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//////////////////////////////////////////////////////////////////////
////                                                              ////
////  OR1200's Top level multiplier, divider and MAC              ////
////                                                              ////
////  This file is part of the OpenRISC 1200 project              ////
////  http://opencores.org/project,or1k                           ////
////                                                              ////
////  Description                                                 ////
////  Multiplier is 32x32 however multiply instructions only      ////
////  use lower 32 bits of the result. MAC is 32x32=64+64.        ////
////                                                              ////
////  To Do:                                                      ////
////   - make signed division better, w/o negating the operands   ////
////   - implement non-serial divider that is synthesizable       ////
////                                                              ////
////  Author(s):                                                  ////
////      - Damjan Lampret, lampret@opencores.org                 ////
////      - Julius Baxter, julius@opencores.org                   ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
////                                                              ////
//// Copyright (C) 2000, 2010 Authors and OPENCORES.ORG           ////
////                                                              ////
//// This source file may be used and distributed without         ////
//// restriction provided that this copyright statement is not    ////
//// removed from the file and that any derivative work contains  ////
//// the original copyright notice and the associated disclaimer. ////
////                                                              ////
//// This source file 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 2.1 of the License, or (at your option) any   ////
//// later version.                                               ////
////                                                              ////
//// This source 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 this source; if not, download it   ////
//// from http://www.opencores.org/lgpl.shtml                     ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
//
// CVS Revision History
//
// $Log: or1200_mult_mac.v,v $
// Revision 2.0  2010/06/30 11:00:00  ORSoC
// Minor update: 
// Bugs fixed. 
//
 
// synopsys translate_off
`include "timescale.v"
// synopsys translate_on
`include "or1200_defines.v"
 
module or1200_mult_mac(
                       // Clock and reset
                       clk, rst,
 
                       // Multiplier/MAC interface
                       ex_freeze, id_macrc_op, macrc_op, a, b, mac_op, alu_op,
                       result, mult_mac_stall,
 
                       // SPR interface
                       spr_cs, spr_write, spr_addr, spr_dat_i, spr_dat_o
                       );
 
   parameter width = `OR1200_OPERAND_WIDTH;
 
   //
   // I/O
   //
 
   //
   // Clock and reset
   //
   input                                clk;
   input                                rst;
 
   //
   // Multiplier/MAC interface
   //
   input                                ex_freeze;
   input                                id_macrc_op;
   input                                macrc_op;
   input [width-1:0]                     a;
   input [width-1:0]                     b;
   input [`OR1200_MACOP_WIDTH-1:0]       mac_op;
   input [`OR1200_ALUOP_WIDTH-1:0]       alu_op;
   output [width-1:0]                    result;
   output                               mult_mac_stall;
 
   //
   // SPR interface
   //
   input                                spr_cs;
   input                                spr_write;
   input [31:0]                  spr_addr;
   input [31:0]                  spr_dat_i;
   output [31:0]                         spr_dat_o;
 
   //
   // Internal wires and regs
   //
   reg [width-1:0]                       result;
`ifdef OR1200_MULT_IMPLEMENTED
   reg [2*width-1:0]                     mul_prod_r;
   wire                                 alu_op_smul;
   wire                                 alu_op_umul;
   wire                                 alu_op_mul;
 `ifdef OR1200_MULT_SERIAL
   reg [5:0]                             serial_mul_cnt;
   reg                                  mul_free;
 `endif
`else
   wire [2*width-1:0]                    mul_prod_r;
`endif
   wire [2*width-1:0]                    mul_prod;
   wire                                 mul_stall;
 
   wire [`OR1200_MACOP_WIDTH-1:0]        mac_op;
`ifdef OR1200_MAC_IMPLEMENTED
   reg [`OR1200_MACOP_WIDTH-1:0]         mac_op_r1;
   reg [`OR1200_MACOP_WIDTH-1:0]         mac_op_r2;
   reg [`OR1200_MACOP_WIDTH-1:0]         mac_op_r3;
   reg                                  mac_stall_r;
   reg [63:0]                            mac_r;
`else
   wire [`OR1200_MACOP_WIDTH-1:0]        mac_op_r1;
   wire [`OR1200_MACOP_WIDTH-1:0]        mac_op_r2;
   wire [`OR1200_MACOP_WIDTH-1:0]        mac_op_r3;
   wire                                 mac_stall_r;
   wire [63:0]                           mac_r;
`endif
   wire [width-1:0]                      x;
   wire [width-1:0]                      y;
   wire                                 spr_maclo_we;
   wire                                 spr_machi_we;
   wire                                 alu_op_div;
   wire                                 alu_op_udiv;
   wire                                 alu_op_sdiv;
   reg                                  div_free;
   wire                                 div_stall;
`ifdef OR1200_DIV_IMPLEMENTED
 `ifdef OR1200_DIV_SERIAL
   reg [2*width-1:0]                     div_quot_r;
   wire [width-1:0]                      div_tmp;
   reg [5:0]                             div_cntr;
 `else
   reg [width-1:0]                       div_quot_r;
   reg [width-1:0]                       div_quot_generic;
 `endif
`endif
 
   //
   // Combinatorial logic
   //
`ifdef OR1200_MULT_IMPLEMENTED
   assign alu_op_smul = (alu_op == `OR1200_ALUOP_MUL);
   assign alu_op_umul = (alu_op == `OR1200_ALUOP_MULU);
   assign alu_op_mul = alu_op_smul | alu_op_umul;
`endif
`ifdef OR1200_MAC_IMPLEMENTED
   assign spr_maclo_we = spr_cs & spr_write & spr_addr[`OR1200_MAC_ADDR];
   assign spr_machi_we = spr_cs & spr_write & !spr_addr[`OR1200_MAC_ADDR];
   assign spr_dat_o = spr_addr[`OR1200_MAC_ADDR] ? mac_r[31:0] : mac_r[63:32];
`else
   assign spr_maclo_we = 1'b0;
   assign spr_machi_we = 1'b0;
   assign spr_dat_o = 32'h0000_0000;
`endif
`ifdef OR1200_DIV_IMPLEMENTED
   assign alu_op_sdiv = (alu_op == `OR1200_ALUOP_DIV);
   assign alu_op_udiv = (alu_op == `OR1200_ALUOP_DIVU);
   assign alu_op_div = alu_op_sdiv | alu_op_udiv;
`else
   assign alu_op_udiv = 1'b0;
   assign alu_op_sdiv = 1'b0;
   assign alu_op_div = 1'b0;
`endif
 
   assign x = (alu_op_sdiv | alu_op_smul) & a[31] ? ~a + 32'b1 :
              alu_op_div | alu_op_mul | (|mac_op) ? a : 32'd0;
   assign y = (alu_op_sdiv | alu_op_smul) & b[31] ? ~b + 32'b1 :
              alu_op_div | alu_op_mul | (|mac_op) ? b : 32'd0;
 
   //
   // Select result of current ALU operation to be forwarded
   // to next instruction and to WB stage
   //
   always @*
     casez(alu_op)      // synopsys parallel_case
`ifdef OR1200_DIV_IMPLEMENTED
       `OR1200_ALUOP_DIV: begin
          result = a[31] ^ b[31] ? ~div_quot_r[31:0] + 32'd1 : div_quot_r[31:0];
       end
       `OR1200_ALUOP_DIVU: begin
          result = div_quot_r[31:0];
       end
`endif
`ifdef OR1200_MULT_IMPLEMENTED
       `OR1200_ALUOP_MUL: begin
          result = a[31] ^ b[31] ? ~mul_prod_r[31:0] + 32'd1 : mul_prod_r[31:0];
       end
         `OR1200_ALUOP_MULU: begin
          result = mul_prod_r[31:0];
       end
`endif
       default:
`ifdef OR1200_MAC_IMPLEMENTED
 `ifdef OR1200_MAC_SHIFTBY
         result = mac_r[`OR1200_MAC_SHIFTBY+31:`OR1200_MAC_SHIFTBY];
 `else
       result = mac_r[31:0];
 `endif
`else
       result = {width{1'b0}};
`endif
     endcase
 
`ifdef OR1200_MULT_IMPLEMENTED
 `ifdef OR1200_MULT_SERIAL
 
   always @(`OR1200_RST_EVENT rst or posedge clk)
     if (rst == `OR1200_RST_VALUE) begin
        mul_prod_r <=  64'h0000_0000_0000_0000;
        serial_mul_cnt <= 6'd0;
        mul_free <= 1'b1;
 
     end
     else if (|serial_mul_cnt) begin
        serial_mul_cnt <= serial_mul_cnt - 6'd1;
        if (mul_prod_r[0])
          mul_prod_r[(width*2)-1:width-1] <= mul_prod_r[(width*2)-1:width] + x;
        else
          mul_prod_r[(width*2)-1:width-1] <= {1'b0,mul_prod_r[(width*2)-1:
                                                              width]};
        mul_prod_r[width-2:0] <= mul_prod_r[width-1:1];
 
     end
     else if (alu_op_mul && mul_free) begin
        mul_prod_r <= {32'd0, y};
        mul_free <= 0;
        serial_mul_cnt <= 6'b10_0000;
     end
     else if (!ex_freeze | mul_free) begin
        mul_free <= 1'b1;
     end
 
   assign mul_stall = (|serial_mul_cnt);
 
 `else
 
   //
   // Instantiation of the multiplier
   //
  `ifdef OR1200_ASIC_MULTP2_32X32
   or1200_amultp2_32x32 or1200_amultp2_32x32(
                                             .X(x),
                                             .Y(y),
                                             .RST(rst),
                                             .CLK(clk),
                                             .P(mul_prod)
                                             );
  `else // OR1200_ASIC_MULTP2_32X32
   or1200_gmultp2_32x32 or1200_gmultp2_32x32(
                                             .X(x),
                                             .Y(y),
                                             .RST(rst),
                                             .CLK(clk),
                                             .P(mul_prod)
                                             );
  `endif // OR1200_ASIC_MULTP2_32X32   
 
   //
   // Registered output from the multiplier
   //
   always @(`OR1200_RST_EVENT rst or posedge clk)
     if (rst == `OR1200_RST_VALUE) begin
        mul_prod_r <=  64'h0000_0000_0000_0000;
     end
     else begin
        mul_prod_r <=  mul_prod[63:0];
     end
 
   assign mul_stall = 0;
 `endif // !`ifdef OR1200_MULT_SERIAL   
 
`else // OR1200_MULT_IMPLEMENTED
   assign mul_prod = {2*width{1'b0}};
   assign mul_prod_r = {2*width{1'b0}};
   assign mul_stall = 0;
`endif // OR1200_MULT_IMPLEMENTED
 
`ifdef OR1200_MAC_IMPLEMENTED
   // Signal to indicate when we should check for new MAC op
   reg ex_freeze_r;
 
   always @(posedge clk or `OR1200_RST_EVENT rst)
     if (rst == `OR1200_RST_VALUE)
       ex_freeze_r <= 1'b1;
     else
       ex_freeze_r <= ex_freeze;
 
   //
   // Propagation of l.mac opcode, only register it for one cycle
   //
   always @(posedge clk or `OR1200_RST_EVENT rst)
     if (rst == `OR1200_RST_VALUE)
       mac_op_r1 <=  `OR1200_MACOP_WIDTH'b0;
     else
       mac_op_r1 <=  !ex_freeze_r ? mac_op : `OR1200_MACOP_WIDTH'b0;
 
   //
   // Propagation of l.mac opcode
   //
   always @(posedge clk or `OR1200_RST_EVENT rst)
     if (rst == `OR1200_RST_VALUE)
       mac_op_r2 <=  `OR1200_MACOP_WIDTH'b0;
     else
       mac_op_r2 <=  mac_op_r1;
 
   //
   // Propagation of l.mac opcode
   //
   always @(posedge clk or `OR1200_RST_EVENT rst)
     if (rst == `OR1200_RST_VALUE)
       mac_op_r3 <=  `OR1200_MACOP_WIDTH'b0;
     else
       mac_op_r3 <=  mac_op_r2;
 
   //
   // Implementation of MAC
   //
   always @(`OR1200_RST_EVENT rst or posedge clk)
     if (rst == `OR1200_RST_VALUE)
       mac_r <=  64'h0000_0000_0000_0000;
 `ifdef OR1200_MAC_SPR_WE
     else if (spr_maclo_we)
       mac_r[31:0] <=  spr_dat_i;
     else if (spr_machi_we)
       mac_r[63:32] <=  spr_dat_i;
 `endif
     else if (mac_op_r3 == `OR1200_MACOP_MAC)
       mac_r <=  mac_r + mul_prod_r;
     else if (mac_op_r3 == `OR1200_MACOP_MSB)
       mac_r <=  mac_r - mul_prod_r;
     else if (macrc_op && !ex_freeze)
       mac_r <=  64'h0000_0000_0000_0000;
 
   //
   // Stall CPU if l.macrc is in ID and MAC still has to process l.mac 
   // instructions in EX stage (e.g. inside multiplier)
   // This stall signal is also used by the divider.
   //
   always @(`OR1200_RST_EVENT rst or posedge clk)
     if (rst == `OR1200_RST_VALUE)
       mac_stall_r <=  1'b0;
     else
       mac_stall_r <=  (|mac_op | (|mac_op_r1) | (|mac_op_r2)) &
                       (id_macrc_op | mac_stall_r);
`else // OR1200_MAC_IMPLEMENTED
   assign mac_stall_r = 1'b0;
   assign mac_r = {2*width{1'b0}};
   assign mac_op_r1 = `OR1200_MACOP_WIDTH'b0;
   assign mac_op_r2 = `OR1200_MACOP_WIDTH'b0;
   assign mac_op_r3 = `OR1200_MACOP_WIDTH'b0;
`endif // OR1200_MAC_IMPLEMENTED
 
`ifdef OR1200_DIV_IMPLEMENTED
 
   //
   // Serial division
   //
 `ifdef OR1200_DIV_SERIAL
   assign div_tmp = div_quot_r[63:32] - y;
   always @(`OR1200_RST_EVENT rst or posedge clk)
     if (rst == `OR1200_RST_VALUE) begin
        div_quot_r <=  64'h0000_0000_0000_0000;
        div_free <=  1'b1;
        div_cntr <=  6'b00_0000;
     end
     else if (|div_cntr) begin
        if (div_tmp[31])
          div_quot_r <=  {div_quot_r[62:0], 1'b0};
        else
          div_quot_r <=  {div_tmp[30:0], div_quot_r[31:0], 1'b1};
        div_cntr <=  div_cntr - 6'd1;
     end
     else if (alu_op_div && div_free) begin
        div_quot_r <=  {31'b0, x[31:0], 1'b0};
        div_cntr <=  6'b10_0000;
        div_free <=  1'b0;
     end
     else if (div_free | !ex_freeze) begin
        //div_quot_r <=  div_quot[63:0];
        div_free <=  1'b1;
     end
 
   assign div_stall = (|div_cntr);
 
 
 `else // !`ifdef OR1200_DIV_SERIAL
 
   // Full divider
   // TODO: Perhaps provide module that can be technology dependent.
   always @(`OR1200_RST_EVENT rst or posedge clk) begin
      if (rst == `OR1200_RST_VALUE) begin
         div_quot_r <=  32'd0;
         div_quot_generic <= 32'd0;
      end
      else begin
         if (alu_op_udiv & !(|y)) // unsigned divide by 0 - force to MAX
           div_quot_generic[31:0] <= 32'hffff_ffff;
         else if (alu_op_div)
           div_quot_generic[31:0] <= x / y;
      end
 
      // Add any additional statges of pipelining as required here. Ensure
      // ends with div_quot_r.
      // Then add logic to ensure div_stall stays high for as long as the
      // division should take.      
 
      div_quot_r[31:0] <= div_quot_generic;
 
   end
 
   assign div_stall = 0;
 
 `endif
 
`else // !`ifdef OR1200_DIV_IMPLEMENTED
 
   assign div_stall = 0;
 
`endif // !`ifdef OR1200_DIV_IMPLEMENTED
 
 
   //   
   // Stall output
   //
   assign mult_mac_stall = mac_stall_r | div_stall | mul_stall;
 
endmodule

Line No.	Rev	Author	Line
1	350	julius	`//////////////////////////////////////////////////////////////////////`
2			`//// ////`
3			`//// OR1200's Top level multiplier, divider and MAC ////`
4			`//// ////`
5			`//// This file is part of the OpenRISC 1200 project ////`
6			`//// http://opencores.org/project,or1k ////`
7			`//// ////`
8			`//// Description ////`
9			`//// Multiplier is 32x32 however multiply instructions only ////`
10			`//// use lower 32 bits of the result. MAC is 32x32=64+64. ////`
11			`//// ////`
12			`//// To Do: ////`
13			`//// - make signed division better, w/o negating the operands ////`
14	435	julius	`//// - implement non-serial divider that is synthesizable ////`
15	350	julius	`//// ////`
16			`//// Author(s): ////`
17			`//// - Damjan Lampret, lampret@opencores.org ////`
18	435	julius	`//// - Julius Baxter, julius@opencores.org ////`
19	350	julius	`//// ////`
20			`//////////////////////////////////////////////////////////////////////`
21			`//// ////`
22	435	julius	`//// Copyright (C) 2000, 2010 Authors and OPENCORES.ORG ////`
23	350	julius	`//// ////`
24			`//// This source file may be used and distributed without ////`
25			`//// restriction provided that this copyright statement is not ////`
26			`//// removed from the file and that any derivative work contains ////`
27			`//// the original copyright notice and the associated disclaimer. ////`
28			`//// ////`
29			`//// This source file is free software; you can redistribute it ////`
30			`//// and/or modify it under the terms of the GNU Lesser General ////`
31			`//// Public License as published by the Free Software Foundation; ////`
32			`//// either version 2.1 of the License, or (at your option) any ////`
33			`//// later version. ////`
34			`//// ////`
35			`//// This source is distributed in the hope that it will be ////`
36			`//// useful, but WITHOUT ANY WARRANTY; without even the implied ////`
37			`//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////`
38			`//// PURPOSE. See the GNU Lesser General Public License for more ////`
39			`//// details. ////`
40			`//// ////`
41			`//// You should have received a copy of the GNU Lesser General ////`
42			`//// Public License along with this source; if not, download it ////`
43			`//// from http://www.opencores.org/lgpl.shtml ////`
44			`//// ////`
45			`//////////////////////////////////////////////////////////////////////`
46			`//`
47			`// CVS Revision History`
48			`//`
49			`// $Log: or1200_mult_mac.v,v $`
50			`// Revision 2.0 2010/06/30 11:00:00 ORSoC`
51			`// Minor update:`
52			`// Bugs fixed.`
53			`//`
54
55			`// synopsys translate_off`
56			`include "timescale.v"
57			`// synopsys translate_on`
58			`include "or1200_defines.v"
59
60			`module or1200_mult_mac(`
61	435	julius	`// Clock and reset`
62			`clk, rst,`
63	350	julius
64	435	julius	`// Multiplier/MAC interface`
65			`ex_freeze, id_macrc_op, macrc_op, a, b, mac_op, alu_op,`
66			`result, mult_mac_stall,`
67	350	julius
68	435	julius	`// SPR interface`
69			`spr_cs, spr_write, spr_addr, spr_dat_i, spr_dat_o`
70			`);`
71	350	julius
72	435	julius	parameter width = `OR1200_OPERAND_WIDTH;
73	350	julius
74	435	julius	`//`
75			`// I/O`
76			`//`
77	350	julius
78	435	julius	`//`
79			`// Clock and reset`
80			`//`
81			`input clk;`
82			`input rst;`
83	350	julius
84	435	julius	`//`
85			`// Multiplier/MAC interface`
86			`//`
87			`input ex_freeze;`
88			`input id_macrc_op;`
89			`input macrc_op;`
90			`input [width-1:0] a;`
91			`input [width-1:0] b;`
92			input [`OR1200_MACOP_WIDTH-1:0] mac_op;
93			input [`OR1200_ALUOP_WIDTH-1:0] alu_op;
94			`output [width-1:0] result;`
95			`output mult_mac_stall;`
96	350	julius
97	435	julius	`//`
98			`// SPR interface`
99			`//`
100			`input spr_cs;`
101			`input spr_write;`
102			`input [31:0] spr_addr;`
103			`input [31:0] spr_dat_i;`
104			`output [31:0] spr_dat_o;`
105	350	julius
106	435	julius	`//`
107			`// Internal wires and regs`
108			`//`
109			`reg [width-1:0] result;`
110	350	julius	`ifdef OR1200_MULT_IMPLEMENTED
111	435	julius	`reg [2*width-1:0] mul_prod_r;`
112			`wire alu_op_smul;`
113			`wire alu_op_umul;`
114			`wire alu_op_mul;`
115			`ifdef OR1200_MULT_SERIAL
116			`reg [5:0] serial_mul_cnt;`
117			`reg mul_free;`
118			`endif
119	350	julius	`else
120	435	julius	`wire [2*width-1:0] mul_prod_r;`
121	350	julius	`endif
122	435	julius	`wire [2*width-1:0] mul_prod;`
123			`wire mul_stall;`
124
125			wire [`OR1200_MACOP_WIDTH-1:0] mac_op;
126	350	julius	`ifdef OR1200_MAC_IMPLEMENTED
127	435	julius	reg [`OR1200_MACOP_WIDTH-1:0] mac_op_r1;
128			reg [`OR1200_MACOP_WIDTH-1:0] mac_op_r2;
129			reg [`OR1200_MACOP_WIDTH-1:0] mac_op_r3;
130			`reg mac_stall_r;`
131			`reg [63:0] mac_r;`
132	350	julius	`else
133	435	julius	wire [`OR1200_MACOP_WIDTH-1:0] mac_op_r1;
134			wire [`OR1200_MACOP_WIDTH-1:0] mac_op_r2;
135			wire [`OR1200_MACOP_WIDTH-1:0] mac_op_r3;
136			`wire mac_stall_r;`
137			`wire [63:0] mac_r;`
138	350	julius	`endif
139	435	julius	`wire [width-1:0] x;`
140			`wire [width-1:0] y;`
141			`wire spr_maclo_we;`
142			`wire spr_machi_we;`
143			`wire alu_op_div;`
144			`wire alu_op_udiv;`
145			`wire alu_op_sdiv;`
146			`reg div_free;`
147			`wire div_stall;`
148	350	julius	`ifdef OR1200_DIV_IMPLEMENTED
149	435	julius	`ifdef OR1200_DIV_SERIAL
150			`reg [2*width-1:0] div_quot_r;`
151			`wire [width-1:0] div_tmp;`
152			`reg [5:0] div_cntr;`
153			`else
154			`reg [width-1:0] div_quot_r;`
155			`reg [width-1:0] div_quot_generic;`
156			`endif
157	350	julius	`endif
158
159	435	julius	`//`
160			`// Combinatorial logic`
161			`//`
162			`ifdef OR1200_MULT_IMPLEMENTED
163			assign alu_op_smul = (alu_op == `OR1200_ALUOP_MUL);
164			assign alu_op_umul = (alu_op == `OR1200_ALUOP_MULU);
165			`assign alu_op_mul = alu_op_smul \| alu_op_umul;`
166			`endif
167	350	julius	`ifdef OR1200_MAC_IMPLEMENTED
168	435	julius	assign spr_maclo_we = spr_cs & spr_write & spr_addr[`OR1200_MAC_ADDR];
169			assign spr_machi_we = spr_cs & spr_write & !spr_addr[`OR1200_MAC_ADDR];
170			assign spr_dat_o = spr_addr[`OR1200_MAC_ADDR] ? mac_r[31:0] : mac_r[63:32];
171	350	julius	`else
172	435	julius	`assign spr_maclo_we = 1'b0;`
173			`assign spr_machi_we = 1'b0;`
174			`assign spr_dat_o = 32'h0000_0000;`
175	350	julius	`endif
176			`ifdef OR1200_DIV_IMPLEMENTED
177	435	julius	assign alu_op_sdiv = (alu_op == `OR1200_ALUOP_DIV);
178			assign alu_op_udiv = (alu_op == `OR1200_ALUOP_DIVU);
179			`assign alu_op_div = alu_op_sdiv \| alu_op_udiv;`
180	350	julius	`else
181	435	julius	`assign alu_op_udiv = 1'b0;`
182			`assign alu_op_sdiv = 1'b0;`
183			`assign alu_op_div = 1'b0;`
184	350	julius	`endif
185
186	435	julius	`assign x = (alu_op_sdiv \| alu_op_smul) & a[31] ? ~a + 32'b1 :`
187			`alu_op_div \| alu_op_mul \| (\|mac_op) ? a : 32'd0;`
188			`assign y = (alu_op_sdiv \| alu_op_smul) & b[31] ? ~b + 32'b1 :`
189			`alu_op_div \| alu_op_mul \| (\|mac_op) ? b : 32'd0;`
190	350	julius
191	435	julius	`//`
192			`// Select result of current ALU operation to be forwarded`
193			`// to next instruction and to WB stage`
194			`//`
195			`always @*`
196			`casez(alu_op) // synopsys parallel_case`
197			`ifdef OR1200_DIV_IMPLEMENTED
198			`OR1200_ALUOP_DIV: begin
199			`result = a[31] ^ b[31] ? ~div_quot_r[31:0] + 32'd1 : div_quot_r[31:0];`
200			`end`
201			`OR1200_ALUOP_DIVU: begin
202			`result = div_quot_r[31:0];`
203			`end`
204			`endif
205			`ifdef OR1200_MULT_IMPLEMENTED
206			`OR1200_ALUOP_MUL: begin
207			`result = a[31] ^ b[31] ? ~mul_prod_r[31:0] + 32'd1 : mul_prod_r[31:0];`
208			`end`
209			`OR1200_ALUOP_MULU: begin
210			`result = mul_prod_r[31:0];`
211			`end`
212			`endif
213			`default:`
214			`ifdef OR1200_MAC_IMPLEMENTED
215	350	julius	`ifdef OR1200_MAC_SHIFTBY
216	435	julius	result = mac_r[`OR1200_MAC_SHIFTBY+31:`OR1200_MAC_SHIFTBY];
217	350	julius	`else
218	435	julius	`result = mac_r[31:0];`
219	350	julius	`endif
220	435	julius	`else
221			`result = {width{1'b0}};`
222			`endif
223			`endcase`
224
225			`ifdef OR1200_MULT_IMPLEMENTED
226			`ifdef OR1200_MULT_SERIAL
227
228			always @(`OR1200_RST_EVENT rst or posedge clk)
229			if (rst == `OR1200_RST_VALUE) begin
230			`mul_prod_r <= 64'h0000_0000_0000_0000;`
231			`serial_mul_cnt <= 6'd0;`
232			`mul_free <= 1'b1;`
233
234			`end`
235			`else if (\|serial_mul_cnt) begin`
236			`serial_mul_cnt <= serial_mul_cnt - 6'd1;`
237			`if (mul_prod_r[0])`
238			`mul_prod_r[(width2)-1:width-1] <= mul_prod_r[(width2)-1:width] + x;`
239			`else`
240			`mul_prod_r[(width2)-1:width-1] <= {1'b0,mul_prod_r[(width2)-1:`
241			`width]};`
242			`mul_prod_r[width-2:0] <= mul_prod_r[width-1:1];`
243
244			`end`
245			`else if (alu_op_mul && mul_free) begin`
246			`mul_prod_r <= {32'd0, y};`
247			`mul_free <= 0;`
248			`serial_mul_cnt <= 6'b10_0000;`
249			`end`
250			`else if (!ex_freeze \| mul_free) begin`
251			`mul_free <= 1'b1;`
252			`end`
253
254			`assign mul_stall = (\|serial_mul_cnt);`
255	350	julius
256	435	julius	`else
257
258	350	julius	`//`
259			`// Instantiation of the multiplier`
260			`//`
261	435	julius	`ifdef OR1200_ASIC_MULTP2_32X32
262			`or1200_amultp2_32x32 or1200_amultp2_32x32(`
263			`.X(x),`
264			`.Y(y),`
265			`.RST(rst),`
266			`.CLK(clk),`
267			`.P(mul_prod)`
268			`);`
269			`else // OR1200_ASIC_MULTP2_32X32
270			`or1200_gmultp2_32x32 or1200_gmultp2_32x32(`
271			`.X(x),`
272			`.Y(y),`
273			`.RST(rst),`
274			`.CLK(clk),`
275			`.P(mul_prod)`
276			`);`
277			`endif // OR1200_ASIC_MULTP2_32X32
278
279			`//`
280			`// Registered output from the multiplier`
281			`//`
282			always @(`OR1200_RST_EVENT rst or posedge clk)
283			if (rst == `OR1200_RST_VALUE) begin
284			`mul_prod_r <= 64'h0000_0000_0000_0000;`
285			`end`
286			`else begin`
287			`mul_prod_r <= mul_prod[63:0];`
288			`end`
289	350	julius
290	435	julius	`assign mul_stall = 0;`
291			`endif // !`ifdef OR1200_MULT_SERIAL
292
293	350	julius	`else // OR1200_MULT_IMPLEMENTED
294	435	julius	`assign mul_prod = {2*width{1'b0}};`
295			`assign mul_prod_r = {2*width{1'b0}};`
296			`assign mul_stall = 0;`
297	350	julius	`endif // OR1200_MULT_IMPLEMENTED
298
299			`ifdef OR1200_MAC_IMPLEMENTED
300	435	julius	`// Signal to indicate when we should check for new MAC op`
301			`reg ex_freeze_r;`
302	356	julius
303	435	julius	always @(posedge clk or `OR1200_RST_EVENT rst)
304			if (rst == `OR1200_RST_VALUE)
305			`ex_freeze_r <= 1'b1;`
306			`else`
307			`ex_freeze_r <= ex_freeze;`
308	356	julius
309	435	julius	`//`
310			`// Propagation of l.mac opcode, only register it for one cycle`
311			`//`
312			always @(posedge clk or `OR1200_RST_EVENT rst)
313			if (rst == `OR1200_RST_VALUE)
314			mac_op_r1 <= `OR1200_MACOP_WIDTH'b0;
315			`else`
316			mac_op_r1 <= !ex_freeze_r ? mac_op : `OR1200_MACOP_WIDTH'b0;
317	350	julius
318	435	julius	`//`
319			`// Propagation of l.mac opcode`
320			`//`
321			always @(posedge clk or `OR1200_RST_EVENT rst)
322			if (rst == `OR1200_RST_VALUE)
323			mac_op_r2 <= `OR1200_MACOP_WIDTH'b0;
324			`else`
325			`mac_op_r2 <= mac_op_r1;`
326	350	julius
327	435	julius	`//`
328			`// Propagation of l.mac opcode`
329			`//`
330			always @(posedge clk or `OR1200_RST_EVENT rst)
331			if (rst == `OR1200_RST_VALUE)
332			mac_op_r3 <= `OR1200_MACOP_WIDTH'b0;
333			`else`
334			`mac_op_r3 <= mac_op_r2;`
335	350	julius
336	435	julius	`//`
337			`// Implementation of MAC`
338			`//`
339			always @(`OR1200_RST_EVENT rst or posedge clk)
340			if (rst == `OR1200_RST_VALUE)
341			`mac_r <= 64'h0000_0000_0000_0000;`
342			`ifdef OR1200_MAC_SPR_WE
343			`else if (spr_maclo_we)`
344			`mac_r[31:0] <= spr_dat_i;`
345			`else if (spr_machi_we)`
346			`mac_r[63:32] <= spr_dat_i;`
347			`endif
348			else if (mac_op_r3 == `OR1200_MACOP_MAC)
349			`mac_r <= mac_r + mul_prod_r;`
350			else if (mac_op_r3 == `OR1200_MACOP_MSB)
351			`mac_r <= mac_r - mul_prod_r;`
352			`else if (macrc_op && !ex_freeze)`
353			`mac_r <= 64'h0000_0000_0000_0000;`
354	350	julius
355	435	julius	`//`
356			`// Stall CPU if l.macrc is in ID and MAC still has to process l.mac`
357			`// instructions in EX stage (e.g. inside multiplier)`
358			`// This stall signal is also used by the divider.`
359			`//`
360			always @(`OR1200_RST_EVENT rst or posedge clk)
361			if (rst == `OR1200_RST_VALUE)
362			`mac_stall_r <= 1'b0;`
363			`else`
364			`mac_stall_r <= (\|mac_op \| (\|mac_op_r1) \| (\|mac_op_r2)) &`
365			`(id_macrc_op \| mac_stall_r);`
366	350	julius	`else // OR1200_MAC_IMPLEMENTED
367	435	julius	`assign mac_stall_r = 1'b0;`
368			`assign mac_r = {2*width{1'b0}};`
369			assign mac_op_r1 = `OR1200_MACOP_WIDTH'b0;
370			assign mac_op_r2 = `OR1200_MACOP_WIDTH'b0;
371			assign mac_op_r3 = `OR1200_MACOP_WIDTH'b0;
372	350	julius	`endif // OR1200_MAC_IMPLEMENTED
373
374	435	julius	`ifdef OR1200_DIV_IMPLEMENTED
375
376			`//`
377			`// Serial division`
378			`//`
379			`ifdef OR1200_DIV_SERIAL
380			`assign div_tmp = div_quot_r[63:32] - y;`
381			always @(`OR1200_RST_EVENT rst or posedge clk)
382			if (rst == `OR1200_RST_VALUE) begin
383			`div_quot_r <= 64'h0000_0000_0000_0000;`
384			`div_free <= 1'b1;`
385			`div_cntr <= 6'b00_0000;`
386			`end`
387			`else if (\|div_cntr) begin`
388			`if (div_tmp[31])`
389			`div_quot_r <= {div_quot_r[62:0], 1'b0};`
390			`else`
391			`div_quot_r <= {div_tmp[30:0], div_quot_r[31:0], 1'b1};`
392			`div_cntr <= div_cntr - 6'd1;`
393			`end`
394			`else if (alu_op_div && div_free) begin`
395			`div_quot_r <= {31'b0, x[31:0], 1'b0};`
396			`div_cntr <= 6'b10_0000;`
397			`div_free <= 1'b0;`
398			`end`
399			`else if (div_free \| !ex_freeze) begin`
400			`//div_quot_r <= div_quot[63:0];`
401			`div_free <= 1'b1;`
402			`end`
403
404			`assign div_stall = (\|div_cntr);`
405
406
407			`else // !`ifdef OR1200_DIV_SERIAL
408
409			`// Full divider`
410			`// TODO: Perhaps provide module that can be technology dependent.`
411			always @(`OR1200_RST_EVENT rst or posedge clk) begin
412			if (rst == `OR1200_RST_VALUE) begin
413			`div_quot_r <= 32'd0;`
414			`div_quot_generic <= 32'd0;`
415			`end`
416			`else begin`
417			`if (alu_op_udiv & !(\|y)) // unsigned divide by 0 - force to MAX`
418			`div_quot_generic[31:0] <= 32'hffff_ffff;`
419			`else if (alu_op_div)`
420			`div_quot_generic[31:0] <= x / y;`
421			`end`
422
423			`// Add any additional statges of pipelining as required here. Ensure`
424			`// ends with div_quot_r.`
425			`// Then add logic to ensure div_stall stays high for as long as the`
426			`// division should take.`
427
428			`div_quot_r[31:0] <= div_quot_generic;`
429
430			`end`
431
432			`assign div_stall = 0;`
433
434			`endif
435
436			`else // !`ifdef OR1200_DIV_IMPLEMENTED
437
438			`assign div_stall = 0;`
439
440			`endif // !`ifdef OR1200_DIV_IMPLEMENTED
441
442
443			`//`
444			`// Stall output`
445			`//`
446			`assign mult_mac_stall = mac_stall_r \| div_stall \| mul_stall;`
447
448	350	julius	`endmodule`

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