forked from Github_Repos/cvw
73 lines
2.5 KiB
Systemverilog
73 lines
2.5 KiB
Systemverilog
///////////////////////////////////////////
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// fdivsqrtpreproc.sv
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//
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// Written: David_Harris@hmc.edu, me@KatherineParry.com, cturek@hmc.edu
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// Modified:13 January 2022
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//
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// Purpose: Combined Divide and Square Root Floating Point and Integer Unit
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//
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// A component of the Wally configurable RISC-V project.
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//
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// Copyright (C) 2021-23 Harvey Mudd College & Oklahoma State University
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//
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// SPDX-License-Identifier: Apache-2.0 WITH SHL-2.1
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//
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// Licensed under the Solderpad Hardware License v 2.1 (the “License”); you may not use this file
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// except in compliance with the License, or, at your option, the Apache License version 2.0. You
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// may obtain a copy of the License at
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//
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// https://solderpad.org/licenses/SHL-2.1/
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//
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// Unless required by applicable law or agreed to in writing, any work distributed under the
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// License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
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// either express or implied. See the License for the specific language governing permissions
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// and limitations under the License.
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////////////////////////////////////////////////////////////////////////////////////////////////
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`include "wally-config.vh"
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module fdivsqrtexpcalc(
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input logic [`FMTBITS-1:0] Fmt,
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input logic [`NE-1:0] Xe, Ye,
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input logic Sqrt,
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input logic XZero,
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input logic [`DIVBLEN:0] ell, m,
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output logic [`NE+1:0] Qe
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);
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logic [`NE-2:0] Bias;
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logic [`NE+1:0] SXExp;
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logic [`NE+1:0] SExp;
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logic [`NE+1:0] DExp;
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if (`FPSIZES == 1) begin
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assign Bias = (`NE-1)'(`BIAS);
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end else if (`FPSIZES == 2) begin
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assign Bias = Fmt ? (`NE-1)'(`BIAS) : (`NE-1)'(`BIAS1);
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end else if (`FPSIZES == 3) begin
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always_comb
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case (Fmt)
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`FMT: Bias = (`NE-1)'(`BIAS);
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`FMT1: Bias = (`NE-1)'(`BIAS1);
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`FMT2: Bias = (`NE-1)'(`BIAS2);
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default: Bias = 'x;
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endcase
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end else if (`FPSIZES == 4) begin
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always_comb
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case (Fmt)
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2'h3: Bias = (`NE-1)'(`Q_BIAS);
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2'h1: Bias = (`NE-1)'(`D_BIAS);
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2'h0: Bias = (`NE-1)'(`S_BIAS);
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2'h2: Bias = (`NE-1)'(`H_BIAS);
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endcase
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end
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assign SXExp = {2'b0, Xe} - {{(`NE+1-`DIVBLEN){1'b0}}, ell} - (`NE+2)'(`BIAS);
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assign SExp = {SXExp[`NE+1], SXExp[`NE+1:1]} + {2'b0, Bias};
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// correct exponent for Subnormalized input's normalization shifts
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assign DExp = ({2'b0, Xe} - {{(`NE+1-`DIVBLEN){1'b0}}, ell} - {2'b0, Ye} + {{(`NE+1-`DIVBLEN){1'b0}}, m} + {3'b0, Bias}) & {`NE+2{~XZero}};
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assign Qe = Sqrt ? SExp : DExp;
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endmodule
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