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Merge branch 'main' of github.com:davidharrishmc/riscv-wally into main

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slmnemo 2022-06-03 18:56:29 -07:00
commit 7f70655113
3 changed files with 122 additions and 115 deletions
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2
pipelined/srt/srt.do
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@ -17,7 +17,7 @@ if [file exists work] {
} }
vlib work vlib work
vlog +incdir+../config/rv64gc +incdir+../config/shared srt.sv testbench.sv ../src/generic/flop/flop*.sv ../src/generic/mux.sv vlog +incdir+../config/rv64gc +incdir+../config/shared srt.sv testbench.sv ../src/generic/flop/flop*.sv ../src/generic/mux.sv ../src/generic/lzc.sv
vopt +acc work.testbench -o workopt vopt +acc work.testbench -o workopt
vsim workopt vsim workopt

208
pipelined/srt/srt.sv
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@ -30,7 +30,11 @@
`include "wally-config.vh" `include "wally-config.vh"
module srt #(parameter Nf=52) ( `define DIVLEN ((`NF<(`XLEN+1)) ? (`XLEN + 1) : `NF)
`define EXTRAFRACBITS ((`NF<(`XLEN+1)) ? (`XLEN - `NF + 1) : 0)
`define EXTRAINTBITS ((`NF<(`XLEN+1)) ? 0 : (`NF - `XLEN))
module srt (
input logic clk, input logic clk,
input logic Start, input logic Start,
input logic Stall, // *** multiple pipe stages input logic Stall, // *** multiple pipe stages
@ -39,7 +43,7 @@ module srt #(parameter Nf=52) (
// later add exponents, signs, special cases // later add exponents, signs, special cases
input logic XSign, YSign, input logic XSign, YSign,
input logic [`NE-1:0] XExp, YExp, input logic [`NE-1:0] XExp, YExp,
input logic [Nf-1:0] SrcXFrac, SrcYFrac, input logic [`NF-1:0] SrcXFrac, SrcYFrac,
input logic [`XLEN-1:0] SrcA, SrcB, input logic [`XLEN-1:0] SrcA, SrcB,
input logic [1:0] Fmt, // Floats: 00 = 16 bit, 01 = 32 bit, 10 = 64 bit, 11 = 128 bit input logic [1:0] Fmt, // Floats: 00 = 16 bit, 01 = 32 bit, 10 = 64 bit, 11 = 128 bit
input logic W64, // 32-bit ints on XLEN=64 input logic W64, // 32-bit ints on XLEN=64
@ -47,7 +51,7 @@ module srt #(parameter Nf=52) (
input logic Int, // Choose integer inputs input logic Int, // Choose integer inputs
input logic Sqrt, // perform square root, not divide input logic Sqrt, // perform square root, not divide
output logic rsign, output logic rsign,
output logic [Nf-1:0] Quot, Rem, QuotOTFC, // *** later handle integers output logic [`DIVLEN-1:0] Quot, Rem, QuotOTFC, // *** later handle integers
output logic [`NE-1:0] rExp, output logic [`NE-1:0] rExp,
output logic [3:0] Flags output logic [3:0] Flags
); );
@ -55,38 +59,40 @@ module srt #(parameter Nf=52) (
logic qp, qz, qm; // quotient is +1, 0, or -1 logic qp, qz, qm; // quotient is +1, 0, or -1
logic [`NE-1:0] calcExp; logic [`NE-1:0] calcExp;
logic calcSign; logic calcSign;
logic [Nf-1:0] X, Dpreproc; logic [`DIVLEN-1:0] X, Dpreproc;
logic [Nf+3:0] WS, WSA, WSN, WC, WCA, WCN, D, Db, Dsel; logic [`DIVLEN+3:0] WS, WSA, WSN, WC, WCA, WCN, D, Db, Dsel;
logic [Nf+2:0] rp, rm; logic [`DIVLEN+2:0] rp, rm;
logic [$clog2(`XLEN+1)-1:0] intExp;
logic intSign;
srtpreproc #(Nf) preproc(SrcA, SrcB, SrcXFrac, SrcYFrac, Fmt, W64, Signed, Int, Sqrt, X, Dpreproc); srtpreproc preproc(SrcA, SrcB, SrcXFrac, SrcYFrac, Fmt, W64, Signed, Int, Sqrt, X, Dpreproc, intExp, intSign);
// Top Muxes and Registers // Top Muxes and Registers
// When start is asserted, the inputs are loaded into the divider. // When start is asserted, the inputs are loaded into the divider.
// Otherwise, the divisor is retained and the partial remainder // Otherwise, the divisor is retained and the partial remainder
// is fed back for the next iteration. // is fed back for the next iteration.
mux2 #(Nf+4) wsmux({WSA[54:0], 1'b0}, {4'b0001, X}, Start, WSN); mux2 #(`DIVLEN+4) wsmux({WSA[`DIVLEN+2:0], 1'b0}, {4'b0001, X}, Start, WSN);
flop #(Nf+4) wsflop(clk, WSN, WS); flop #(`DIVLEN+4) wsflop(clk, WSN, WS);
mux2 #(Nf+4) wcmux({WCA[54:0], 1'b0}, 56'b0, Start, WCN); mux2 #(`DIVLEN+4) wcmux({WCA[`DIVLEN+2:0], 1'b0}, {(`DIVLEN+4){1'b0}}, Start, WCN);
flop #(Nf+4) wcflop(clk, WCN, WC); flop #(`DIVLEN+4) wcflop(clk, WCN, WC);
flopen #(Nf+4) dflop(clk, Start, {4'b0001, Dpreproc}, D); flopen #(`DIVLEN+4) dflop(clk, Start, {4'b0001, Dpreproc}, D);
// Quotient Selection logic // Quotient Selection logic
// Given partial remainder, select quotient of +1, 0, or -1 (qp, qz, pm) // Given partial remainder, select quotient of +1, 0, or -1 (qp, qz, pm)
// Accumulate quotient digits in a shift register qsel2 qsel2(WS[`DIVLEN+3:`DIVLEN], WC[`DIVLEN+3:`DIVLEN], qp, qz, qm);
qsel #(Nf) qsel(WS[55:52], WC[55:52], qp, qz, qm); // Accumulate quotient digits in a shift register (now done in OTFC)
qacc #(Nf+3) qacc(clk, Start, qp, qz, qm, rp, rm); qacc #(`DIVLEN+3) qacc(clk, Start, qp, qz, qm, rp, rm);
flopen #(`NE) expflop(clk, Start, calcExp, rExp); flopen #(`NE) expflop(clk, Start, calcExp, rExp);
flopen #(1) signflop(clk, Start, calcSign, rsign); flopen #(1) signflop(clk, Start, calcSign, rsign);
// Divisor Selection logic // Divisor Selection logic
inv dinv(D, Db); inv dinv(D, Db);
mux3onehot divisorsel(Db, 56'b0, D, qp, qz, qm, Dsel); mux3onehot #(`DIVLEN) divisorsel(Db, {(`DIVLEN+4){1'b0}}, D, qp, qz, qm, Dsel);
// Partial Product Generation // Partial Product Generation
csa csa(WS, WC, Dsel, qp, WSA, WCA); csa #(`DIVLEN+4) csa(WS, WC, Dsel, qp, WSA, WCA);
otfc2 otfc2(clk, Start, qp, qz, qm, QuotOTFC); otfc2 #(`DIVLEN) otfc2(clk, Start, qp, qz, qm, QuotOTFC);
expcalc expcalc(.XExp, .YExp, .calcExp); expcalc expcalc(.XExp, .YExp, .calcExp);
@ -95,70 +101,60 @@ module srt #(parameter Nf=52) (
srtpostproc postproc(rp, rm, Quot); srtpostproc postproc(rp, rm, Quot);
endmodule endmodule
module srtpostproc #(parameter N=52) ( ////////////////
input [N+2:0] rp, rm, // Submodules //
output [N-1:0] Quot ////////////////
);
//assign Quot = rp - rm; ///////////////////
finaladd finaladd(rp, rm, Quot); // Preprocessing //
endmodule ///////////////////
module srtpreproc (
module srtpreproc #(parameter Nf=52) (
input logic [`XLEN-1:0] SrcA, SrcB, input logic [`XLEN-1:0] SrcA, SrcB,
input logic [Nf-1:0] SrcXFrac, SrcYFrac, input logic [`NF-1:0] SrcXFrac, SrcYFrac,
input logic [1:0] Fmt, // Floats: 00 = 16 bit, 01 = 32 bit, 10 = 64 bit, 11 = 128 bit input logic [1:0] Fmt, // Floats: 00 = 16 bit, 01 = 32 bit, 10 = 64 bit, 11 = 128 bit
input logic W64, // 32-bit ints on XLEN=64 input logic W64, // 32-bit ints on XLEN=64
input logic Signed, // Interpret integers as signed 2's complement input logic Signed, // Interpret integers as signed 2's complement
input logic Int, // Choose integer inputss input logic Int, // Choose integer inputs
input logic Sqrt, // perform square root, not divide input logic Sqrt, // perform square root, not divide
output logic [Nf-1:0] X, D output logic [`DIVLEN-1:0] X, D,
output logic [$clog2(`XLEN+1)-1:0] intExp, // Quotient integer exponent
output logic intSign // Quotient integer sign
); );
// Initial: just pass X and Y through for simple fp division logic [$clog2(`XLEN+1)-1:0] zeroCntA, zeroCntB;
assign X = SrcXFrac; logic [`XLEN-1:0] PosA, PosB;
assign D = SrcYFrac; logic [`DIVLEN-1:0] ExtraA, ExtraB, PreprocA, PreprocB, PreprocX, PreprocY;
assign PosA = (Signed & SrcA[`XLEN - 1]) ? -SrcA : SrcA;
assign PosB = (Signed & SrcB[`XLEN - 1]) ? -SrcB : SrcB;
lzc #(`XLEN) lzcA (PosA, zeroCntA);
lzc #(`XLEN) lzcB (PosB, zeroCntB);
assign ExtraA = {1'b0, PosA, {`EXTRAINTBITS{1'b0}}};
assign ExtraB = {1'b0, PosB, {`EXTRAINTBITS{1'b0}}};
assign PreprocA = ExtraA << zeroCntA;
assign PreprocB = ExtraB << (zeroCntB + 1);
assign PreprocX = {SrcXFrac, {`EXTRAFRACBITS{1'b0}}};
assign PreprocY = {SrcYFrac, {`EXTRAFRACBITS{1'b0}}};
assign X = Int ? PreprocA : PreprocX;
assign D = Int ? PreprocB : PreprocY;
assign intExp = zeroCntB - zeroCntA + 1;
assign intSign = Signed & (SrcA[`XLEN - 1] ^ SrcB[`XLEN - 1]);
endmodule endmodule
/* /////////////////////////////////
// Quotient Selection, Radix 2 //
////////// /////////////////////////////////
// mux2 // module qsel2 ( // *** eventually just change to 4 bits
////////// input logic [`DIVLEN+3:`DIVLEN] ps, pc,
module mux2(input logic [55:0] in0, in1,
input logic sel,
output logic [55:0] out);
assign #1 out = sel ? in1 : in0;
endmodule
//////////
// flop //
//////////
module flop(clk, in, out);
input clk;
input [55:0] in;
output [55:0] out;
logic [55:0] state;
always @(posedge clk)
state <= #1 in;
assign #1 out = state;
endmodule
*/
//////////
// qsel //
//////////
module qsel #(parameter Nf=52) ( // *** eventually just change to 4 bits
input logic [Nf+3:Nf] ps, pc,
output logic qp, qz, qm output logic qp, qz, qm
); );
logic [Nf+3:Nf] p, g; logic [`DIVLEN+3:`DIVLEN] p, g;
logic magnitude, sign, cout; logic magnitude, sign, cout;
// The quotient selection logic is presented for simplicity, not // The quotient selection logic is presented for simplicity, not
@ -169,9 +165,9 @@ module qsel #(parameter Nf=52) ( // *** eventually just change to 4 bits
assign p = ps ^ pc; assign p = ps ^ pc;
assign g = ps & pc; assign g = ps & pc;
assign #1 magnitude = ~(&p[54:52]); assign #1 magnitude = ~(&p[`DIVLEN+2:`DIVLEN]);
assign #1 cout = g[54] | (p[54] & (g[53] | p[53] & g[52])); assign #1 cout = g[`DIVLEN+2] | (p[`DIVLEN+2] & (g[`DIVLEN+1] | p[`DIVLEN+1] & g[`DIVLEN]));
assign #1 sign = p[55] ^ cout; assign #1 sign = p[`DIVLEN+3] ^ cout;
/* assign #1 magnitude = ~((ps[54]^pc[54]) & (ps[53]^pc[53]) & /* assign #1 magnitude = ~((ps[54]^pc[54]) & (ps[53]^pc[53]) &
(ps[52]^pc[52])); (ps[52]^pc[52]));
assign #1 sign = (ps[55]^pc[55])^ assign #1 sign = (ps[55]^pc[55])^
@ -188,15 +184,16 @@ endmodule
////////// //////////
// qacc // // qacc //
////////// //////////
module qacc #(parameter N=55) ( // To be replaced by OTFC
module qacc #(parameter N=68) (
input logic clk, input logic clk,
input logic req, input logic req,
input logic qp, qz, qm, input logic qp, qz, qm,
output logic [N-1:0] rp, rm output logic [N-1:0] rp, rm
); );
flopr #(N) rmreg(clk, req, {rm[53:0], qm}, rm); flopr #(N) rmreg(clk, req, {rm[N-2:0], qm}, rm);
flopr #(N) rpreg(clk, req, {rp[53:0], qp}, rp); flopr #(N) rpreg(clk, req, {rp[N-2:0], qp}, rp);
/* always @(posedge clk) /* always @(posedge clk)
begin begin
if (req) if (req)
@ -212,11 +209,10 @@ module qacc #(parameter N=55) (
end */ end */
endmodule endmodule
////////// ///////////////////////////////////
// otfc // // On-The-Fly Converter, Radix 2 //
////////// ///////////////////////////////////
module otfc2 #(parameter N=65) (
module otfc2 #(parameter N=52) (
input logic clk, input logic clk,
input logic Start, input logic Start,
input logic qp, qz, qm, input logic qp, qz, qm,
@ -255,16 +251,15 @@ module otfc2 #(parameter N=52) (
QMNext = {QMR, 1'b0}; QMNext = {QMR, 1'b0};
end end
end end
assign r = Q[54] ? Q[53:2] : Q[52:1]; assign r = Q[N+2] ? Q[N+1:2] : Q[N:1];
endmodule endmodule
///////// /////////
// inv // // inv //
///////// /////////
module inv(input logic [`DIVLEN+3:0] in,
module inv(input logic [55:0] in, output logic [`DIVLEN+3:0] out);
output logic [55:0] out);
assign #1 out = ~in; assign #1 out = ~in;
endmodule endmodule
@ -272,14 +267,11 @@ endmodule
////////// //////////
// mux3 // // mux3 //
////////// //////////
module mux3onehot(in0, in1, in2, sel0, sel1, sel2, out); module mux3onehot #(parameter N=65) (
input [55:0] in0; input logic [N+3:0] in0, in1, in2,
input [55:0] in1; input logic sel0, sel1, sel2,
input [55:0] in2; output logic [N+3:0] out
input sel0; );
input sel1;
input sel2;
output [55:0] out;
// lazy inspection of the selects // lazy inspection of the selects
// really we should make sure selects are mutually exclusive // really we should make sure selects are mutually exclusive
@ -290,7 +282,7 @@ endmodule
///////// /////////
// csa // // csa //
///////// /////////
module csa #(parameter N=56) ( module csa #(parameter N=69) (
input logic [N-1:0] in1, in2, in3, input logic [N-1:0] in1, in2, in3,
input logic cin, input logic cin,
output logic [N-1:0] out1, out2 output logic [N-1:0] out1, out2
@ -305,28 +297,26 @@ module csa #(parameter N=56) (
// insert cin. // insert cin.
assign #1 out1 = in1 ^ in2 ^ in3; assign #1 out1 = in1 ^ in2 ^ in3;
assign #1 out2 = {in1[54:0] & (in2[54:0] | in3[54:0]) | assign #1 out2 = {in1[N-2:0] & (in2[N-2:0] | in3[N-2:0]) |
(in2[54:0] & in3[54:0]), cin}; (in2[N-2:0] & in3[N-2:0]), cin};
endmodule endmodule
////////////// //////////////
// expcalc // // expcalc //
////////////// //////////////
module expcalc( module expcalc(
input logic [`NE-1:0] XExp, YExp, input logic [`NE-1:0] XExp, YExp,
output logic [`NE-1:0] calcExp output logic [`NE-1:0] calcExp
); );
assign calcExp = XExp - YExp + 11'b01111111111; assign calcExp = XExp - YExp + (`NE)'(`BIAS);
endmodule endmodule
////////////// //////////////
// signcalc // // signcalc //
////////////// //////////////
module signcalc( module signcalc(
input logic XSign, YSign, input logic XSign, YSign,
output logic calcSign output logic calcSign
@ -336,15 +326,27 @@ module signcalc(
endmodule endmodule
////////////////////
// Postprocessing //
////////////////////
module srtpostproc (
input [`DIVLEN+2:0] rp, rm,
output [`DIVLEN-1:0] Quot
);
//assign Quot = rp - rm;
finaladd #(`DIVLEN+3) finaladd(rp, rm, Quot);
endmodule
////////////// //////////////
// finaladd // // finaladd //
////////////// //////////////
module finaladd( module finaladd #(parameter N=68) (
input logic [54:0] rp, rm, input logic [N-1:0] rp, rm,
output logic [51:0] r output logic [N-4:0] r
); );
logic [54:0] diff; logic [N-1:0] diff;
// this magic block performs the final addition for you // this magic block performs the final addition for you
// to convert the positive and negative quotient digits // to convert the positive and negative quotient digits
@ -359,6 +361,6 @@ module finaladd(
// The checker ignores such an error. // The checker ignores such an error.
assign #1 diff = rp - rm; assign #1 diff = rp - rm;
assign #1 r = diff[54] ? diff[53:2] : diff[52:1]; assign #1 r = diff[N-1] ? diff[N-2:2] : diff[N-3:1];
endmodule endmodule

27
pipelined/srt/testbench.sv
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@ -1,3 +1,5 @@
`define DIVLEN 65
///////////// /////////////
// counter // // counter //
///////////// /////////////
@ -37,15 +39,16 @@ endmodule
// testbench // // testbench //
////////// //////////
module testbench; module testbench;
logic clk; logic clk;
logic req; logic req;
logic done; logic done;
logic [63:0] a, b; logic [63:0] a, b;
logic [51:0] afrac, bfrac; logic [51:0] afrac, bfrac;
logic [10:0] aExp, bExp; logic [10:0] aExp, bExp;
logic asign, bsign; logic asign, bsign;
logic [51:0] r, rOTFC; logic [51:0] r, rOTFC;
logic [54:0] rp, rm; // positive quotient digits logic [`DIVLEN-1:0] Quot, QuotOTFC;
logic [54:0] rp, rm; // positive quotient digits
// Test parameters // Test parameters
parameter MEM_SIZE = 40000; parameter MEM_SIZE = 40000;
@ -65,14 +68,14 @@ module testbench;
integer testnum, errors; integer testnum, errors;
// Divider // Divider
srt #(52) srt(.clk, .Start(req), srt srt(.clk, .Start(req),
.Stall(1'b0), .Flush(1'b0), .Stall(1'b0), .Flush(1'b0),
.XExp(aExp), .YExp(bExp), .rExp, .XExp(aExp), .YExp(bExp), .rExp,
.XSign(asign), .YSign(bsign), .rsign, .XSign(asign), .YSign(bsign), .rsign,
.SrcXFrac(afrac), .SrcYFrac(bfrac), .SrcXFrac(afrac), .SrcYFrac(bfrac),
.SrcA('0), .SrcB('0), .Fmt(2'b00), .SrcA('0), .SrcB('0), .Fmt(2'b00),
.W64(1'b0), .Signed(1'b0), .Int(1'b0), .Sqrt(1'b0), .W64(1'b0), .Signed(1'b0), .Int(1'b0), .Sqrt(1'b0),
.Quot(r), .QuotOTFC(rOTFC), .Rem(), .Flags()); .Quot, .QuotOTFC, .Rem(), .Flags());
// Counter // Counter
counter counter(clk, req, done); counter counter(clk, req, done);
@ -98,6 +101,8 @@ module testbench;
b = Vec[`memb]; b = Vec[`memb];
{bsign, bExp, bfrac} = b; {bsign, bExp, bfrac} = b;
nextr = Vec[`memr]; nextr = Vec[`memr];
r = Quot[`DIVLEN:`DIVLEN - 52];
rOTFC = QuotOTFC[`DIVLEN:`DIVLEN - 52];
req <= #5 1; req <= #5 1;
end end