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DIVLEN and counter updated for sqrt computation and rounding

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This commit is contained in:
cturek 2022-07-13 22:42:39 +00:00
parent 7e163e22a3
commit 7629173b15
3 changed files with 14 additions and 25 deletions
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2
pipelined/config/shared/wally-shared.vh
View File

@ -103,7 +103,7 @@
// division constants
`define RADIX 32'h4
`define DIVCOPIES 32'h4
`define DIVLEN ((`NF < `XLEN) ? (`XLEN) : (`NF + 1))
`define DIVLEN ((`NF < `XLEN) ? (`XLEN + 2) : (`NF + 2))
`define DIVRESLEN ((`NF>`XLEN) ? `DIVLEN+2 : `DIVLEN)
`define LOGR ((`RADIX==2) ? 32'h1 : 32'h2)
// FPDUR = ceil(DIVRESLEN/(LOGR*DIVCOPIES))

2
pipelined/srt/srt-waves.do
View File

@ -1,5 +1,5 @@
add wave -noupdate /testbench/*
add wave -noupdate /testbench/srt/*
add wave -noupdate /testbench/srt/otfc2/*
add wave -noupdate /testbench/srt/sotfc2/*
add wave -noupdate /testbench/srt/preproc/*
add wave -noupdate /testbench/srt/divcounter/*

35
pipelined/srt/srt.sv
View File

@ -29,8 +29,8 @@
////////////////////////////////////////////////////////////////////////////////////////////////
`include "wally-config.vh"
`define EXTRAFRACBITS ((`NF<(`XLEN)) ? (`XLEN - `NF) : 0)
`define EXTRAINTBITS ((`NF<(`XLEN)) ? 0 : (`NF - `XLEN + 1))
`define EXTRAFRACBITS ((`NF<(`XLEN)) ? (`XLEN - `NF + 2) : 2)
`define EXTRAINTBITS ((`NF<(`XLEN)) ? 2 : (`NF - `XLEN + 2))
module srt (
input logic clk,
@ -49,7 +49,7 @@ module srt (
input logic Int, // Choose integer inputs
input logic Sqrt, // perform square root, not divide
output logic rsign, done,
output logic [`DIVLEN-1:0] Rem, Quot, // *** later handle integers
output logic [`DIVLEN-3:0] Rem, Quot, // *** later handle integers
output logic [`NE-1:0] rExp,
output logic [3:0] Flags
);
@ -164,7 +164,7 @@ module srtpreproc (
assign intSign = Signed & (SrcA[`XLEN - 1] ^ SrcB[`XLEN - 1]);
// Number of cycles of divider
assign dur = Int ? (intExp & {7{~intExp[6]}}) : (7)'(`DIVLEN + 2);
assign dur = Int ? (intExp & {7{~intExp[6]}}) : (7)'(`DIVLEN);
endmodule
/////////////////////////////////
@ -226,26 +226,16 @@ endmodule
///////////////////////////////////
// On-The-Fly Converter, Radix 2 //
///////////////////////////////////
module otfc2 #(parameter N=64) (
module otfc2 #(parameter N=66) (
input logic clk,
input logic Start,
input logic qp, qz, qn,
output logic [N-1:0] r
output logic [N-3:0] r
);
// The on-the-fly converter transfers the quotient
// bits to the quotient as they come.
//
// This code follows the psuedocode presented in the
// floating point chapter of the book. Right now,
// it is written for Radix-2 division.
//
// QM is Q-1. It allows us to write negative bits
// without using a costly CPA.
// bits to the quotient as they come.
// Use this otfc for division only.
logic [N+2:0] Q, QM, QNext, QMNext, QMMux;
// QR and QMR are the shifted versions of Q and QM.
// They are treated as [N-1:r] size signals, and
// discard the r most significant bits of Q and QM.
logic [N+1:0] QR, QMR;
flopr #(N+3) Qreg(clk, Start, QNext, Q);
@ -266,7 +256,7 @@ module otfc2 #(parameter N=64) (
QMNext = {QMR, 1'b0};
end
end
assign r = Q[N+2] ? Q[N+1:2] : Q[N:1];
assign r = Q[N] ? Q[N-1:2] : Q[N-2:1];
endmodule
@ -278,13 +268,12 @@ module sotfc2(
input logic Start,
input logic sp, sn,
input logic [`DIVLEN+3:0] C,
output logic [`DIVLEN-1:0] Sq,
output logic [`DIVLEN-3:0] Sq,
output logic [`DIVLEN+3:0] F
);
// The on-the-fly converter transfers the square root
// bits to the quotient as they come.
// Use this otfc for division and square root.
logic [`DIVLEN+3:0] S, SM, SNext, SMNext, SMux;
flopr #(`DIVLEN+4) Sreg(clk, Start, SMNext, SM);
@ -303,7 +292,7 @@ module sotfc2(
SMNext = SM | ((C << 2) & ~(C << 1));
end
end
assign Sq = S[`DIVLEN-1:0];
assign Sq = S[`DIVLEN] ? S[`DIVLEN-1:2] : S[`DIVLEN-2:1];
fsel2 fsel(sp, sn, C, S, SM, F);