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// $Id: aeMB_regf.v,v 1.3 2007/11/10 16:39:38 sybreon Exp $
//
// AEMB REGISTER FILE
//
// Copyright (C) 2004-2007 Shawn Tan Ser Ngiap <shawn.tan@aeste.net>
//
// This file is part of AEMB.
//
// AEMB is free software: you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// AEMB is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
// Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with AEMB. If not, see <http://www.gnu.org/licenses/>.
//
// $Log: aeMB_regf.v,v $
// Revision 1.3 2007/11/10 16:39:38 sybreon
// Upgraded license to LGPLv3.
// Significant performance optimisations.
//
// Revision 1.2 2007/11/09 20:51:52 sybreon
// Added GET/PUT support through a FSL bus.
//
// Revision 1.1 2007/11/02 03:25:41 sybreon
// New EDK 3.2 compatible design with optional barrel-shifter and multiplier.
// Fixed various minor data hazard bugs.
// Code compatible with -O0/1/2/3/s generated code.
//
module aeMB_regf (/*AUTOARG*/
// Outputs
rREGA, rREGB, rDWBDI, dwb_dat_o, fsl_dat_o,
// Inputs
rOPC, rRA, rRB, rRW, rRD, rMXDST, rPCLNK, rRESULT, rDWBSEL, rBRA,
rDLY, dwb_dat_i, fsl_dat_i, gclk, grst, gena
);
// INTERNAL
output [31:0] rREGA, rREGB;
output [31:0] rDWBDI;
input [5:0] rOPC;
input [4:0] rRA, rRB, rRW, rRD;
input [1:0] rMXDST;
input [31:2] rPCLNK;
input [31:0] rRESULT;
input [3:0] rDWBSEL;
input rBRA, rDLY;
// DATA WISHBONE
output [31:0] dwb_dat_o;
input [31:0] dwb_dat_i;
// FSL WISHBONE
output [31:0] fsl_dat_o;
input [31:0] fsl_dat_i;
// SYSTEM
input gclk, grst, gena;
// --- LOAD SIZER ----------------------------------------------
// Moves the data bytes around depending on the size of the
// operation.
wire [31:0] wDWBDI = dwb_dat_i; // FIXME: Endian
wire [31:0] wFSLDI = fsl_dat_i; // FIXME: Endian
reg [31:0] rDWBDI;
reg [1:0] rSIZ;
always @(/*AUTOSENSE*/rDWBSEL or wDWBDI or wFSLDI) begin
/* 51.2
case (rSIZ)
// FSL
2'o3: rDWBDI <= wFSLDI;
// 32'bit
2'o2: rDWBDI <= wDWBDI;
// 16'bit
2'o1: case (rRESULT[1])
1'b0: rDWBDI <= {16'd0, wDWBDI[31:16]};
1'b1: rDWBDI <= {16'd0, wDWBDI[15:0]};
endcase // case (rRESULT[1])
// 8'bit
2'o0: case (rRESULT[1:0])
2'o0: rDWBDI <= {24'd0, wDWBDI[31:24]};
2'o1: rDWBDI <= {24'd0, wDWBDI[23:16]};
2'o2: rDWBDI <= {24'd0, wDWBDI[15:8]};
2'o3: rDWBDI <= {24'd0, wDWBDI[7:0]};
endcase // case (rRESULT[1:0])
endcase // case (rSIZ)
*/
/* 50.6
case ({rSIZ, rRESULT[1:0]})
// FSL
4'hC, 4'hD, 4'hE, 4'hF: rDWBDI <= wFSLDI;
// 32'bit
4'h8: rDWBDI <= wDWBDI;
// 16'bit
4'h4: rDWBDI <= {16'd0, wDWBDI[31:16]};
4'h6: rDWBDI <= {16'd0, wDWBDI[15:0]};
// 8'bit
4'h0: rDWBDI <= {24'd0, wDWBDI[31:24]};
4'h1: rDWBDI <= {24'd0, wDWBDI[23:16]};
4'h2: rDWBDI <= {24'd0, wDWBDI[15:8]};
4'h3: rDWBDI <= {24'd0, wDWBDI[7:0]};
default: rDWBDI <= 32'hX;
endcase // case (rSIZ)
*/
// 52.0
case (rDWBSEL)
// 8'bit
4'h8: rDWBDI <= {24'd0, wDWBDI[31:24]};
4'h4: rDWBDI <= {24'd0, wDWBDI[23:16]};
4'h2: rDWBDI <= {24'd0, wDWBDI[15:8]};
4'h1: rDWBDI <= {24'd0, wDWBDI[7:0]};
// 16'bit
4'hC: rDWBDI <= {16'd0, wDWBDI[31:16]};
4'h3: rDWBDI <= {16'd0, wDWBDI[15:0]};
// 32'bit
4'hF: rDWBDI <= wDWBDI;
// FSL
4'h0: rDWBDI <= wFSLDI;
// Undefined
default: rDWBDI <= 32'hX;
endcase
end
always @(posedge gclk)
if (grst) begin
/*AUTORESET*/
// Beginning of autoreset for uninitialized flops
rSIZ <= 2'h0;
// End of automatics
end else if (gena) begin
rSIZ <= rOPC[1:0];
end
// --- GENERAL PURPOSE REGISTERS (R0-R31) -----------------------
// LUT RAM implementation is smaller and faster. R0 gets written
// during reset with 0x00 and doesn't change after.
reg [31:0] mARAM[0:31],
mBRAM[0:31],
mDRAM[0:31];
wire [31:0] rREGW = mDRAM[rRW];
wire [31:0] rREGD = mDRAM[rRD];
assign rREGA = mARAM[rRA];
assign rREGB = mBRAM[rRB];
wire fRDWE = |rRW;
reg [31:0] xWDAT;
always @(/*AUTOSENSE*/rDWBDI or rMXDST or rPCLNK or rREGW
or rRESULT)
case (rMXDST)
2'o2: xWDAT <= rDWBDI;
2'o1: xWDAT <= {rPCLNK, 2'o0};
2'o0: xWDAT <= rRESULT;
2'o3: xWDAT <= rREGW; // No change
endcase // case (rMXDST)
always @(posedge gclk)
if (grst | fRDWE) begin
mARAM[rRW] <= xWDAT;
mBRAM[rRW] <= xWDAT;
mDRAM[rRW] <= xWDAT;
end
// --- STORE SIZER ---------------------------------------------
// Replicates the data bytes across depending on the size of the
// operation.
reg [31:0] rDWBDO, xDWBDO;
wire [31:0] xFSL;
wire fFFWD_M = (rRA == rRW) & (rMXDST == 2'o2) & fRDWE;
wire fFFWD_R = (rRA == rRW) & (rMXDST == 2'o0) & fRDWE;
assign fsl_dat_o = rDWBDO;
assign xFSL = (fFFWD_M) ? rDWBDI :
(fFFWD_R) ? rRESULT :
rREGA;
wire [31:0] xDST;
wire fDFWD_M = (rRW == rRD) & (rMXDST == 2'o2) & fRDWE;
wire fDFWD_R = (rRW == rRD) & (rMXDST == 2'o0) & fRDWE;
assign dwb_dat_o = rDWBDO;
assign xDST = (fDFWD_M) ? rDWBDI :
(fDFWD_R) ? rRESULT :
rREGD;
always @(/*AUTOSENSE*/rOPC or xDST or xFSL)
case (rOPC[1:0])
// 8'bit
2'h0: xDWBDO <= {(4){xDST[7:0]}};
// 16'bit
2'h1: xDWBDO <= {(2){xDST[15:0]}};
// 32'bit
2'h2: xDWBDO <= xDST;
// FSL
2'h3: xDWBDO <= xFSL;
//default: xDWBDO <= 32'hX;
endcase // case (rOPC[1:0])
always @(posedge gclk)
if (grst) begin
/*AUTORESET*/
// Beginning of autoreset for uninitialized flops
rDWBDO <= 32'h0;
// End of automatics
end else if (gena) begin
rDWBDO <= #1 xDWBDO;
end
// --- SIMULATION ONLY ------------------------------------------
// Randomise memory to simulate real-world memory
// synopsys translate_off
integer i;
initial begin
for (i=0; i<32; i=i+1) begin
mARAM[i] <= $random;
mBRAM[i] <= $random;
mDRAM[i] <= $random;
end
end
// synopsys translate_on
endmodule // aeMB_regf
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