From c7050ada78194bf857d578212aa8445fc253cf7e Mon Sep 17 00:00:00 2001 From: Kevin Kim Date: Fri, 24 Feb 2023 17:33:47 -0800 Subject: [PATCH] removed old shifter --- src/ieu/alu.sv | 4 +- src/ieu/shifter.sv | 121 ++++++++++++------------------------------ src/ieu/shifternew.sv | 85 ----------------------------- 3 files changed, 35 insertions(+), 175 deletions(-) delete mode 100644 src/ieu/shifternew.sv diff --git a/src/ieu/alu.sv b/src/ieu/alu.sv index 1fdd06e4..96d8c8f5 100644 --- a/src/ieu/alu.sv +++ b/src/ieu/alu.sv @@ -55,7 +55,7 @@ module alu #(parameter WIDTH=32) ( logic Asign, Bsign; // Sign bits of A, B logic Rotate; logic [WIDTH:0] shA; // XLEN+1 bit input source to shifter - logic [WIDTH-1:0] rotA; // XLEN bit input source to shifter + logic [WIDTH-1:0] rotA; // XLEN bit input source to shifter if (`ZBS_SUPPORTED) begin: zbsdec @@ -85,7 +85,7 @@ module alu #(parameter WIDTH=32) ( // Pre-Shift Mux always_comb case (Funct3[2:1] & {2{BSelect[3]}}) - 2'b00: CondShiftA = shA[63:0]; + 2'b00: CondShiftA = shA[WIDTH-1:0]; 2'b01: CondShiftA = {shA[WIDTH-2:0],{1'b0}}; // sh1add 2'b10: CondShiftA = {shA[WIDTH-3:0],{2'b00}}; // sh2add 2'b11: CondShiftA = {shA[WIDTH-4:0],{3'b000}}; // sh3add diff --git a/src/ieu/shifter.sv b/src/ieu/shifter.sv index feb346ef..f6cb5bc1 100644 --- a/src/ieu/shifter.sv +++ b/src/ieu/shifter.sv @@ -1,7 +1,7 @@ /////////////////////////////////////////// // shifter.sv // -// Written: David_Harris@hmc.edu, Sarah.Harris@unlv.edu, kekim@hmc.edu +// Written: David_Harris@hmc.edu, Sarah.Harris@unlv.edu, Kevin Kim // Created: 9 January 2021 // Modified: 6 February 2023 // @@ -29,111 +29,56 @@ `include "wally-config.vh" -module shifter ( - input logic [`XLEN-1:0] A, // Source +module shifternew ( + input logic [`XLEN:0] shA, // shift Source + input logic [`XLEN-1:0] rotA, // rotate source input logic [`LOG_XLEN-1:0] Amt, // Shift amount - input logic Right, Arith, W64, Rotate, // Shift right, arithmetic, RV64 W-type shift + input logic Right, Rotate, W64, // Shift right, rotate signals output logic [`XLEN-1:0] Y); // Shifted result logic [2*`XLEN-2:0] z, zshift; // Input to funnel shifter, shifted amount before truncated to 32 or 64 bits - logic [`LOG_XLEN-1:0] amttrunc, offset, CondOffsetTrunc; // Shift amount adjusted for RV64, right-shift amount + logic [`LOG_XLEN-1:0] amttrunc, offset; // Shift amount adjusted for RV64, right-shift amount - // Handle left and right shifts with a funnel shifter. - // For RV32, only 32-bit shifts are needed. - // For RV64, 32- and 64-bit shifts are needed, with sign extension. - /* - // Funnel shifter input (see CMOS VLSI Design 4e Section 11.8.1, note Table 11.11 shift types wrong) - if (`XLEN==32) begin:shifter // RV32 - always_comb // funnel mux - if (Right) - if (Arith) z = {{31{A[31]}}, A}; - else z = {31'b0, A}; - else z = {A, 31'b0}; - assign amttrunc = Amt; // shift amount - end else begin:shifter // RV64 - always_comb // funnel mux - if (W64) begin // 32-bit shifts - if (Right) - if (Arith) z = {64'b0, {31{A[31]}}, A[31:0]}; - else z = {95'b0, A[31:0]}; - else z = {32'b0, A[31:0], 63'b0}; - end else begin - if (Right) - if (Arith) z = {{63{A[63]}}, A}; - else z = {63'b0, A}; - else z = {A, 63'b0}; - end - assign amttrunc = W64 ? {1'b0, Amt[4:0]} : Amt; // 32- or 64-bit shift - end - */ - if (`ZBB_SUPPORTED) begin: rotFunnel // HANDLES ROTATE + if (`ZBB_SUPPORTED) begin: rotfunnel + if (`XLEN==32) begin // rv32 with rotates + always_comb // funnel mux + case({Right, Rotate}) + 2'b00: z = {shA[31:0], 31'b0}; + 2'b01: z = {rotA,rotA[31:1]}; + 2'b10: z = {{31{shA[32]}}, shA[31:0]}; + 2'b11: z = {rotA[30:0],rotA}; + endcase + assign amttrunc = Amt; // shift amount + end else begin // rv64 with rotates + always_comb // funnel mux + case ({Right, Rotate}) + 2'b00: z = {shA[63:0],{63'b0}}; + 2'b01: z = {rotA, rotA[63:1]}; + 2'b10: z = {{63{shA[64]}},shA[63:0]}; + 2'b11: z = {rotA[62:0],rotA[63:0]}; + endcase + assign amttrunc = W64 ? {1'b0, Amt[4:0]} : Amt; // 32- or 64-bit shift + end + end else begin: norotfunnel if (`XLEN==32) begin:shifter // RV32 always_comb // funnel mux - if (Right) - if (Rotate) z = {A[30:0], A[31:0]}; //ror (rv32) - else - if (Arith) z = {{31{A[31]}}, A}; - else z = {31'b0, A}; - else - if (Rotate) z = {A[31:0], A[31:1]}; //rol (rv32) - else z = {A, 31'b0}; + if (Right) z = {{31{shA[32]}}, shA[31:0]}; + else z = {shA[31:0], 31'b0}; assign amttrunc = Amt; // shift amount end else begin:shifter // RV64 always_comb // funnel mux - if (W64) begin // 32-bit shifts - if (Right) - if (Rotate) z = {{64'b0},A[30:0],A[31:0]}; //rorw - else - if (Arith) z = {64'b0, {31{A[31]}}, A[31:0]}; - else z = {95'b0, A[31:0]}; - else - if (Rotate) z = {{64'b0},A[31:0],A[31:1]}; //rolw - else z = {32'b0, A[31:0], 63'b0}; - end else begin - if (Right) - if (Rotate) z = {A[62:0], A[63:0]}; //ror - else - if (Arith) z = {{63{A[63]}}, A}; - else z = {63'b0, A}; - else - if (Rotate) z = {A[63:0], A[63:1]}; //rol - else z = {A, 63'b0}; - end - assign amttrunc = W64 ? {1'b0, Amt[4:0]} : Amt; // 32- or 64-bit shift - end - end else begin: norotFunnel - if (`XLEN==32) begin:shifter // RV32 - always_comb // funnel mux - if (Right) - if (Arith) z = {{31{A[31]}}, A}; - else z = {31'b0, A}; - else z = {A, 31'b0}; - assign amttrunc = Amt; // shift amount - end else begin:shifter // RV64 - always_comb // funnel mux - if (W64) begin // 32-bit shifts - if (Right) - if (Arith) z = {64'b0, {31{A[31]}}, A[31:0]}; - else z = {95'b0, A[31:0]}; - else z = {32'b0, A[31:0], 63'b0}; - end else begin - if (Right) - if (Arith) z = {{63{A[63]}}, A}; - else z = {63'b0, A}; - else z = {A, 63'b0}; - end + if (Right) z = {{63{shA[64]}},shA[63:0]}; + else z = {shA[63:0],{63'b0}}; assign amttrunc = W64 ? {1'b0, Amt[4:0]} : Amt; // 32- or 64-bit shift end end - + // Opposite offset for right shifts assign offset = Right ? amttrunc : ~amttrunc; - if (`XLEN == 64) assign CondOffsetTrunc = (W64 & Rotate) ? {{1'b0}, offset[4:0]} : offset; - else assign CondOffsetTrunc = offset; // Funnel operation - assign zshift = z >> CondOffsetTrunc; + assign zshift = z >> offset; assign Y = zshift[`XLEN-1:0]; endmodule diff --git a/src/ieu/shifternew.sv b/src/ieu/shifternew.sv deleted file mode 100644 index e58a1277..00000000 --- a/src/ieu/shifternew.sv +++ /dev/null @@ -1,85 +0,0 @@ -/////////////////////////////////////////// -// shifter.sv -// -// Written: David_Harris@hmc.edu, Sarah.Harris@unlv.edu, kekim@hmc.edu -// Created: 9 January 2021 -// Modified: 6 February 2023 -// -// Purpose: RISC-V 32/64 bit shifter -// -// Documentation: RISC-V System on Chip Design Chapter 4 (Figure 4.5, Table 4.3) -// -// A component of the CORE-V-WALLY configurable RISC-V project. -// -// Copyright (C) 2021-23 Harvey Mudd College & Oklahoma State University -// -// SPDX-License-Identifier: Apache-2.0 WITH SHL-2.1 -// -// Licensed under the Solderpad Hardware License v 2.1 (the “License”); you may not use this file -// except in compliance with the License, or, at your option, the Apache License version 2.0. You -// may obtain a copy of the License at -// -// https://solderpad.org/licenses/SHL-2.1/ -// -// Unless required by applicable law or agreed to in writing, any work distributed under the -// License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, -// either express or implied. See the License for the specific language governing permissions -// and limitations under the License. -//////////////////////////////////////////////////////////////////////////////////////////////// - -`include "wally-config.vh" - -module shifternew ( - input logic [`XLEN:0] shA, // shift Source - input logic [`XLEN-1:0] rotA, // rotate source - input logic [`LOG_XLEN-1:0] Amt, // Shift amount - input logic Right, Rotate, W64, // Shift right, rotate signals - output logic [`XLEN-1:0] Y); // Shifted result - - logic [2*`XLEN-2:0] z, zshift; // Input to funnel shifter, shifted amount before truncated to 32 or 64 bits - logic [`LOG_XLEN-1:0] amttrunc, offset; // Shift amount adjusted for RV64, right-shift amount - - - if (`ZBB_SUPPORTED) begin: rotfunnel - if (`XLEN==32) begin // rv32 with rotates - always_comb // funnel mux - case({Right, Rotate}) - 2'b00: z = {shA[31:0], 31'b0}; - 2'b01: z = {rotA,rotA[31:1]}; - 2'b10: z = {{31{shA[32]}}, shA[31:0]}; - 2'b11: z = {rotA[30:0],rotA}; - endcase - assign amttrunc = Amt; // shift amount - end else begin // rv64 with rotates - always_comb // funnel mux - case ({Right, Rotate}) - 2'b00: z = {shA[63:0],{63'b0}}; - 2'b01: z = {rotA, rotA[63:1]}; - 2'b10: z = {{63{shA[64]}},shA[63:0]}; - 2'b11: z = {rotA[62:0],rotA[63:0]}; - endcase - assign amttrunc = W64 ? {1'b0, Amt[4:0]} : Amt; // 32- or 64-bit shift - end - end else begin: norotfunnel - if (`XLEN==32) begin:shifter // RV32 - always_comb // funnel mux - if (Right) z = {{31{shA[32]}}, shA[31:0]}; - else z = {shA[31:0], 31'b0}; - assign amttrunc = Amt; // shift amount - end else begin:shifter // RV64 - always_comb // funnel mux - if (Right) z = {{63{shA[64]}},shA[63:0]}; - else z = {shA[63:0],{63'b0}}; - assign amttrunc = W64 ? {1'b0, Amt[4:0]} : Amt; // 32- or 64-bit shift - end - end - - // Opposite offset for right shifts - assign offset = Right ? amttrunc : ~amttrunc; - - // Funnel operation - assign zshift = z >> offset; - assign Y = zshift[`XLEN-1:0]; -endmodule - -