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Commented out unused comparators

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David Harris 2022-08-22 08:28:28 +00:00
parent 617dc02d01
commit b91f33372e
1 changed files with 28 additions and 22 deletions
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50
pipelined/src/ieu/comparator.sv
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@ -30,6 +30,29 @@
`include "wally-config.vh"
// This comparator is best
module comparator_dc_flip #(parameter WIDTH=64) (
input logic [WIDTH-1:0] a, b,
input logic sgnd,
output logic [1:0] flags);
logic eq, lt, ltu;
logic [WIDTH-1:0] af, bf;
// For signed numbers, flip most significant bit
assign af = {a[WIDTH-1] ^ sgnd, a[WIDTH-2:0]};
assign bf = {b[WIDTH-1] ^ sgnd, b[WIDTH-2:0]};
// behavioral description gives best results
assign eq = (a == b);
assign lt = (af < bf);
assign flags = {eq, lt};
endmodule
/*
Other comparators evaluated
module donedet #(parameter WIDTH=64) (
input logic [WIDTH-1:0] a, b,
output logic eq);
@ -80,24 +103,6 @@ module comparator #(parameter WIDTH=64) (
assign flags = {eq, lt, ltu};
endmodule
// This comparator is best
module comparator_dc_flip #(parameter WIDTH=64) (
input logic [WIDTH-1:0] a, b,
input logic sgnd,
output logic [1:0] flags);
logic eq, lt, ltu;
logic [WIDTH-1:0] af, bf;
// For signed numbers, flip most significant bit
assign af = {a[WIDTH-1] ^ sgnd, a[WIDTH-2:0]};
assign bf = {b[WIDTH-1] ^ sgnd, b[WIDTH-2:0]};
// behavioral description gives best results
assign eq = (a == b);
assign lt = (af < bf);
assign flags = {eq, lt};
endmodule
module comparator2 #(parameter WIDTH=64) (
input logic clk, reset,
@ -106,7 +111,7 @@ module comparator2 #(parameter WIDTH=64) (
logic eq, lt, ltu;
/* verilator lint_off UNOPTFLAT */
/* verilator lint_off UNOPTFLAT /
// prefix implementation
localparam levels=$clog2(WIDTH);
genvar i;
@ -133,7 +138,7 @@ module comparator2 #(parameter WIDTH=64) (
// A < B signed if less than unsigned and msb is not < unsigned, or if A negative and B positive
assign lt2 = ltu2 & ~l[0][WIDTH-1] | a[WIDTH-1] & ~b[WIDTH-1];
assign flags = {eq2, lt2, ltu2};
/* verilator lint_on UNOPTFLAT */
/* verilator lint_on UNOPTFLAT /
endmodule
@ -143,7 +148,7 @@ module comparator_prefix #(parameter WIDTH=64) (
logic eq, lt, ltu;
/* verilator lint_off UNOPTFLAT */
/* verilator lint_off UNOPTFLAT
// prefix implementation
localparam levels=$clog2(WIDTH);
genvar i;
@ -170,7 +175,7 @@ module comparator_prefix #(parameter WIDTH=64) (
// A < B signed if less than unsigned and msb is not < unsigned, or if A negative and B positive
assign lt2 = ltu2 & ~l[0][WIDTH-1] | a[WIDTH-1] & ~b[WIDTH-1];
assign flags = {eq2, lt2, ltu2};
/* verilator lint_on UNOPTFLAT */
/* verilator lint_on UNOPTFLAT /
endmodule
@ -317,3 +322,4 @@ module stinecomp64 (FCC, A, B, Sel);
assign FCC = {LT, EQ};
endmodule // comp64
*/