Squashed B200 FPGA Source. Code from Josh Blum, Ian Buckley, and Matt Ettus.

Original-commit: 0df4b801a34697f2058b4a7b95e08d2a0576c9db

lib/vita/float_to_iq.v

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+module float_to_iq
+
+  #(parameter BITS_IN = 32,
+    parameter BITS_OUT = 16
+    )
+
+   (
+
+    input [31:0]   in,
+    output [15:0] out
+    );
+
+   //flags
+
+   wire 		   neg_inf;
+   wire 		   pos_inf;
+   wire 		   denorm;
+   wire tiny_exp;
+   
+
+
+   assign pos_inf = (in[31] == 0 && in[30:23] == 1 && in[22:0] == 0);
+   assign neg_inf = (in[31] == 1 && in[30:23] == 1 && in[22:0] == 0);
+   assign denorm = (in[30:23] == 0);
+   assign tiny_exp = (in[30:23] < 'd111);
+   
+   
+   
+
+
+
+   wire [23:0] 		   implied_bit_fraction;
+   wire [24:0] 		   operation_round;
+   wire [15:0] 		   round_fraction;
+   wire [15:0] 		   shifted_fraction;
+   wire [7:0] 		   shift_val;
+
+   wire [22:0] 		   true_frac;
+   
+
+   
+   
+   assign shift_val = (in[30:23] > 127)? (in[30:23] - 127): (127 - in[30:23]);
+   assign implied_bit_fraction = {1'b1,in[22:0]};
+ 
+   
+   
+   assign operation_round = (implied_bit_fraction + 'h000080);
+   
+
+   //testing for overflow
+   assign round_fraction = (operation_round[24] == 0)?(operation_round[23:8]):(16'h7FFF);
+   //shift the rounded value
+   wire [15:0] shift = round_fraction >> (15 - shift_val);
+   //2's complement the shifted output if the signed bit is 1
+   wire [15:0] final_val = (in[31] == 1)?(~shift + 1'b1):shift;
+   
+   
+
+   assign out = (pos_inf)?{1'b0,15'h7FFF}:(neg_inf)?{1'b1,15'h8000}:(denorm || tiny_exp)? 16'b0: final_val;
+   
+
+
+endmodule
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