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Finished unified divsqrt otfc and fgen name changes

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This commit is contained in:
David Harris 2022-09-19 08:30:59 -07:00
parent 34bd82e4a3
commit a36747fda0
7 changed files with 49 additions and 48 deletions
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2
pipelined/config/shared/wally-shared.vh
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@ -102,7 +102,7 @@
// division constants
`define RADIX 32'h2
`define DIVCOPIES 32'h1
`define DIVCOPIES 32'h5
`define DIVLEN ((`NF < `XLEN) ? (`XLEN) : (`NF + 3))
// `define DIVN (`NF < `XLEN ? `XLEN : `NF+1) // length of input
`define DIVN (`NF < `XLEN ? `XLEN : `NF+3) // length of input

4
pipelined/src/fpu/fdivsqrtiter.sv
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@ -119,13 +119,13 @@ module fdivsqrtiter(
if (`RADIX == 2) begin: stage
fdivsqrtstage2 fdivsqrtstage(.D, .DBar, .D2, .DBar2, .SqrtM,
.WS(WS[i]), .WC(WC[i]), .WSA(WSA[i]), .WCA(WCA[i]),
.C(C[i]), .S(U[i]), .SM(UM[i]), .CNext(C[i+1]), .SNext(UNext[i]), .SMNext(UMNext[i]), .qn(qn[i]));
.C(C[i]), .U(U[i]), .UM(UM[i]), .CNext(C[i+1]), .UNext(UNext[i]), .UMNext(UMNext[i]), .qn(qn[i]));
end else begin: stage
logic j1;
assign j1 = (i == 0 & ~C[0][`DIVb-1]);
fdivsqrtstage4 fdivsqrtstage(.D, .DBar, .D2, .DBar2, .SqrtM, .j1,
.WS(WS[i]), .WC(WC[i]), .WSA(WSA[i]), .WCA(WCA[i]),
.C(C[i]), .S(U[i]), .SM(UM[i]), .CNext(C[i+1]), .SNext(UNext[i]), .SMNext(UMNext[i]), .qn(qn[i]));
.C(C[i]), .U(U[i]), .UM(UM[i]), .CNext(C[i+1]), .UNext(UNext[i]), .UMNext(UMNext[i]), .qn(qn[i]));
end
if(i<(`DIVCOPIES-1)) begin
assign WS[i+1] = WSA[i] << `LOGR;

6
pipelined/src/fpu/fdivsqrtpostproc.sv
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@ -71,11 +71,13 @@ module fdivsqrtpostproc(
// division takes the result from the next cycle, which is shifted to the left one more time so the square root also needs to be shifted
always_comb
if(SqrtM) // sqrt ouputs in the range (1, .5]
if(NegSticky) QmM = FirstUM[`DIVb-(`RADIX/4):0] << SqrtM;
else QmM = FirstU[`DIVb-(`RADIX/4):0] << SqrtM;
/* if(SqrtM) // sqrt ouputs in the range (1, .5]
if(NegSticky) QmM = {FirstUM[`DIVb-1-(`RADIX/4):0], 1'b0};
else QmM = {FirstU[`DIVb-1-(`RADIX/4):0], 1'b0};
else
if(NegSticky) QmM = FirstUM[`DIVb-(`RADIX/4):0];
else QmM = FirstU[`DIVb-(`RADIX/4):0];
else QmM = FirstU[`DIVb-(`RADIX/4):0]; */
endmodule

8
pipelined/src/fpu/fdivsqrtstage2.sv
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@ -34,13 +34,13 @@
module fdivsqrtstage2 (
input logic [`DIVN-2:0] D,
input logic [`DIVb+3:0] DBar, D2, DBar2,
input logic [`DIVb:0] S, SM,
input logic [`DIVb:0] U, UM,
input logic [`DIVb+3:0] WS, WC,
input logic [`DIVb+1:0] C,
input logic SqrtM,
output logic qn,
output logic [`DIVb+1:0] CNext,
output logic [`DIVb:0] SNext, SMNext,
output logic [`DIVb:0] UNext, UMNext,
output logic [`DIVb+3:0] WSA, WCA
);
/* verilator lint_on UNOPTFLAT */
@ -61,7 +61,7 @@ module fdivsqrtstage2 (
// 0010 = -1
// 0001 = -2
qsel2 qsel2(WS[`DIVb+3:`DIVb], WC[`DIVb+3:`DIVb], qp, qz, qn);
fgen2 fgen2(.sp(qp), .sz(qz), .C(CNext), .S, .SM, .F);
fgen2 fgen2(.sp(qp), .sz(qz), .C(CNext), .U, .UM, .F);
assign Dsel = {`DIVb+4{~qz}}&(qp ? DBar : {3'b0, 1'b1, D, {`DIVb-`DIVN+1{1'b0}}});
// Partial Product Generation
@ -69,7 +69,7 @@ module fdivsqrtstage2 (
assign AddIn = SqrtM ? F : Dsel;
csa #(`DIVb+4) csa(WS, WC, AddIn, qp&~SqrtM, WSA, WCA);
sotfc2 sotfc2(.sp(qp), .sz(qz), .C(CNext), .S, .SM, .SNext, .SMNext);
uotfc2 uotfc2(.sp(qp), .sz(qz), .C(CNext), .U, .UM, .UNext, .UMNext);
endmodule

10
pipelined/src/fpu/fdivsqrtstage4.sv
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@ -34,13 +34,13 @@
module fdivsqrtstage4 (
input logic [`DIVN-2:0] D,
input logic [`DIVb+3:0] DBar, D2, DBar2,
input logic [`DIVb:0] S, SM,
input logic [`DIVb:0] U, UM,
input logic [`DIVb+3:0] WS, WC,
input logic [`DIVb+1:0] C,
output logic [`DIVb+1:0] CNext,
input logic SqrtM, j1,
output logic qn,
output logic [`DIVb:0] SNext, SMNext,
output logic [`DIVb:0] UNext, UMNext,
output logic [`DIVb+3:0] WSA, WCA
);
/* verilator lint_on UNOPTFLAT */
@ -61,9 +61,9 @@ module fdivsqrtstage4 (
// 0000 = 0
// 0010 = -1
// 0001 = -2
assign Smsbs = S[`DIVb:`DIVb-4];
assign Smsbs = U[`DIVb:`DIVb-4];
qsel4 qsel4(.D, .Smsbs, .WS, .WC, .Sqrt(SqrtM), .j1, .q);
fgen4 fgen4(.s(q), .C({2'b11, CNext}), .S({3'b000, S}), .SM({3'b000, SM}), .F);
fgen4 fgen4(.s(q), .C({2'b11, CNext}), .U({3'b000, U}), .UM({3'b000, UM}), .F);
always_comb
case (q)
@ -81,7 +81,7 @@ module fdivsqrtstage4 (
assign CarryIn = ~SqrtM & (q[3] | q[2]); // +1 for 2's complement of -D and -2D
csa #(`DIVb+4) csa(WS, WC, AddIn, CarryIn, WSA, WCA);
sotfc4 sotfc4(.s(q), .Sqrt(SqrtM), .C(CNext[`DIVb:0]), .S, .SM, .SNext, .SMNext);
uotfc4 uotfc4(.s(q), .Sqrt(SqrtM), .C(CNext[`DIVb:0]), .U, .UM, .UNext, .UMNext);
assign qn = 0; // unused for radix 4
endmodule

51
pipelined/src/fpu/otfc.sv
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@ -31,45 +31,44 @@
`include "wally-config.vh"
///////////////////////////////
// Square Root OTFC, Radix 2 //
// Un ified OTFC, Radix 2 //
///////////////////////////////
module sotfc2(
module uotfc2(
input logic sp, sz,
input logic [`DIVb+1:0] C,
input logic [`DIVb:0] S, SM,
output logic [`DIVb:0] SNext, SMNext
input logic [`DIVb:0] U, UM,
output logic [`DIVb:0] UNext, UMNext
);
// The on-the-fly converter transfers the square root
// The on-the-fly converter transfers the divsqrt
// bits to the quotient as they come.
// Use this otfc for division and square root.
logic [`DIVb:0] K;
assign K = (C[`DIVb:0] & ~(C[`DIVb:0] << 1));
always_comb begin
if (sp) begin
SNext = S | K;
SMNext = S;
UNext = U | K;
UMNext = U;
end else if (sz) begin
SNext = S;
SMNext = SM | K;
UNext = U;
UMNext = UM | K;
end else begin // If sp and sz are not true, then sn is
SNext = SM | K;
SMNext = SM;
UNext = UM | K;
UMNext = UM;
end
end
endmodule
///////////////////////////////
// Square Root OTFC, Radix 4 //
// Unified OTFC, Radix 4 //
///////////////////////////////
module sotfc4(
module uotfc4(
input logic [3:0] s,
input logic Sqrt,
input logic [`DIVb:0] S, SM,
input logic [`DIVb:0] U, UM,
input logic [`DIVb:0] C,
output logic [`DIVb:0] SNext, SMNext
output logic [`DIVb:0] UNext, UMNext
);
// The on-the-fly converter transfers the square root
// bits to the quotient as they come.
@ -82,20 +81,20 @@ module sotfc4(
always_comb begin
if (s[3]) begin
SNext = S | K2;
SMNext = S | K1;
UNext = U | K2;
UMNext = U | K1;
end else if (s[2]) begin
SNext = S | K1;
SMNext = S;
UNext = U | K1;
UMNext = U;
end else if (s[1]) begin
SNext = SM | K3;
SMNext = SM | K2;
UNext = UM | K3;
UMNext = UM | K2;
end else if (s[0]) begin
SNext = SM | K2;
SMNext = SM | K1;
UNext = UM | K2;
UMNext = UM | K1;
end else begin // If sp and sn are not true, then sz is
SNext = S;
SMNext = SM | K3;
UNext = U;
UMNext = UM | K3;
end
end

16
pipelined/src/fpu/qsel.sv
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@ -68,14 +68,14 @@ endmodule
module fgen2 (
input logic sp, sz,
input logic [`DIVb+1:0] C,
input logic [`DIVb:0] S, SM,
input logic [`DIVb:0] U, UM,
output logic [`DIVb+3:0] F
);
logic [`DIVb+3:0] FP, FN, FZ;
logic [`DIVb+3:0] SExt, SMExt, CExt;
assign SExt = {3'b0, S};
assign SMExt = {3'b0, SM};
assign SExt = {3'b0, U};
assign SMExt = {3'b0, UM};
assign CExt = {2'b11, C}; // extend C from Q2.k to Q4.k
// Generate for both positive and negative bits
@ -254,17 +254,17 @@ endmodule
////////////////////////////////////
module fgen4 (
input logic [3:0] s,
input logic [`DIVb+3:0] C, S, SM,
input logic [`DIVb+3:0] C, U, UM,
output logic [`DIVb+3:0] F
);
logic [`DIVb+3:0] F2, F1, F0, FN1, FN2;
// Generate for both positive and negative bits
assign F2 = (~S << 2) & (C << 2);
assign F1 = ~(S << 1) & C;
assign F2 = (~U << 2) & (C << 2);
assign F1 = ~(U << 1) & C;
assign F0 = '0;
assign FN1 = (SM << 1) | (C & ~(C << 3));
assign FN2 = (SM << 2) | ((C << 2)&~(C << 4));
assign FN1 = (UM << 1) | (C & ~(C << 3));
assign FN2 = (UM << 2) | ((C << 2)&~(C << 4));
// Choose which adder input will be used