally configurable RISC-V project.
//
// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University
//
// MIT LICENSE
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
// BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
// OR OTHER DEALINGS IN THE SOFTWARE.
////////////////////////////////////////////////////////////////////////////////////////////////
`include "wally-config.vh"
module fmalza( // [Schmookler & Nowka, Leading zero anticipation and detection, IEEE Sym. Computer Arithmetic, 2001]
input logic [3*`NF+6:0] A, // addend
input logic [2*`NF+3:0] P, // product
output logic [$clog2(3*`NF+7)-1:0] SCnt // normalization shift count for the positive result
);
logic [3*`NF+6:0] T;
logic [3*`NF+6:0] G;
logic [3*`NF+6:0] Z;
logic [3*`NF+6:0] f;
assign T[3*`NF+6:2*`NF+4] = A[3*`NF+6:2*`NF+4];
assign G[3*`NF+6:2*`NF+4] = 0;
assign Z[3*`NF+6:2*`NF+4] = ~A[3*`NF+6:2*`NF+4];
assign T[2*`NF+3:0] = A[2*`NF+3:0]^P;
assign G[2*`NF+3:0] = A[2*`NF+3:0]&P;
assign Z[2*`NF+3:0] = ~A[2*`NF+3:0]&~P;
// Apply function to determine Leading pattern
// - note: the paper linked above uses the numbering system where 0 is the most significant bit
//f[n] = ~T[n]&T[n-1] note: n is the MSB
//f[i] = (T[i+1]&(G[i]&~Z[i-1] | Z[i]&~G[i-1])) | (~T[i+1]&(Z[i]&~Z[i-1] | G[i]&~G[i-1]))
assign f[3*`NF+6] = ~T[3*`NF+6]&T[3*`NF+5];
assign f[3*`NF+5:0] = (T[3*`NF+6:1]&(G[3*`NF+5:0]&{~Z[3*`NF+4:0], 1'b0} | Z[3*`NF+5:0]&{~G[3*`NF+4:0], 1'b1})) | (~T[3*`NF+6:1]&(Z[3*`NF+5:0]&{~Z[3*`NF+4:0], 1'b0} | G[3*`NF+5:0]&{~G[3*`NF+4:0], 1'b1}));
lzc #(3*`NF+7) lzc (.num(f), .ZeroCnt(SCnt));
endmodule

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///////////////////////////////////////////
//
// Written: 6/23/2021 me@KatherineParry.com, David_Harris@hmc.edu
// Modified:
//
// Purpose: FMA Significand Multiplier
//
// A component of the Wally configurable RISC-V project.
//
// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University
//
// MIT LICENSE
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
// BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
// OR OTHER DEALINGS IN THE SOFTWARE.
////////////////////////////////////////////////////////////////////////////////////////////////
`include "wally-config.vh"
module fmamult(
input logic [`NF:0] Xm, Ym,
output logic [2*`NF+1:0] Pm
);
assign Pm = Xm * Ym;
endmodule

47
pipelined/src/fpu/fmasign.sv Normal file
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@ -0,0 +1,47 @@
///////////////////////////////////////////
//
// Written: 6/23/2021 me@KatherineParry.com, David_Harris@hmc.edu
// Modified:
//
// Purpose: FMA Sign Logic
//
// A component of the Wally configurable RISC-V project.
//
// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University
//
// MIT LICENSE
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
// BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
// OR OTHER DEALINGS IN THE SOFTWARE.
////////////////////////////////////////////////////////////////////////////////////////////////
`include "wally-config.vh"
module fmasign(
input logic [2:0] OpCtrl, // opperation contol
input logic Xs, Ys, Zs, // sign of the inputs
output logic Ps, // the product's sign - takes opperation into account
output logic As // aligned addend sign used in fma - takes opperation into account
);
// Calculate the product's sign
// Negate product's sign if FNMADD or FNMSUB
// flip is negation opperation
assign Ps = Xs ^ Ys ^ (OpCtrl[1]&~OpCtrl[2]);
// flip if subtraction
assign As = Zs^OpCtrl[0];
endmodule

3
pipelined/testbench/tests.vh
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@ -1902,7 +1902,8 @@ string imperas32f[] = '{
"rv32i_m/privilege/src/WALLY-gpio-01.S", "rv32i_m/privilege/src/WALLY-gpio-01.S",
"rv32i_m/privilege/src/WALLY-clint-01.S", "rv32i_m/privilege/src/WALLY-clint-01.S",
"rv32i_m/privilege/src/WALLY-uart-01.S", "rv32i_m/privilege/src/WALLY-uart-01.S",
"rv32i_m/privilege/src/WALLY-plic-01.S" "rv32i_m/privilege/src/WALLY-plic-01.S",
"rv32i_m/privilege/src/WALLY-plic-s-01.S"
}; };