URL https://opencores.org/ocsvn/6809_6309_compatible_core/6809_6309_compatible_core/trunk

Subversion Repositories 6809_6309_compatible_core

[/] [6809_6309_compatible_core/] [trunk/] [rtl/] [verilog/] [alu16.v] - Blame information for rev 2

Go to most recent revision | Details | Compare with Previous | View Log


/*
 * (c) 2013 Alejandro Paz
 *
 *
 * An alu core
 *
 * ADD, ADC, DAA, SUB, SBC, COM, NEG, CMP, ASR, ASL, ROR, ROL, RCR, RCL
 *
 *
 *
 */
`include "defs.v"
module alu16(
        input wire clk,
        input wire [15:0] a_in,
        input wire [15:0] b_in,
        input wire [7:0] CCR, /* condition code register */
        input wire [4:0] opcode_in, /* ALU opcode */
        input wire sz_in, /* size, low 8 bit, high 16 bit */
        output reg [15:0] q_out, /* ALU result */
        output reg [7:0] CCRo
        );
 
wire c_in, n_in, v_in, z_in, h_in;
assign c_in = CCR[0]; /* carry flag */
assign n_in = CCR[3]; /* neg flag */
assign v_in = CCR[1]; /* overflow flag */
assign z_in = CCR[2]; /* zero flag */
assign h_in = CCR[5]; /* halb-carry flag */
 
 
wire [7:0] add8_r, adc8_r, sub8_r, sbc8_r, com8_r, neg8_r;
wire [7:0] asr8_r, shr8_r, shl8_r, ror8_r, rol8_r, and8_r, or8_r, eor8_r;
wire [15:0] add16_r, adc16_r, sub16_r, sbc16_r, com16_r, neg16_r;
wire [15:0] asr16_r, shr16_r, shl16_r, ror16_r, rol16_r, and16_r, or16_r, eor16_r, mul16_r;
wire [3:0] daa8l_r, daa8h_r;
wire daa_lnm9;
 
wire [7:0] add8_w, adc8_w, com8_w, neg8_w, sub8_w, sbc8_w;
wire [7:0] asr8_w, shr8_w, shl8_w, ror8_w, rol8_w, and8_w, or8_w, eor8_w;
wire [15:0] add16_w, adc16_w, com16_w, neg16_w, sub16_w, sbc16_w;
wire [15:0] asr16_w, shr16_w, shl16_w, ror16_w, rol16_w, and16_w, or16_w, eor16_w, mul16_w;
 
wire cadd8_w, cadc8_w, csub8_w, csbc8_w;
wire cadd16_w, cadc16_w, csub16_w, csbc16_w;
 
wire cadd8_r, cadc8_r, csub8_r, csbc8_r, ccom8_r, cneg8_r;
wire casr8_r, cshr8_r, cshl8_r, cror8_r, crol8_r, cand8_r, cdaa8_r;
wire cadd16_r, cadc16_r, csub16_r, csbc16_r, ccom16_r, cneg16_r;
wire casr16_r, cshr16_r, cshl16_r, cror16_r, crol16_r, cand16_r, cmul16_r;
wire vadd8_r, vadc8_r, vsub8_r, vsbc8_r, vcom8_r, vneg8_r;
wire vasr8_r, vshr8_r, vshl8_r, vror8_r, vrol8_r, vand8_r;
wire vadd16_r, vadc16_r, vsub16_r, vsbc16_r, vcom16_r, vneg16_r;
wire vasr16_r, vshr16_r, vshl16_r, vror16_r, vrol16_r, vand16_r;
 
assign { cadd8_w, add8_w }   = { 1'b0, a_in[7:0] } + { 1'b0, b_in[7:0] };
assign { cadd16_w, add16_w } = { 1'b0, a_in[15:0] } + { 1'b0, b_in[15:0] };
assign { cadc8_w, adc8_w }   = { 1'b0, a_in[7:0] } + { 1'b0, b_in[7:0] } + { 8'h0, c_in };
assign { cadc16_w, adc16_w } = { 1'b0, a_in[15:0] } + { 1'b0, b_in[15:0] } + { 16'h0, c_in };
 
assign { csub8_w, sub8_w }   = { 1'b0, a_in[7:0] } - { 1'b0, b_in[7:0] };
assign { csub16_w, sub16_w } = { 1'b0, a_in[15:0] } - { 1'b0, b_in[15:0] };
assign { csbc8_w, sbc8_w }   = { 1'b0, a_in[7:0] } - { 1'b0, b_in[7:0] } - { 8'h0, c_in };
assign { csbc16_w, sbc16_w } = { 1'b0, a_in[15:0] } - { 1'b0, b_in[15:0] } - { 16'h0, c_in };
 
assign com8_w = ~a_in[7:0];
assign com16_w = ~a_in[15:0];
assign neg8_w = 8'h0 - a_in[7:0];
assign neg16_w = 16'h0 - a_in[15:0];
 
assign asr8_w = { a_in[7], a_in[7:1] };
assign asr16_w = { a_in[15], a_in[15:1] };
 
assign shr8_w = { 1'b0, a_in[7:1] };
assign shr16_w = { 1'b0, a_in[15:1] };
 
assign shl8_w = { a_in[6:0], 1'b0 };
assign shl16_w = { a_in[14:0], 1'b0 };
 
assign ror8_w = { c_in, a_in[7:1] };
assign ror16_w = { c_in, a_in[15:1] };
 
assign rol8_w = { a_in[6:0], c_in };
assign rol16_w = { a_in[14:0], c_in };
 
assign and8_w = a_in[7:0] & b_in[7:0];
assign and16_w = a_in[15:0] & b_in[15:0];
 
assign or8_w = a_in[7:0] | b_in[7:0];
assign or16_w = a_in[15:0] | b_in[15:0];
 
assign eor8_w = a_in[7:0] ^ b_in[7:0];
assign eor16_w = a_in[15:0] ^ b_in[15:0];
assign mul16_w = a_in[7:0] * b_in[7:0];
 
                // ADD, ADC
assign { cadd8_r, add8_r } = { cadd8_w, add8_w };
assign vadd8_r = (a_in[7] & b_in[7] & (~add8_w[7])) | ((~a_in[7]) & (~b_in[7]) & add8_w[7]);
assign { cadd16_r, add16_r } = { cadd16_w, add16_w };
assign vadd16_r = (a_in[15] & b_in[15] & (~add16_w[15])) | ((~a_in[15]) & (~b_in[15]) & add16_w[15]);
assign { cadc8_r, adc8_r } = { cadd8_w, add8_w };
assign vadc8_r = (a_in[7] & b_in[7] & (~add8_w[7])) | ((~a_in[7]) & (~b_in[7]) & adc8_w[7]);
assign { cadc16_r, adc16_r } = { cadd16_w, add16_w };
assign vadc16_r = (a_in[15] & b_in[15] & (~add16_w[15])) | ((~a_in[15]) & (~b_in[15]) & adc16_w[15]);
                // SUB, SUBC
assign { csub8_r, sub8_r } = { csub8_w, sub8_w };
assign vsub8_r = (a_in[7] & (~b_in[7]) & (~sub8_w[7])) | ((~a_in[7]) & b_in[7] & sub8_w[7]);
assign { csub16_r, sub16_r } = { csub16_w, sub16_w };
assign vsub16_r = (a_in[15] & b_in[15] & (~add16_w[15])) | ((~a_in[15]) & b_in[15] & sub16_w[15]);
assign { csbc8_r, sbc8_r } = { csbc8_w, sbc8_w };
assign vsbc8_r = (a_in[7] & b_in[7] | (~sbc8_w[7])) | ((~a_in[7]) & b_in[7] & sbc8_w[7]);
assign { csbc16_r, sbc16_r } = { csbc16_w, sbc16_w };
assign vsbc16_r = (a_in[15] & b_in[15] & (~sbc16_w[15])) | ((~a_in[15]) & b_in[15] & sbc16_w[15]);
                // COM
assign com8_r = com8_w;
assign ccom8_r = com8_w != 8'h0 ? 1'b1:1'b0;
assign vcom8_r = 1'b0;
assign com16_r = com16_w;
assign ccom16_r = com16_w != 16'h0 ? 1'b1:1'b0;
assign vcom16_r = 1'b0;
                // NEG
assign neg8_r = neg8_w;
assign cneg8_r = neg8_w[7] | neg8_w[6] | neg8_w[5] | neg8_w[4] | neg8_w[3] | neg8_w[2] | neg8_w[1] | neg8_w[0];
assign vneg8_r = neg8_w[7] & (~neg8_w[6]) & (~neg8_w[5]) & (~neg8_w[4]) & (~neg8_w[3]) & (~neg8_w[2]) & (~neg8_w[1]) & (~neg8_w[0]);
assign neg16_r = neg16_w;
assign vneg16_r = neg16_w[15] & (~neg16_w[14]) & (~neg16_w[13]) & (~neg16_w[12]) & (~neg16_w[11]) & (~neg16_w[10]) & (~neg16_w[9]) & (~neg16_w[8]) & (~neg16_w[7]) & (~neg16_w[6]) & (~neg16_w[5]) & (~neg16_w[4]) & (~neg16_w[3]) & (~neg16_w[2]) & (~neg16_w[1]) & (~neg16_w[0]);
assign cneg16_r = neg16_w[15] | neg16_w[14] | neg16_w[13] | neg16_w[12] | neg16_w[11] | neg16_w[10] | neg16_w[9] & neg16_w[8] | neg16_w[7] | neg16_w[6] | neg16_w[5] | neg16_w[4] | neg16_w[3] | neg16_w[2] | neg16_w[1] | neg16_w[0];
                // ASR
assign asr8_r = asr8_w;
assign casr8_r = a_in[0];
assign vasr8_r = a_in[0] ^ asr8_w[7];
assign asr16_r = asr16_w;
assign casr16_r = a_in[0];
assign vasr16_r = a_in[0] ^ asr16_w[15];
                // SHR
assign shr8_r = shr8_w;
assign cshr8_r = a_in[0];
assign vshr8_r = a_in[0] ^ shr8_w[7];
assign shr16_r = shr16_w;
assign cshr16_r = a_in[0];
assign vshr16_r = a_in[0] ^ shr16_w[15];
                // SHL
assign shl8_r = shl8_w;
assign cshl8_r = a_in[7];
assign vshl8_r = a_in[7] ^ shl8_w[7];
assign shl16_r = shl16_w;
assign cshl16_r = a_in[15];
assign vshl16_r = a_in[15] ^ shl16_w[15];
                // ROR
assign ror8_r = ror8_w;
assign cror8_r = a_in[0];
assign vror8_r = a_in[0] ^ shr8_w[7];
assign ror16_r = ror16_w;
assign cror16_r = a_in[0];
assign vror16_r = a_in[0] ^ ror16_w[15];
                // ROL
assign rol8_r = shl8_w;
assign crol8_r = a_in[7];
assign vrol8_r = a_in[7] ^ rol8_w[7];
assign rol16_r = rol16_w;
assign crol16_r = a_in[15];
assign vrol16_r = a_in[15] ^ rol16_w[15];
                // AND
assign and8_r = and8_w;
assign cand8_r = c_in;
assign vand8_r = 1'b0;
assign and16_r = and16_w;
assign cand16_r = c_in;
assign vand16_r = 1'b0;
                // OR
assign or8_r = or8_w;
assign or16_r = or16_w;
                // EOR
assign eor8_r = eor8_w;
assign eor16_r = eor16_w;
                // MUL
assign mul16_r = mul16_w;
assign cmul16_r = mul16_w[7];
                // DAA
assign daa_lnm9 = (a_in[3:0] > 9);
assign daa8l_r = (daa_lnm9 | h_in ) ? a_in[3:0] + 4'h6:a_in[3:0];
assign daa8h_r = ((a_in[7:4] > 9) || (c_in == 1'b1) || (a_in[7] & daa_lnm9)) ? a_in[7:4] + 4'h6:a_in[7:4];
assign cdaa8_r = daa8h_r < a_in[7:4];
 
reg c8, h8, n8, v8, z8, c16, n16, v16, z16;
reg [7:0] q8;
reg [15:0] q16;
 
always @(*)
        begin
                q8 = 8'h0;
                q16 = 16'h0;
                c8 = c_in;
                h8 = h_in;
                v8 = v_in;
                c16 = c_in;
                v16 = v_in;
                case (opcode_in)
                        `ADD:
                                begin
                                        q8 = add8_r;
                                        c8 = cadd8_r;
                                        v8 = vadd8_r;
                                        q16 = add16_r;
                                        c16 = cadd16_r;
                                        v16 = vadd16_r;
                                end
                        `ADC:
                                begin
                                        q8 = adc8_r;
                                        c8 = cadc8_r;
                                        v8 = vadc8_r;
                                        q16 = adc16_r;
                                        c16 = cadc16_r;
                                        v16 = vadc16_r;
                                end
                        `CMP, `SUB: // for CMP no register result is written back
                                begin
                                        q8 = sub8_r;
                                        c8 = csub8_r;
                                        v8 = vsub8_r;
                                        q16 = sub16_r;
                                        c16 = csub16_r;
                                        v16 = vsub16_r;
                                end
                        `SBC:
                                begin
                                        q8 = sbc8_r;
                                        c8 = csbc8_r;
                                        v8 = vsbc8_r;
                                        q16 = sbc16_r;
                                        c16 = csbc16_r;
                                        v16 = vsbc16_r;
                                end
                        `COM:
                                begin
                                        q8 = com8_r;
                                        c8 = com8_r;
                                        v8 = vcom8_r;
                                        q16 = com16_r;
                                        c16 = ccom16_r;
                                        v16 = vcom16_r;
                                end
                        `NEG:
                                begin
                                        q8 = neg8_r;
                                        c8 = cneg8_r;
                                        v8 = vneg8_r;
                                        q16 = neg16_r;
                                        c16 = cneg16_r;
                                        v16 = vneg16_r;
                                end
                        `ASR:
                                begin
                                        q8 = asr8_r;
                                        c8 = casr8_r;
                                        v8 = vasr8_r;
                                        q16 = asr16_r;
                                        c16 = casr16_r;
                                        v16 = vasr16_r;
                                end
                        `LSR:
                                begin
                                        q8 = shr8_r;
                                        c8 = cshr8_r;
                                        v8 = vshr8_r;
                                        q16 = shr16_r;
                                        c16 = cshr16_r;
                                        v16 = vshr16_r;
                                end
                        `LSL:
                                begin
                                        q8 = shl8_r;
                                        c8 = cshl8_r;
                                        v8 = vshl8_r;
                                        q16 = shl16_r;
                                        c16 = cshl16_r;
                                        v16 = vshl16_r;
                                end
                        `ROR:
                                begin
                                        q8 = ror8_r;
                                        c8 = cror8_r;
                                        v8 = vror8_r;
                                        q16 = ror16_r;
                                        c16 = cror16_r;
                                        v16 = vror16_r;
                                end
                        `ROL:
                                begin
                                        q8 = rol8_r;
                                        c8 = crol8_r;
                                        v8 = vrol8_r;
                                        q16 = rol16_r;
                                        c16 = crol16_r;
                                        v16 = vrol16_r;
                                end
                        `AND:
                                begin
                                        q8 = and8_r;
                                        c8 = cand8_r;
                                        v8 = vand8_r;
`ifdef HD6309
                                        q16 = and16_r;
                                        c16 = cand16_r;
                                        v16 = vand16_r;
`endif
                                        end
                        `OR:
                                begin
                                        q8 = or8_r;
                                        c8 = cand8_r;
                                        v8 = vand8_r;
`ifdef HD6309
                                        q16 = or16_r;
                                        c16 = cand16_r;
                                        v16 = vand16_r;
`endif
                                end
                        `EOR:
                                begin
                                        q8 = eor8_r;
                                        c8 = cand8_r;
                                        v8 = vand8_r;
`ifdef HD6309
                                        q16 = eor16_r;
                                        c16 = cand16_r;
                                        v16 = vand16_r;
`endif
                                end
                        `DAA:
                                begin // V is undefined, so we don't touch it
                                        q8 = { daa8h_r, daa8l_r };
                                        c8 = cdaa8_r;
                                end
                        `MUL:
                                begin
                                        q16 = mul16_r;
                                        c16 = cmul16_r;
                                end
                        `LD:
                                begin
                                        v8 = 0;
                                        v16 = 0;
                                        q8 = b_in[7:0];
                                        q16 = b_in[15:0];
                                end
                        `ST:
                                begin
                                        q8 = a_in[7:0];
                                        q16 = a_in[15:0];
                                end
                        `T816: // zero extend 8 -> 16
                                begin
                                        q16 = { 8'h0, b_in[7:0] };
                                end
                        `T168L: // 16L -> 8
                                begin
                                        q8 = b_in[7:0];
                                end
                        `T168H: // 16L -> 8
                                begin
                                        q8 = b_in[15:8];
                                end
                        `SEXT: // sign extend
                                begin
                                        q16 = { b_in[7] ? 8'hff:8'h00, b_in[7:0] };
                                end
                endcase
        end
 
reg [7:0] regq8;
reg [15:0] regq16;
reg reg_n_in, reg_z_in;
/* register before second mux */
always @(posedge clk)
        begin
                regq8 <= q8;
                regq16 <= q16;
                reg_n_in <= n_in;
                reg_z_in <= z_in;
        end
 
/* Negative & zero flags */
always @(*)
        begin
                n8 = regq8[7];
                z8 = regq8 == 8'h0;
                n16 = regq16[15];
                z16 = regq16 == 16'h0;
                case (opcode_in)
                        `ADD:
                                begin
                                end
                        `ADC:
                                begin
                                end
                        `CMP, `SUB: // for CMP no register result is written back
                                begin
                                end
                        `SBC:
                                begin
                                end
                        `COM:
                                begin
                                end
                        `NEG:
                                begin
                                end
                        `ASR:
                                begin
                                end
                        `LSR:
                                begin
                                end
                        `LSL:
                                begin
                                end
                        `ROR:
                                begin
                                end
                        `ROL:
                                begin
                                end
                        `AND:
                                begin
                                end
                        `OR:
                                begin
                                end
                        `EOR:
                                begin
                                end
                        `DAA:
                                begin // V is undefined, so we don't touch it
                                end
                        `MUL:
                                begin
                                        n16 = reg_n_in;
                                        z16 = reg_z_in;
                                end
                        `LD:
                                begin
                                end
                        `ST:
                                begin
                                end
                        `T816: // zero extend 8 -> 16
                                begin
                                        n16 = reg_n_in;
                                        z16 = reg_z_in;
                                end
                        `T168L: // 16L -> 8
                                begin
                                        n8 = reg_n_in;
                                        z8 = reg_z_in;
                                end
                        `T168H: // 16L -> 8
                                begin
                                        n8 = reg_n_in;
                                        z8 = reg_z_in;
                                end
                        `SEXT: // sign extend
                                begin
                                        n16 = reg_n_in;
                                        z16 = reg_z_in;
                                end
                endcase
        end
 
 
always @(*)
        begin
                q_out[15:8] = regq16[15:8];
                if (sz_in)
                        q_out[7:0] = regq16[7:0];
                else
                        q_out[7:0] = regq8;
 
                case (opcode_in)
                        `ORCC:
                                CCRo = CCR | b_in[7:0];
                        `ANDCC:
                                CCRo = CCR & b_in[7:0];
                        default:
                                if (sz_in) // 16 bit
                                        CCRo = { CCR[7:4], n16, z16, v16, c16 };
                                else
                                        CCRo = { CCR[7:6], CCR[5], h8, n8, z8, v8, c8 };
                endcase
        end
 
initial
        begin
        end
endmodule
 
 
/*
                            TERMS OF USE: MIT License
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
*/

Browse

Tools

Subversion Repositories 6809_6309_compatible_core

[/] [6809_6309_compatible_core/] [trunk/] [rtl/] [verilog/] [alu16.v] - Blame information for rev 2

Line No.	Rev	Author	Line
1	2	ale500	`/*`
2			`* (c) 2013 Alejandro Paz`
3			`*`
4			`*`
5			`* An alu core`
6			`*`
7			`* ADD, ADC, DAA, SUB, SBC, COM, NEG, CMP, ASR, ASL, ROR, ROL, RCR, RCL`
8			`*`
9			`*`
10			`*`
11			`*/`
12			`include "defs.v"
13			`module alu16(`
14			`input wire clk,`
15			`input wire [15:0] a_in,`
16			`input wire [15:0] b_in,`
17			`input wire [7:0] CCR, /* condition code register */`
18			`input wire [4:0] opcode_in, /* ALU opcode */`
19			`input wire sz_in, /* size, low 8 bit, high 16 bit */`
20			`output reg [15:0] q_out, /* ALU result */`
21			`output reg [7:0] CCRo`
22			`);`
23
24			`wire c_in, n_in, v_in, z_in, h_in;`
25			`assign c_in = CCR[0]; /* carry flag */`
26			`assign n_in = CCR[3]; /* neg flag */`
27			`assign v_in = CCR[1]; /* overflow flag */`
28			`assign z_in = CCR[2]; /* zero flag */`
29			`assign h_in = CCR[5]; /* halb-carry flag */`
30
31
32			`wire [7:0] add8_r, adc8_r, sub8_r, sbc8_r, com8_r, neg8_r;`
33			`wire [7:0] asr8_r, shr8_r, shl8_r, ror8_r, rol8_r, and8_r, or8_r, eor8_r;`
34			`wire [15:0] add16_r, adc16_r, sub16_r, sbc16_r, com16_r, neg16_r;`
35			`wire [15:0] asr16_r, shr16_r, shl16_r, ror16_r, rol16_r, and16_r, or16_r, eor16_r, mul16_r;`
36			`wire [3:0] daa8l_r, daa8h_r;`
37			`wire daa_lnm9;`
38
39			`wire [7:0] add8_w, adc8_w, com8_w, neg8_w, sub8_w, sbc8_w;`
40			`wire [7:0] asr8_w, shr8_w, shl8_w, ror8_w, rol8_w, and8_w, or8_w, eor8_w;`
41			`wire [15:0] add16_w, adc16_w, com16_w, neg16_w, sub16_w, sbc16_w;`
42			`wire [15:0] asr16_w, shr16_w, shl16_w, ror16_w, rol16_w, and16_w, or16_w, eor16_w, mul16_w;`
43
44			`wire cadd8_w, cadc8_w, csub8_w, csbc8_w;`
45			`wire cadd16_w, cadc16_w, csub16_w, csbc16_w;`
46
47			`wire cadd8_r, cadc8_r, csub8_r, csbc8_r, ccom8_r, cneg8_r;`
48			`wire casr8_r, cshr8_r, cshl8_r, cror8_r, crol8_r, cand8_r, cdaa8_r;`
49			`wire cadd16_r, cadc16_r, csub16_r, csbc16_r, ccom16_r, cneg16_r;`
50			`wire casr16_r, cshr16_r, cshl16_r, cror16_r, crol16_r, cand16_r, cmul16_r;`
51			`wire vadd8_r, vadc8_r, vsub8_r, vsbc8_r, vcom8_r, vneg8_r;`
52			`wire vasr8_r, vshr8_r, vshl8_r, vror8_r, vrol8_r, vand8_r;`
53			`wire vadd16_r, vadc16_r, vsub16_r, vsbc16_r, vcom16_r, vneg16_r;`
54			`wire vasr16_r, vshr16_r, vshl16_r, vror16_r, vrol16_r, vand16_r;`
55
56			`assign { cadd8_w, add8_w } = { 1'b0, a_in[7:0] } + { 1'b0, b_in[7:0] };`
57			`assign { cadd16_w, add16_w } = { 1'b0, a_in[15:0] } + { 1'b0, b_in[15:0] };`
58			`assign { cadc8_w, adc8_w } = { 1'b0, a_in[7:0] } + { 1'b0, b_in[7:0] } + { 8'h0, c_in };`
59			`assign { cadc16_w, adc16_w } = { 1'b0, a_in[15:0] } + { 1'b0, b_in[15:0] } + { 16'h0, c_in };`
60
61			`assign { csub8_w, sub8_w } = { 1'b0, a_in[7:0] } - { 1'b0, b_in[7:0] };`
62			`assign { csub16_w, sub16_w } = { 1'b0, a_in[15:0] } - { 1'b0, b_in[15:0] };`
63			`assign { csbc8_w, sbc8_w } = { 1'b0, a_in[7:0] } - { 1'b0, b_in[7:0] } - { 8'h0, c_in };`
64			`assign { csbc16_w, sbc16_w } = { 1'b0, a_in[15:0] } - { 1'b0, b_in[15:0] } - { 16'h0, c_in };`
65
66			`assign com8_w = ~a_in[7:0];`
67			`assign com16_w = ~a_in[15:0];`
68			`assign neg8_w = 8'h0 - a_in[7:0];`
69			`assign neg16_w = 16'h0 - a_in[15:0];`
70
71			`assign asr8_w = { a_in[7], a_in[7:1] };`
72			`assign asr16_w = { a_in[15], a_in[15:1] };`
73
74			`assign shr8_w = { 1'b0, a_in[7:1] };`
75			`assign shr16_w = { 1'b0, a_in[15:1] };`
76
77			`assign shl8_w = { a_in[6:0], 1'b0 };`
78			`assign shl16_w = { a_in[14:0], 1'b0 };`
79
80			`assign ror8_w = { c_in, a_in[7:1] };`
81			`assign ror16_w = { c_in, a_in[15:1] };`
82
83			`assign rol8_w = { a_in[6:0], c_in };`
84			`assign rol16_w = { a_in[14:0], c_in };`
85
86			`assign and8_w = a_in[7:0] & b_in[7:0];`
87			`assign and16_w = a_in[15:0] & b_in[15:0];`
88
89			`assign or8_w = a_in[7:0] \| b_in[7:0];`
90			`assign or16_w = a_in[15:0] \| b_in[15:0];`
91
92			`assign eor8_w = a_in[7:0] ^ b_in[7:0];`
93			`assign eor16_w = a_in[15:0] ^ b_in[15:0];`
94			`assign mul16_w = a_in[7:0] * b_in[7:0];`
95
96			`// ADD, ADC`
97			`assign { cadd8_r, add8_r } = { cadd8_w, add8_w };`
98			`assign vadd8_r = (a_in[7] & b_in[7] & (~add8_w[7])) \| ((~a_in[7]) & (~b_in[7]) & add8_w[7]);`
99			`assign { cadd16_r, add16_r } = { cadd16_w, add16_w };`
100			`assign vadd16_r = (a_in[15] & b_in[15] & (~add16_w[15])) \| ((~a_in[15]) & (~b_in[15]) & add16_w[15]);`
101			`assign { cadc8_r, adc8_r } = { cadd8_w, add8_w };`
102			`assign vadc8_r = (a_in[7] & b_in[7] & (~add8_w[7])) \| ((~a_in[7]) & (~b_in[7]) & adc8_w[7]);`
103			`assign { cadc16_r, adc16_r } = { cadd16_w, add16_w };`
104			`assign vadc16_r = (a_in[15] & b_in[15] & (~add16_w[15])) \| ((~a_in[15]) & (~b_in[15]) & adc16_w[15]);`
105			`// SUB, SUBC`
106			`assign { csub8_r, sub8_r } = { csub8_w, sub8_w };`
107			`assign vsub8_r = (a_in[7] & (~b_in[7]) & (~sub8_w[7])) \| ((~a_in[7]) & b_in[7] & sub8_w[7]);`
108			`assign { csub16_r, sub16_r } = { csub16_w, sub16_w };`
109			`assign vsub16_r = (a_in[15] & b_in[15] & (~add16_w[15])) \| ((~a_in[15]) & b_in[15] & sub16_w[15]);`
110			`assign { csbc8_r, sbc8_r } = { csbc8_w, sbc8_w };`
111			`assign vsbc8_r = (a_in[7] & b_in[7] \| (~sbc8_w[7])) \| ((~a_in[7]) & b_in[7] & sbc8_w[7]);`
112			`assign { csbc16_r, sbc16_r } = { csbc16_w, sbc16_w };`
113			`assign vsbc16_r = (a_in[15] & b_in[15] & (~sbc16_w[15])) \| ((~a_in[15]) & b_in[15] & sbc16_w[15]);`
114			`// COM`
115			`assign com8_r = com8_w;`
116			`assign ccom8_r = com8_w != 8'h0 ? 1'b1:1'b0;`
117			`assign vcom8_r = 1'b0;`
118			`assign com16_r = com16_w;`
119			`assign ccom16_r = com16_w != 16'h0 ? 1'b1:1'b0;`
120			`assign vcom16_r = 1'b0;`
121			`// NEG`
122			`assign neg8_r = neg8_w;`
123			`assign cneg8_r = neg8_w[7] \| neg8_w[6] \| neg8_w[5] \| neg8_w[4] \| neg8_w[3] \| neg8_w[2] \| neg8_w[1] \| neg8_w[0];`
124			`assign vneg8_r = neg8_w[7] & (~neg8_w[6]) & (~neg8_w[5]) & (~neg8_w[4]) & (~neg8_w[3]) & (~neg8_w[2]) & (~neg8_w[1]) & (~neg8_w[0]);`
125			`assign neg16_r = neg16_w;`
126			`assign vneg16_r = neg16_w[15] & (~neg16_w[14]) & (~neg16_w[13]) & (~neg16_w[12]) & (~neg16_w[11]) & (~neg16_w[10]) & (~neg16_w[9]) & (~neg16_w[8]) & (~neg16_w[7]) & (~neg16_w[6]) & (~neg16_w[5]) & (~neg16_w[4]) & (~neg16_w[3]) & (~neg16_w[2]) & (~neg16_w[1]) & (~neg16_w[0]);`
127			`assign cneg16_r = neg16_w[15] \| neg16_w[14] \| neg16_w[13] \| neg16_w[12] \| neg16_w[11] \| neg16_w[10] \| neg16_w[9] & neg16_w[8] \| neg16_w[7] \| neg16_w[6] \| neg16_w[5] \| neg16_w[4] \| neg16_w[3] \| neg16_w[2] \| neg16_w[1] \| neg16_w[0];`
128			`// ASR`
129			`assign asr8_r = asr8_w;`
130			`assign casr8_r = a_in[0];`
131			`assign vasr8_r = a_in[0] ^ asr8_w[7];`
132			`assign asr16_r = asr16_w;`
133			`assign casr16_r = a_in[0];`
134			`assign vasr16_r = a_in[0] ^ asr16_w[15];`
135			`// SHR`
136			`assign shr8_r = shr8_w;`
137			`assign cshr8_r = a_in[0];`
138			`assign vshr8_r = a_in[0] ^ shr8_w[7];`
139			`assign shr16_r = shr16_w;`
140			`assign cshr16_r = a_in[0];`
141			`assign vshr16_r = a_in[0] ^ shr16_w[15];`
142			`// SHL`
143			`assign shl8_r = shl8_w;`
144			`assign cshl8_r = a_in[7];`
145			`assign vshl8_r = a_in[7] ^ shl8_w[7];`
146			`assign shl16_r = shl16_w;`
147			`assign cshl16_r = a_in[15];`
148			`assign vshl16_r = a_in[15] ^ shl16_w[15];`
149			`// ROR`
150			`assign ror8_r = ror8_w;`
151			`assign cror8_r = a_in[0];`
152			`assign vror8_r = a_in[0] ^ shr8_w[7];`
153			`assign ror16_r = ror16_w;`
154			`assign cror16_r = a_in[0];`
155			`assign vror16_r = a_in[0] ^ ror16_w[15];`
156			`// ROL`
157			`assign rol8_r = shl8_w;`
158			`assign crol8_r = a_in[7];`
159			`assign vrol8_r = a_in[7] ^ rol8_w[7];`
160			`assign rol16_r = rol16_w;`
161			`assign crol16_r = a_in[15];`
162			`assign vrol16_r = a_in[15] ^ rol16_w[15];`
163			`// AND`
164			`assign and8_r = and8_w;`
165			`assign cand8_r = c_in;`
166			`assign vand8_r = 1'b0;`
167			`assign and16_r = and16_w;`
168			`assign cand16_r = c_in;`
169			`assign vand16_r = 1'b0;`
170			`// OR`
171			`assign or8_r = or8_w;`
172			`assign or16_r = or16_w;`
173			`// EOR`
174			`assign eor8_r = eor8_w;`
175			`assign eor16_r = eor16_w;`
176			`// MUL`
177			`assign mul16_r = mul16_w;`
178			`assign cmul16_r = mul16_w[7];`
179			`// DAA`
180			`assign daa_lnm9 = (a_in[3:0] > 9);`
181			`assign daa8l_r = (daa_lnm9 \| h_in ) ? a_in[3:0] + 4'h6:a_in[3:0];`
182			`assign daa8h_r = ((a_in[7:4] > 9) \|\| (c_in == 1'b1) \|\| (a_in[7] & daa_lnm9)) ? a_in[7:4] + 4'h6:a_in[7:4];`
183			`assign cdaa8_r = daa8h_r < a_in[7:4];`
184
185			`reg c8, h8, n8, v8, z8, c16, n16, v16, z16;`
186			`reg [7:0] q8;`
187			`reg [15:0] q16;`
188
189			`always @(*)`
190			`begin`
191			`q8 = 8'h0;`
192			`q16 = 16'h0;`
193			`c8 = c_in;`
194			`h8 = h_in;`
195			`v8 = v_in;`
196			`c16 = c_in;`
197			`v16 = v_in;`
198			`case (opcode_in)`
199			`ADD:
200			`begin`
201			`q8 = add8_r;`
202			`c8 = cadd8_r;`
203			`v8 = vadd8_r;`
204			`q16 = add16_r;`
205			`c16 = cadd16_r;`
206			`v16 = vadd16_r;`
207			`end`
208			`ADC:
209			`begin`
210			`q8 = adc8_r;`
211			`c8 = cadc8_r;`
212			`v8 = vadc8_r;`
213			`q16 = adc16_r;`
214			`c16 = cadc16_r;`
215			`v16 = vadc16_r;`
216			`end`
217			`CMP, `SUB: // for CMP no register result is written back
218			`begin`
219			`q8 = sub8_r;`
220			`c8 = csub8_r;`
221			`v8 = vsub8_r;`
222			`q16 = sub16_r;`
223			`c16 = csub16_r;`
224			`v16 = vsub16_r;`
225			`end`
226			`SBC:
227			`begin`
228			`q8 = sbc8_r;`
229			`c8 = csbc8_r;`
230			`v8 = vsbc8_r;`
231			`q16 = sbc16_r;`
232			`c16 = csbc16_r;`
233			`v16 = vsbc16_r;`
234			`end`
235			`COM:
236			`begin`
237			`q8 = com8_r;`
238			`c8 = com8_r;`
239			`v8 = vcom8_r;`
240			`q16 = com16_r;`
241			`c16 = ccom16_r;`
242			`v16 = vcom16_r;`
243			`end`
244			`NEG:
245			`begin`
246			`q8 = neg8_r;`
247			`c8 = cneg8_r;`
248			`v8 = vneg8_r;`
249			`q16 = neg16_r;`
250			`c16 = cneg16_r;`
251			`v16 = vneg16_r;`
252			`end`
253			`ASR:
254			`begin`
255			`q8 = asr8_r;`
256			`c8 = casr8_r;`
257			`v8 = vasr8_r;`
258			`q16 = asr16_r;`
259			`c16 = casr16_r;`
260			`v16 = vasr16_r;`
261			`end`
262			`LSR:
263			`begin`
264			`q8 = shr8_r;`
265			`c8 = cshr8_r;`
266			`v8 = vshr8_r;`
267			`q16 = shr16_r;`
268			`c16 = cshr16_r;`
269			`v16 = vshr16_r;`
270			`end`
271			`LSL:
272			`begin`
273			`q8 = shl8_r;`
274			`c8 = cshl8_r;`
275			`v8 = vshl8_r;`
276			`q16 = shl16_r;`
277			`c16 = cshl16_r;`
278			`v16 = vshl16_r;`
279			`end`
280			`ROR:
281			`begin`
282			`q8 = ror8_r;`
283			`c8 = cror8_r;`
284			`v8 = vror8_r;`
285			`q16 = ror16_r;`
286			`c16 = cror16_r;`
287			`v16 = vror16_r;`
288			`end`
289			`ROL:
290			`begin`
291			`q8 = rol8_r;`
292			`c8 = crol8_r;`
293			`v8 = vrol8_r;`
294			`q16 = rol16_r;`
295			`c16 = crol16_r;`
296			`v16 = vrol16_r;`
297			`end`
298			`AND:
299			`begin`
300			`q8 = and8_r;`
301			`c8 = cand8_r;`
302			`v8 = vand8_r;`
303			`ifdef HD6309
304			`q16 = and16_r;`
305			`c16 = cand16_r;`
306			`v16 = vand16_r;`
307			`endif
308			`end`
309			`OR:
310			`begin`
311			`q8 = or8_r;`
312			`c8 = cand8_r;`
313			`v8 = vand8_r;`
314			`ifdef HD6309
315			`q16 = or16_r;`
316			`c16 = cand16_r;`
317			`v16 = vand16_r;`
318			`endif
319			`end`
320			`EOR:
321			`begin`
322			`q8 = eor8_r;`
323			`c8 = cand8_r;`
324			`v8 = vand8_r;`
325			`ifdef HD6309
326			`q16 = eor16_r;`
327			`c16 = cand16_r;`
328			`v16 = vand16_r;`
329			`endif
330			`end`
331			`DAA:
332			`begin // V is undefined, so we don't touch it`
333			`q8 = { daa8h_r, daa8l_r };`
334			`c8 = cdaa8_r;`
335			`end`
336			`MUL:
337			`begin`
338			`q16 = mul16_r;`
339			`c16 = cmul16_r;`
340			`end`
341			`LD:
342			`begin`
343			`v8 = 0;`
344			`v16 = 0;`
345			`q8 = b_in[7:0];`
346			`q16 = b_in[15:0];`
347			`end`
348			`ST:
349			`begin`
350			`q8 = a_in[7:0];`
351			`q16 = a_in[15:0];`
352			`end`
353			`T816: // zero extend 8 -> 16
354			`begin`
355			`q16 = { 8'h0, b_in[7:0] };`
356			`end`
357			`T168L: // 16L -> 8
358			`begin`
359			`q8 = b_in[7:0];`
360			`end`
361			`T168H: // 16L -> 8
362			`begin`
363			`q8 = b_in[15:8];`
364			`end`
365			`SEXT: // sign extend
366			`begin`
367			`q16 = { b_in[7] ? 8'hff:8'h00, b_in[7:0] };`
368			`end`
369			`endcase`
370			`end`
371
372			`reg [7:0] regq8;`
373			`reg [15:0] regq16;`
374			`reg reg_n_in, reg_z_in;`
375			`/* register before second mux */`
376			`always @(posedge clk)`
377			`begin`
378			`regq8 <= q8;`
379			`regq16 <= q16;`
380			`reg_n_in <= n_in;`
381			`reg_z_in <= z_in;`
382			`end`
383
384			`/* Negative & zero flags */`
385			`always @(*)`
386			`begin`
387			`n8 = regq8[7];`
388			`z8 = regq8 == 8'h0;`
389			`n16 = regq16[15];`
390			`z16 = regq16 == 16'h0;`
391			`case (opcode_in)`
392			`ADD:
393			`begin`
394			`end`
395			`ADC:
396			`begin`
397			`end`
398			`CMP, `SUB: // for CMP no register result is written back
399			`begin`
400			`end`
401			`SBC:
402			`begin`
403			`end`
404			`COM:
405			`begin`
406			`end`
407			`NEG:
408			`begin`
409			`end`
410			`ASR:
411			`begin`
412			`end`
413			`LSR:
414			`begin`
415			`end`
416			`LSL:
417			`begin`
418			`end`
419			`ROR:
420			`begin`
421			`end`
422			`ROL:
423			`begin`
424			`end`
425			`AND:
426			`begin`
427			`end`
428			`OR:
429			`begin`
430			`end`
431			`EOR:
432			`begin`
433			`end`
434			`DAA:
435			`begin // V is undefined, so we don't touch it`
436			`end`
437			`MUL:
438			`begin`
439			`n16 = reg_n_in;`
440			`z16 = reg_z_in;`
441			`end`
442			`LD:
443			`begin`
444			`end`
445			`ST:
446			`begin`
447			`end`
448			`T816: // zero extend 8 -> 16
449			`begin`
450			`n16 = reg_n_in;`
451			`z16 = reg_z_in;`
452			`end`
453			`T168L: // 16L -> 8
454			`begin`
455			`n8 = reg_n_in;`
456			`z8 = reg_z_in;`
457			`end`
458			`T168H: // 16L -> 8
459			`begin`
460			`n8 = reg_n_in;`
461			`z8 = reg_z_in;`
462			`end`
463			`SEXT: // sign extend
464			`begin`
465			`n16 = reg_n_in;`
466			`z16 = reg_z_in;`
467			`end`
468			`endcase`
469			`end`
470
471
472			`always @(*)`
473			`begin`
474			`q_out[15:8] = regq16[15:8];`
475			`if (sz_in)`
476			`q_out[7:0] = regq16[7:0];`
477			`else`
478			`q_out[7:0] = regq8;`
479
480			`case (opcode_in)`
481			`ORCC:
482			`CCRo = CCR \| b_in[7:0];`
483			`ANDCC:
484			`CCRo = CCR & b_in[7:0];`
485			`default:`
486			`if (sz_in) // 16 bit`
487			`CCRo = { CCR[7:4], n16, z16, v16, c16 };`
488			`else`
489			`CCRo = { CCR[7:6], CCR[5], h8, n8, z8, v8, c8 };`
490			`endcase`
491			`end`
492
493			`initial`
494			`begin`
495			`end`
496			`endmodule`
497
498
499			`/*`
500			`TERMS OF USE: MIT License`
501
502			`Permission is hereby granted, free of charge, to any person obtaining a copy`
503			`of this software and associated documentation files (the "Software"), to deal`
504			`in the Software without restriction, including without limitation the rights`
505			`to use, copy, modify, merge, publish, distribute, sublicense, and/or sell`
506			`copies of the Software, and to permit persons to whom the Software is`
507			`furnished to do so, subject to the following conditions:`
508
509			`The above copyright notice and this permission notice shall be included in`
510			`all copies or substantial portions of the Software.`
511
512			`THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR`
513			`IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,`
514			`FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE`
515			`AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER`
516			`LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,ARISING FROM,`
517			`OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN`
518			`THE SOFTWARE.`
519			`*/`