Witch of Git - nan-gate/blob - techlib.sv

   1 `define FP3_PINF 3'b010
   2 `define FP3_NINF 3'b110
   3 `define FP3_PNAN 3'b011
   4 `define FP3_ANAN 3'b?11
   5 `define FP3_ANYF 3'b???
   6
   7 // A NaN gate! Computes `Inf - max(x+y, -Inf)`.
   8 // See http://tom7.org/nand/
   9 module nan_fp3(
  10     input      [2:0] A,
  11     input      [2:0] B,
  12     output reg [2:0] Y
  13 );
  14
  15 always begin
  16     casez ({A, B})
  17     {`FP3_ANYF, `FP3_ANAN}, {`FP3_ANAN, `FP3_ANYF}: Y = `FP3_PINF;
  18     {`FP3_PINF, `FP3_NINF}, {`FP3_NINF, `FP3_PINF}: Y = `FP3_PINF;
  19     {`FP3_ANYF, `FP3_PINF}, {`FP3_PINF, `FP3_ANYF}: Y = `FP3_PNAN;
  20     default: Y = `FP3_PINF;
  21     endcase
  22 end
  23 endmodule
  24
  25 // Convert a bit into an fp3
  26 module bit_to_fp3(input A, output [2:0] Y);
  27 assign Y = A ? `FP3_PNAN : `FP3_PINF;
  28 endmodule
  29
  30 // Convert an fp3 into a bit
  31 module fp3_to_bit(input [2:0] A, output reg Y);
  32 always begin
  33     casez (A)
  34     `FP3_ANAN: Y = 1'b1;
  35     default: Y = 1'b0;
  36     endcase
  37 end
  38 endmodule
  39
  40 `define FP4_PINF 4'b0100
  41 `define FP4_NINF 4'b1100
  42 `define FP4_PNAN 4'b0111
  43 `define FP4_1NAN 4'b?101
  44 `define FP4_2NAN 4'b?11?
  45 `define FP4_ANYF 4'b????
  46
  47 module nan_fp4(
  48     input      [3:0] A,
  49     input      [3:0] B,
  50     output reg [3:0] Y
  51 );
  52
  53 always begin
  54     casez ({A, B})
  55     {`FP4_ANYF, `FP4_1NAN}, {`FP4_1NAN, `FP4_ANYF}: Y = `FP4_PINF;
  56     {`FP4_ANYF, `FP4_2NAN}, {`FP4_2NAN, `FP4_ANYF}: Y = `FP4_PINF;
  57     {`FP4_PINF, `FP4_NINF}, {`FP4_NINF, `FP4_PINF}: Y = `FP4_PINF;
  58     {`FP4_ANYF, `FP4_PINF}, {`FP4_PINF, `FP4_ANYF}: Y = `FP4_PNAN;
  59     default: Y = `FP4_PINF;
  60     endcase
  61 end
  62 endmodule
  63
  64 module bit_to_fp4(input A, output [3:0] Y);
  65 assign Y = A ? `FP4_PNAN : `FP4_PINF;
  66 endmodule
  67
  68 module fp4_to_bit(input [3:0] A, output reg Y);
  69 always begin
  70     casez (A)
  71     `FP4_1NAN: Y = 1'b1;
  72     `FP4_2NAN: Y = 1'b1;
  73     default: Y = 1'b0;
  74     endcase
  75 end
  76 endmodule
  77
  78 `define FP5_PINF 5'b01100
  79 `define FP5_NINF 5'b11100
  80 `define FP5_PNAN 5'b01111
  81 `define FP5_1NAN 5'b?1101
  82 `define FP5_2NAN 5'b?111?
  83 `define FP5_ANYF 5'b?????
  84
  85 module nan_fp5(
  86     input      [4:0] A,
  87     input      [4:0] B,
  88     output reg [4:0] Y
  89 );
  90
  91 always begin
  92     casez ({A, B})
  93     {`FP5_ANYF, `FP5_1NAN}, {`FP5_1NAN, `FP5_ANYF}: Y = `FP5_PINF;
  94     {`FP5_ANYF, `FP5_2NAN}, {`FP5_2NAN, `FP5_ANYF}: Y = `FP5_PINF;
  95     {`FP5_PINF, `FP5_NINF}, {`FP5_NINF, `FP5_PINF}: Y = `FP5_PINF;
  96     {`FP5_ANYF, `FP5_PINF}, {`FP5_PINF, `FP5_ANYF}: Y = `FP5_PNAN;
  97     default: Y = `FP5_PINF;
  98     endcase
  99 end
 100 endmodule
 101
 102 module bit_to_fp5(input A, output [4:0] Y);
 103 assign Y = A ? `FP5_PNAN : `FP5_PINF;
 104 endmodule
 105
 106 module fp5_to_bit(input [4:0] A, output reg Y);
 107 always begin
 108     casez (A)
 109     `FP5_1NAN: Y = 1'b1;
 110     `FP5_2NAN: Y = 1'b1;
 111     default: Y = 1'b0;
 112     endcase
 113 end
 114 endmodule