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//////////////////////////////////////////////////////////////////////
////                                                              ////
////  OR1200's ALU                                                ////
////                                                              ////
////  This file is part of the OpenRISC 1200 project              ////
////  http://www.opencores.org/cores/or1k/                        ////
////                                                              ////
////  Description                                                 ////
////  ALU                                                         ////
////                                                              ////
////  To Do:                                                      ////
////   - make it smaller and faster                               ////
////                                                              ////
////  Author(s):                                                  ////
////      - Damjan Lampret, lampret@opencores.org                 ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
////                                                              ////
//// Copyright (C) 2000 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: not supported by cvs2svn $
// Revision 1.2  2002/01/14 06:18:22  lampret
// Fixed mem2reg bug in FAST implementation. Updated debug unit to work with new genpc/if.
//
// Revision 1.1  2002/01/03 08:16:15  lampret
// New prefixes for RTL files, prefixed module names. Updated cache controllers and MMUs.
//
// Revision 1.10  2001/11/12 01:45:40  lampret
// Moved flag bit into SR. Changed RF enable from constant enable to dynamic enable for read ports.
//
// Revision 1.9  2001/10/21 17:57:16  lampret
// Removed params from generic_XX.v. Added translate_off/on in sprs.v and id.v. Removed spr_addr from dc.v and ic.v. Fixed CR+LF.
//
// Revision 1.8  2001/10/19 23:28:45  lampret
// Fixed some synthesis warnings. Configured with caches and MMUs.
//
// Revision 1.7  2001/10/14 13:12:09  lampret
// MP3 version.
//
// Revision 1.1.1.1  2001/10/06 10:18:35  igorm
// no message
//
// Revision 1.2  2001/08/09 13:39:33  lampret
// Major clean-up.
//
// Revision 1.1  2001/07/20 00:46:03  lampret
// Development version of RTL. Libraries are missing.
//
//
 
// synopsys translate_off
`include "timescale.v"
// synopsys translate_on
`include "or1200_defines.v"
 
module or1200_alu(
        a, b, mult_mac_result, macrc_op,
        alu_op, shrot_op, comp_op,
        result, flagforw, flag_we
);
 
parameter width = `OR1200_OPERAND_WIDTH;
 
//
// I/O
//
input   [width-1:0]              a;
input   [width-1:0]              b;
input   [width-1:0]              mult_mac_result;
input                           macrc_op;
input   [`OR1200_ALUOP_WIDTH-1:0]        alu_op;
input   [`OR1200_SHROTOP_WIDTH-1:0]      shrot_op;
input   [`OR1200_COMPOP_WIDTH-1:0]       comp_op;
output  [width-1:0]              result;
output                          flagforw;
output                          flag_we;
 
//
// Internal wires and regs
//
reg     [width-1:0]              result;
reg     [width-1:0]              shifted_rotated;
reg                             flagforw;
reg                             flagcomp;
reg                             flag_we;
integer                         d1;
integer                         d2;
wire    [width-1:0]              comp_a;
wire    [width-1:0]              comp_b;
`ifdef OR1200_IMPL_ALU_COMP1
wire                            a_eq_b;
wire                            a_lt_b;
`endif
wire    [width-1:0]              result_sum;
wire    [width-1:0]              result_and;
 
//
// Combinatorial logic
//
assign comp_a = {a[width-1] ^ comp_op[3] , a[width-2:0]};
assign comp_b = {b[width-1] ^ comp_op[3] , b[width-2:0]};
`ifdef OR1200_IMPL_ALU_COMP1
assign a_eq_b = (comp_a == comp_b);
assign a_lt_b = (comp_a < comp_b);
`endif
assign result_sum = a + b;
assign result_and = a & b;
 
//
// Simulation check for bad ALU behavior
//
`ifdef OR1200_WARNINGS
// synopsys translate_off
always @(result) begin
        if (result === 32'bx)
                $display("%t: WARNING: 32'bx detected on ALU result bus. Please check !", $time);
end
// synopsys translate_on
`endif
 
//
// Central part of the ALU
//
always @(alu_op or a or b or result_sum or result_and or macrc_op or shifted_rotated or mult_mac_result) begin
        casex (alu_op)          // synopsys parallel_case full_case
                `OR1200_ALUOP_SHROT : begin
                                result = shifted_rotated;
                end
                `OR1200_ALUOP_ADD : begin
                                result = result_sum;
                end
                `OR1200_ALUOP_SUB : begin
                                result = a - b;
                end
                `OR1200_ALUOP_XOR : begin
                                result = a ^ b;
                end
                `OR1200_ALUOP_OR  : begin
                                result = a | b;
                end
                `OR1200_ALUOP_IMM : begin
                                result = b;
                end
                `OR1200_ALUOP_MOVHI : begin
                                if (macrc_op) begin
                                        result = mult_mac_result;
                                end
                                else begin
                                        result = b << 16;
                                end
                end
                `OR1200_ALUOP_MUL : begin
                                result = mult_mac_result;
`ifdef OR1200_VERBOSE
// synopsys translate_off
                                $display("%t: MUL operation: %h * %h = %h", $time, a, b, mult_mac_result);
// synopsys translate_on
`endif
                end
// synopsys translate_off
`ifdef OR1200_SIM_ALU_DIV
                `OR1200_ALUOP_DIV : begin
                                d1 = a;
                                d2 = b;
                                $display("DIV operation: %d / %d = %d", d1, d2, d1/d2);
                                if (d2)
                                        result = d1 / d2;
                                else
                                        result = 32'h00000000;
                end
`endif
`ifdef OR1200_SIM_ALU_DIVU
                `OR1200_ALUOP_DIVU : begin
                                if (b)
                                        result = a / b;
                                else
                                        result = 32'h00000000;
                end
`endif
// synopsys translate_on
                `OR1200_ALUOP_COMP, `OR1200_ALUOP_AND: begin
                                result = result_and;
                end
        endcase
end
 
//
// Generate flag and flag write enable
//
always @(alu_op or result_sum or result_and or flagcomp) begin
        casex (alu_op)          // synopsys parallel_case full_case
                `OR1200_ALUOP_ADD : begin
                        flagforw = (result_sum == 32'h0000_0000);
                        flag_we = 1'b0;
                end
                `OR1200_ALUOP_AND: begin
                        flagforw = (result_and == 32'h0000_0000);
                        flag_we = 1'b0;
                end
                `OR1200_ALUOP_COMP: begin
                        flagforw = flagcomp;
                        flag_we = 1'b1;
                end
                default: begin
                        flagforw = 1'b0;
                        flag_we = 1'b0;
                end
        endcase
end
 
//
// Shifts and rotation
//
always @(shrot_op or a or b) begin
        case (shrot_op)         // synopsys parallel_case
        `OR1200_SHROTOP_SLL :
                                shifted_rotated = (a << b[4:0]);
                `OR1200_SHROTOP_SRL :
                                shifted_rotated = (a >> b[4:0]);
 
`ifdef OR1200_IMPL_ALU_ROTATE
                `OR1200_SHROTOP_ROR :
                                shifted_rotated = (a << (6'd32-{1'b0, b[4:0]})) | (a >> b[4:0]);
`endif
                default:
                                shifted_rotated = ({32{a[31]}} << (6'd32-{1'b0, b[4:0]})) | a >> b[4:0];
        endcase
end
 
//
// First type of compare implementation
//
`ifdef OR1200_IMPL_ALU_COMP1
always @(comp_op or a_eq_b or a_lt_b) begin
        case(comp_op[2:0])       // synopsys parallel_case full_case
                `OR1200_COP_SFEQ:
                        flagcomp = a_eq_b;
                `OR1200_COP_SFNE:
                        flagcomp = ~a_eq_b;
                `OR1200_COP_SFGT:
                        flagcomp = ~(a_eq_b | a_lt_b);
                `OR1200_COP_SFGE:
                        flagcomp = ~a_lt_b;
                `OR1200_COP_SFLT:
                        flagcomp = a_lt_b;
                `OR1200_COP_SFLE:
                        flagcomp = a_eq_b | a_lt_b;
                default:
                        flagcomp = 1'b0;
        endcase
end
`endif
 
//
// Second type of compare implementation
//
`ifdef OR1200_IMPL_ALU_COMP2
always @(comp_op or comp_a or comp_b) begin
        case(comp_op[2:0])       // synopsys parallel_case full_case
                `OR1200_COP_SFEQ:
                        flagcomp = (comp_a == comp_b);
                `OR1200_COP_SFNE:
                        flagcomp = (comp_a != comp_b);
                `OR1200_COP_SFGT:
                        flagcomp = (comp_a > comp_b);
                `OR1200_COP_SFGE:
                        flagcomp = (comp_a >= comp_b);
                `OR1200_COP_SFLT:
                        flagcomp = (comp_a < comp_b);
                `OR1200_COP_SFLE:
                        flagcomp = (comp_a <= comp_b);
                default:
                        flagcomp = 1'b0;
        endcase
end
`endif
 
endmodule

Line No.	Rev	Author	Line
1	504	lampret	`//////////////////////////////////////////////////////////////////////`
2			`//// ////`
3			`//// OR1200's ALU ////`
4			`//// ////`
5			`//// This file is part of the OpenRISC 1200 project ////`
6			`//// http://www.opencores.org/cores/or1k/ ////`
7			`//// ////`
8			`//// Description ////`
9			`//// ALU ////`
10			`//// ////`
11			`//// To Do: ////`
12			`//// - make it smaller and faster ////`
13			`//// ////`
14			`//// Author(s): ////`
15			`//// - Damjan Lampret, lampret@opencores.org ////`
16			`//// ////`
17			`//////////////////////////////////////////////////////////////////////`
18			`//// ////`
19			`//// Copyright (C) 2000 Authors and OPENCORES.ORG ////`
20			`//// ////`
21			`//// This source file may be used and distributed without ////`
22			`//// restriction provided that this copyright statement is not ////`
23			`//// removed from the file and that any derivative work contains ////`
24			`//// the original copyright notice and the associated disclaimer. ////`
25			`//// ////`
26			`//// This source file is free software; you can redistribute it ////`
27			`//// and/or modify it under the terms of the GNU Lesser General ////`
28			`//// Public License as published by the Free Software Foundation; ////`
29			`//// either version 2.1 of the License, or (at your option) any ////`
30			`//// later version. ////`
31			`//// ////`
32			`//// This source is distributed in the hope that it will be ////`
33			`//// useful, but WITHOUT ANY WARRANTY; without even the implied ////`
34			`//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////`
35			`//// PURPOSE. See the GNU Lesser General Public License for more ////`
36			`//// details. ////`
37			`//// ////`
38			`//// You should have received a copy of the GNU Lesser General ////`
39			`//// Public License along with this source; if not, download it ////`
40			`//// from http://www.opencores.org/lgpl.shtml ////`
41			`//// ////`
42			`//////////////////////////////////////////////////////////////////////`
43			`//`
44			`// CVS Revision History`
45			`//`
46			`// $Log: not supported by cvs2svn $`
47	617	lampret	`// Revision 1.2 2002/01/14 06:18:22 lampret`
48			`// Fixed mem2reg bug in FAST implementation. Updated debug unit to work with new genpc/if.`
49			`//`
50	562	lampret	`// Revision 1.1 2002/01/03 08:16:15 lampret`
51			`// New prefixes for RTL files, prefixed module names. Updated cache controllers and MMUs.`
52			`//`
53	504	lampret	`// Revision 1.10 2001/11/12 01:45:40 lampret`
54			`// Moved flag bit into SR. Changed RF enable from constant enable to dynamic enable for read ports.`
55			`//`
56			`// Revision 1.9 2001/10/21 17:57:16 lampret`
57			`// Removed params from generic_XX.v. Added translate_off/on in sprs.v and id.v. Removed spr_addr from dc.v and ic.v. Fixed CR+LF.`
58			`//`
59			`// Revision 1.8 2001/10/19 23:28:45 lampret`
60			`// Fixed some synthesis warnings. Configured with caches and MMUs.`
61			`//`
62			`// Revision 1.7 2001/10/14 13:12:09 lampret`
63			`// MP3 version.`
64			`//`
65			`// Revision 1.1.1.1 2001/10/06 10:18:35 igorm`
66			`// no message`
67			`//`
68			`// Revision 1.2 2001/08/09 13:39:33 lampret`
69			`// Major clean-up.`
70			`//`
71			`// Revision 1.1 2001/07/20 00:46:03 lampret`
72			`// Development version of RTL. Libraries are missing.`
73			`//`
74			`//`
75
76			`// synopsys translate_off`
77			`include "timescale.v"
78			`// synopsys translate_on`
79			`include "or1200_defines.v"
80
81			`module or1200_alu(`
82			`a, b, mult_mac_result, macrc_op,`
83			`alu_op, shrot_op, comp_op,`
84			`result, flagforw, flag_we`
85			`);`
86
87			parameter width = `OR1200_OPERAND_WIDTH;
88
89			`//`
90			`// I/O`
91			`//`
92			`input [width-1:0] a;`
93			`input [width-1:0] b;`
94			`input [width-1:0] mult_mac_result;`
95			`input macrc_op;`
96			input [`OR1200_ALUOP_WIDTH-1:0] alu_op;
97			input [`OR1200_SHROTOP_WIDTH-1:0] shrot_op;
98			input [`OR1200_COMPOP_WIDTH-1:0] comp_op;
99			`output [width-1:0] result;`
100			`output flagforw;`
101			`output flag_we;`
102
103			`//`
104			`// Internal wires and regs`
105			`//`
106			`reg [width-1:0] result;`
107			`reg [width-1:0] shifted_rotated;`
108			`reg flagforw;`
109	617	lampret	`reg flagcomp;`
110	504	lampret	`reg flag_we;`
111			`integer d1;`
112			`integer d2;`
113			`wire [width-1:0] comp_a;`
114			`wire [width-1:0] comp_b;`
115			`ifdef OR1200_IMPL_ALU_COMP1
116			`wire a_eq_b;`
117			`wire a_lt_b;`
118			`endif
119	617	lampret	`wire [width-1:0] result_sum;`
120			`wire [width-1:0] result_and;`
121	504	lampret
122			`//`
123			`// Combinatorial logic`
124			`//`
125			`assign comp_a = {a[width-1] ^ comp_op[3] , a[width-2:0]};`
126			`assign comp_b = {b[width-1] ^ comp_op[3] , b[width-2:0]};`
127			`ifdef OR1200_IMPL_ALU_COMP1
128			`assign a_eq_b = (comp_a == comp_b);`
129			`assign a_lt_b = (comp_a < comp_b);`
130			`endif
131	617	lampret	`assign result_sum = a + b;`
132			`assign result_and = a & b;`
133	504	lampret
134			`//`
135			`// Simulation check for bad ALU behavior`
136			`//`
137			`ifdef OR1200_WARNINGS
138			`// synopsys translate_off`
139			`always @(result) begin`
140			`if (result === 32'bx)`
141			`$display("%t: WARNING: 32'bx detected on ALU result bus. Please check !", $time);`
142			`end`
143			`// synopsys translate_on`
144			`endif
145
146			`//`
147			`// Central part of the ALU`
148			`//`
149	617	lampret	`always @(alu_op or a or b or result_sum or result_and or macrc_op or shifted_rotated or mult_mac_result) begin`
150	504	lampret	`casex (alu_op) // synopsys parallel_case full_case`
151			`OR1200_ALUOP_SHROT : begin
152			`result = shifted_rotated;`
153			`end`
154			`OR1200_ALUOP_ADD : begin
155	617	lampret	`result = result_sum;`
156	504	lampret	`end`
157			`OR1200_ALUOP_SUB : begin
158			`result = a - b;`
159			`end`
160			`OR1200_ALUOP_XOR : begin
161			`result = a ^ b;`
162			`end`
163			`OR1200_ALUOP_OR : begin
164			`result = a \| b;`
165			`end`
166			`OR1200_ALUOP_IMM : begin
167			`result = b;`
168			`end`
169			`OR1200_ALUOP_MOVHI : begin
170			`if (macrc_op) begin`
171			`result = mult_mac_result;`
172			`end`
173			`else begin`
174			`result = b << 16;`
175			`end`
176			`end`
177			`OR1200_ALUOP_MUL : begin
178			`result = mult_mac_result;`
179			`ifdef OR1200_VERBOSE
180			`// synopsys translate_off`
181			`$display("%t: MUL operation: %h * %h = %h", $time, a, b, mult_mac_result);`
182			`// synopsys translate_on`
183			`endif
184			`end`
185			`// synopsys translate_off`
186			`ifdef OR1200_SIM_ALU_DIV
187			`OR1200_ALUOP_DIV : begin
188			`d1 = a;`
189			`d2 = b;`
190			`$display("DIV operation: %d / %d = %d", d1, d2, d1/d2);`
191			`if (d2)`
192			`result = d1 / d2;`
193			`else`
194			`result = 32'h00000000;`
195			`end`
196			`endif
197			`ifdef OR1200_SIM_ALU_DIVU
198			`OR1200_ALUOP_DIVU : begin
199			`if (b)`
200			`result = a / b;`
201			`else`
202			`result = 32'h00000000;`
203			`end`
204			`endif
205			`// synopsys translate_on`
206	617	lampret	`OR1200_ALUOP_COMP, `OR1200_ALUOP_AND: begin
207			`result = result_and;`
208			`end`
209			`endcase`
210			`end`
211
212			`//`
213			`// Generate flag and flag write enable`
214			`//`
215			`always @(alu_op or result_sum or result_and or flagcomp) begin`
216			`casex (alu_op) // synopsys parallel_case full_case`
217			`OR1200_ALUOP_ADD : begin
218			`flagforw = (result_sum == 32'h0000_0000);`
219			`flag_we = 1'b0;`
220			`end`
221			`OR1200_ALUOP_AND: begin
222			`flagforw = (result_and == 32'h0000_0000);`
223			`flag_we = 1'b0;`
224			`end`
225	504	lampret	`OR1200_ALUOP_COMP: begin
226	617	lampret	`flagforw = flagcomp;`
227			`flag_we = 1'b1;`
228	504	lampret	`end`
229	617	lampret	`default: begin`
230			`flagforw = 1'b0;`
231			`flag_we = 1'b0;`
232	504	lampret	`end`
233			`endcase`
234			`end`
235
236			`//`
237			`// Shifts and rotation`
238			`//`
239			`always @(shrot_op or a or b) begin`
240			`case (shrot_op) // synopsys parallel_case`
241	562	lampret	`OR1200_SHROTOP_SLL :
242	504	lampret	`shifted_rotated = (a << b[4:0]);`
243			`OR1200_SHROTOP_SRL :
244			`shifted_rotated = (a >> b[4:0]);`
245	562	lampret
246	504	lampret	`ifdef OR1200_IMPL_ALU_ROTATE
247			`OR1200_SHROTOP_ROR :
248			`shifted_rotated = (a << (6'd32-{1'b0, b[4:0]})) \| (a >> b[4:0]);`
249			`endif
250			`default:`
251			`shifted_rotated = ({32{a[31]}} << (6'd32-{1'b0, b[4:0]})) \| a >> b[4:0];`
252			`endcase`
253			`end`
254
255			`//`
256			`// First type of compare implementation`
257			`//`
258			`ifdef OR1200_IMPL_ALU_COMP1
259			`always @(comp_op or a_eq_b or a_lt_b) begin`
260	562	lampret	`case(comp_op[2:0]) // synopsys parallel_case full_case`
261	504	lampret	`OR1200_COP_SFEQ:
262	617	lampret	`flagcomp = a_eq_b;`
263	504	lampret	`OR1200_COP_SFNE:
264	617	lampret	`flagcomp = ~a_eq_b;`
265	504	lampret	`OR1200_COP_SFGT:
266	617	lampret	`flagcomp = ~(a_eq_b \| a_lt_b);`
267	504	lampret	`OR1200_COP_SFGE:
268	617	lampret	`flagcomp = ~a_lt_b;`
269	504	lampret	`OR1200_COP_SFLT:
270	617	lampret	`flagcomp = a_lt_b;`
271	504	lampret	`OR1200_COP_SFLE:
272	617	lampret	`flagcomp = a_eq_b \| a_lt_b;`
273	504	lampret	`default:`
274	617	lampret	`flagcomp = 1'b0;`
275	504	lampret	`endcase`
276			`end`
277			`endif
278
279			`//`
280			`// Second type of compare implementation`
281			`//`
282			`ifdef OR1200_IMPL_ALU_COMP2
283			`always @(comp_op or comp_a or comp_b) begin`
284	562	lampret	`case(comp_op[2:0]) // synopsys parallel_case full_case`
285	504	lampret	`OR1200_COP_SFEQ:
286	617	lampret	`flagcomp = (comp_a == comp_b);`
287	504	lampret	`OR1200_COP_SFNE:
288	617	lampret	`flagcomp = (comp_a != comp_b);`
289	504	lampret	`OR1200_COP_SFGT:
290	617	lampret	`flagcomp = (comp_a > comp_b);`
291	504	lampret	`OR1200_COP_SFGE:
292	617	lampret	`flagcomp = (comp_a >= comp_b);`
293	504	lampret	`OR1200_COP_SFLT:
294	617	lampret	`flagcomp = (comp_a < comp_b);`
295	504	lampret	`OR1200_COP_SFLE:
296	617	lampret	`flagcomp = (comp_a <= comp_b);`
297	504	lampret	`default:`
298	617	lampret	`flagcomp = 1'b0;`
299	504	lampret	`endcase`
300			`end`
301			`endif
302
303			`endmodule`

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