| 1 | module Decrementer(in,i,j,out);
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| 2 | input [63:0] in;
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| 3 | input [31:0] i;
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| 4 | input [31:0] j;
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| 5 | output [63:0] out;
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| 6 |
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| 7 | wire [63:0] in1;
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| 8 | wire [63:0] in2;
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| 9 | wire [31:0] out1;
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| 10 | wire [31:0] out2;
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| 11 | //wire [31:0] decrement;
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| 12 |
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| 13 | assign in1[63:32] = in[31:0];
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| 14 | assign in2[63:32] = in[63:32];
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| 15 | assign out[31:0] = out1;
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| 16 | assign out[63:32] = out2;
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| 17 |
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| 18 | assign in1[31:0] = {`32 {1'b1}};
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| 19 | assign in2[31:0] = {`32 {1'b1}};
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| 20 | //assign decrement = {`32 {1'b1}};
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| 21 |
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| 22 | Adder dec1(.in( in1 ), .out( out1 ) );
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| 23 | Adder dec2(.in( in2 ), .out( out2 ) );
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| 24 |
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| 25 | endmodule
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| 26 |
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| 27 | module Adder(in,out);
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| 28 | input [63:0] in;
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| 29 | output [31:0] out;
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| 30 |
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| 31 | wire [31:0] a;
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| 32 | wire [31:0] b;
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| 33 | wire [31:0] sum;
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| 34 |
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| 35 | wire cin;
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| 36 | wire carry;
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| 37 | wire lastcarry;
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| 38 | wire signoverflow_pos;
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| 39 | wire signoverflow_neg;
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| 40 | wire forget;
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| 41 |
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| 42 | assign a = in[31:0];
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| 43 | assign b = in[63:32];
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| 44 | assign cin = 1'b0;
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| 45 |
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| 46 | SingleStage s0( .a( a[0] ), .b( b[0]), .cin( cin ), .s( sum[0]), .cout( ripple0 ) );
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| 47 | SingleStage s1( .a( a[1] ), .b( b[1]), .cin( ripple0 ), .s( sum[1]), .cout( ripple1 ) );
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| 48 | SingleStage s2( .a( a[2] ), .b( b[2]), .cin( ripple1 ), .s( sum[2]), .cout( ripple2 ) );
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| 49 | SingleStage s3( .a( a[3] ), .b( b[3]), .cin( ripple2 ), .s( sum[3]), .cout( ripple3 ) );
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| 50 | SingleStage s4( .a( a[4] ), .b( b[4]), .cin( ripple3 ), .s( sum[4]), .cout( ripple4 ) );
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| 51 | SingleStage s5( .a( a[5] ), .b( b[5]), .cin( ripple4 ), .s( sum[5]), .cout( ripple5 ) );
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| 52 | SingleStage s6( .a( a[6] ), .b( b[6]), .cin( ripple5 ), .s( sum[6]), .cout( ripple6 ) );
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| 53 | SingleStage s7( .a( a[7] ), .b( b[7]), .cin( ripple6 ), .s( sum[7]), .cout( ripple7 ) );
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| 54 | SingleStage s8( .a( a[8] ), .b( b[8]), .cin( ripple7 ), .s( sum[8]), .cout( ripple8 ) );
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| 55 | SingleStage s9( .a( a[9] ), .b( b[9]), .cin( ripple8 ), .s( sum[9]), .cout( ripple9 ) );
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| 56 | SingleStage s10( .a( a[10] ), .b( b[10]), .cin( ripple9 ), .s( sum[10]), .cout( ripple10 ) );
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| 57 | SingleStage s11( .a( a[11] ), .b( b[11]), .cin( ripple10 ), .s( sum[11]), .cout( ripple11 ) );
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| 58 | SingleStage s12( .a( a[12] ), .b( b[12]), .cin( ripple11 ), .s( sum[12]), .cout( ripple12 ) );
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| 59 | SingleStage s13( .a( a[13] ), .b( b[13]), .cin( ripple12 ), .s( sum[13]), .cout( ripple13 ) );
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| 60 | SingleStage s14( .a( a[14] ), .b( b[14]), .cin( ripple13 ), .s( sum[14]), .cout( ripple14 ) );
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| 61 | SingleStage s15( .a( a[15] ), .b( b[15]), .cin( ripple14 ), .s( sum[15]), .cout( ripple15 ) );
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| 62 | SingleStage s16( .a( a[16] ), .b( b[16]), .cin( ripple15 ), .s( sum[16]), .cout( ripple16 ) );
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| 63 | SingleStage s17( .a( a[17] ), .b( b[17]), .cin( ripple16 ), .s( sum[17]), .cout( ripple17 ) );
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| 64 | SingleStage s18( .a( a[18] ), .b( b[18]), .cin( ripple17 ), .s( sum[18]), .cout( ripple18 ) );
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| 65 | SingleStage s19( .a( a[19] ), .b( b[19]), .cin( ripple18 ), .s( sum[19]), .cout( ripple19 ) );
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| 66 | SingleStage s20( .a( a[20] ), .b( b[20]), .cin( ripple19 ), .s( sum[20]), .cout( ripple20 ) );
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| 67 | SingleStage s21( .a( a[21] ), .b( b[21]), .cin( ripple20 ), .s( sum[21]), .cout( ripple21 ) );
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| 68 | SingleStage s22( .a( a[22] ), .b( b[22]), .cin( ripple21 ), .s( sum[22]), .cout( ripple22 ) );
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| 69 | SingleStage s23( .a( a[23] ), .b( b[23]), .cin( ripple22 ), .s( sum[23]), .cout( ripple23 ) );
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| 70 | SingleStage s24( .a( a[24] ), .b( b[24]), .cin( ripple23 ), .s( sum[24]), .cout( ripple24 ) );
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| 71 | SingleStage s25( .a( a[25] ), .b( b[25]), .cin( ripple24 ), .s( sum[25]), .cout( ripple25 ) );
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| 72 | SingleStage s26( .a( a[26] ), .b( b[26]), .cin( ripple25 ), .s( sum[26]), .cout( ripple26 ) );
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| 73 | SingleStage s27( .a( a[27] ), .b( b[27]), .cin( ripple26 ), .s( sum[27]), .cout( ripple27 ) );
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| 74 | SingleStage s28( .a( a[28] ), .b( b[28]), .cin( ripple27 ), .s( sum[28]), .cout( ripple28 ) );
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| 75 | SingleStage s29( .a( a[29] ), .b( b[29]), .cin( ripple28 ), .s( sum[29]), .cout( ripple29 ) );
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| 76 | SingleStage s30( .a( a[30] ), .b( b[30]), .cin( ripple29 ), .s( sum[30]), .cout( ripple30 ) );
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| 77 | SingleStage s31( .a( a[31] ), .b( b[31]), .cin( ripple30 ), .s( sum[31]), .cout( carry ) );
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| 78 |
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| 79 | SingleStage slast( .a( a[30] ), .b( b[30]), .cin( ripple29 ), .s( forget ), .cout( lastcarry ) );
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| 80 |
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| 81 | assign signoverflow_pos = (carry ^ lastcarry) & lastcarry;
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| 82 | assign signoverflow_neg = (carry ^ lastcarry) & carry;
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| 83 |
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| 84 | assign out[0] = (sum[0] | signoverflow_pos) & ~signoverflow_neg;
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| 85 | assign out[1] = (sum[1] | signoverflow_pos) & ~signoverflow_neg;
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| 86 | assign out[2] = (sum[2] | signoverflow_pos) & ~signoverflow_neg;
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| 87 | assign out[3] = (sum[3] | signoverflow_pos) & ~signoverflow_neg;
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| 88 | assign out[4] = (sum[4] | signoverflow_pos) & ~signoverflow_neg;
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| 89 | assign out[5] = (sum[5] | signoverflow_pos) & ~signoverflow_neg;
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| 90 | assign out[6] = (sum[6] | signoverflow_pos) & ~signoverflow_neg;
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| 91 | assign out[7] = (sum[7] | signoverflow_pos) & ~signoverflow_neg;
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| 92 | assign out[8] = (sum[8] | signoverflow_pos) & ~signoverflow_neg;
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| 93 | assign out[9] = (sum[9] | signoverflow_pos) & ~signoverflow_neg;
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| 94 | assign out[10] = (sum[10] | signoverflow_pos) & ~signoverflow_neg;
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| 95 | assign out[11] = (sum[11] | signoverflow_pos) & ~signoverflow_neg;
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| 96 | assign out[12] = (sum[12] | signoverflow_pos) & ~signoverflow_neg;
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| 97 | assign out[13] = (sum[13] | signoverflow_pos) & ~signoverflow_neg;
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| 98 | assign out[14] = (sum[14] | signoverflow_pos) & ~signoverflow_neg;
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| 99 | assign out[15] = (sum[15] | signoverflow_pos) & ~signoverflow_neg;
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| 100 | assign out[16] = (sum[16] | signoverflow_pos) & ~signoverflow_neg;
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| 101 | assign out[17] = (sum[17] | signoverflow_pos) & ~signoverflow_neg;
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| 102 | assign out[18] = (sum[18] | signoverflow_pos) & ~signoverflow_neg;
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| 103 | assign out[19] = (sum[19] | signoverflow_pos) & ~signoverflow_neg;
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| 104 | assign out[20] = (sum[20] | signoverflow_pos) & ~signoverflow_neg;
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| 105 | assign out[21] = (sum[21] | signoverflow_pos) & ~signoverflow_neg;
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| 106 | assign out[22] = (sum[22] | signoverflow_pos) & ~signoverflow_neg;
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| 107 | assign out[23] = (sum[23] | signoverflow_pos) & ~signoverflow_neg;
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| 108 | assign out[24] = (sum[24] | signoverflow_pos) & ~signoverflow_neg;
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| 109 | assign out[25] = (sum[25] | signoverflow_pos) & ~signoverflow_neg;
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| 110 | assign out[26] = (sum[26] | signoverflow_pos) & ~signoverflow_neg;
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| 111 | assign out[27] = (sum[27] | signoverflow_pos) & ~signoverflow_neg;
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| 112 | assign out[28] = (sum[28] | signoverflow_pos) & ~signoverflow_neg;
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| 113 | assign out[29] = (sum[29] | signoverflow_pos) & ~signoverflow_neg;
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| 114 | assign out[30] = (sum[30] | signoverflow_pos) & ~signoverflow_neg;
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| 115 | assign out[31] = (sum[31] & ~signoverflow_pos) | signoverflow_neg;
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| 116 |
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| 117 | endmodule
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| 118 |
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| 119 | module SingleStage(a,b,cin,s,cout);
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| 120 | input a;
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| 121 | input b;
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| 122 | input cin;
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| 123 | output s;
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| 124 | output cout;
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| 125 | assign s = a ^ b ^ cin;
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| 126 | assign cout = (a & b) | (a & cin) | (b & cin);
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| 127 |
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| 128 | endmodule
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| 129 |
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