src/core/fpu/fpu_sign_injection.bsv

   1 /*
   2 Authors     : Vinod.G, Aditya Govardhan
   3 Email       : g.vinod1993@gmail.com
   4 Last Update : 27th November 2017
   5 See LICENSE for more details
   6
   7 Description:
   8 This module performs the sign injection on the floating point value taken from the rs1 register.
   9 The different instructions work as follows
  10 FSGNJ : Operation bit - 000, The final result is same as that of operand1 but has the sign of operand 2's sign.
  11 FSGNJN :  Operation bit - 001, The final result is same as that of operand 1 but has the opposite sign of operand 2's sign
  12 FSGNJX : Operation bit - 010, The final result is same as that of operand 1 but the sign bit is the exclusive-or of operand 1 and operand 2
  13 */
  14
  15 package fpu_sign_injection;
  16
  17 import defined_types::*;
  18 `include "defined_parameters.bsv"
  19
  20 interface Ifc_fpu_sign_injection#(numeric type fpinp, numeric type fpman, numeric type fpexp);
  21         method ActionValue#(Floating_output#(fpinp)) _start(Bit#(fpinp) operand1, Bit#(fpinp) operand2, Bit#(3) operation);
  22 endinterface
  23
  24 `ifdef fpu_hierarchical
  25 interface Ifc_fpu_sign_injection32;
  26         method ActionValue#(Floating_output#(32)) _start(Bit#(32) operand1, Bit#(32) operand2, Bit#(3) operation);
  27 endinterface
  28
  29 interface Ifc_fpu_sign_injection64;
  30         method ActionValue#(Floating_output#(64)) _start(Bit#(64) operand1, Bit#(64) operand2, Bit#(3) operation);
  31 endinterface
  32 `endif
  33
  34
  35 module mkfpu_sign_injection(Ifc_fpu_sign_injection#(fpinp,fpman,fpexp))
  36         provisos (
  37                  Add#(TAdd#(fpexp,fpman),1,fpinp),                      //Defining fpinp to be fpexp + fpman + 1
  38        Add#(fpexp,2,fpexp2)
  39                  );
  40
  41    let fPINP  = valueOf(fpinp);
  42
  43         method ActionValue#(Floating_output#(fpinp)) _start(Bit#(fpinp) operand1, Bit#(fpinp) operand2, Bit#(3) operation);
  44
  45      if(operation == 3'b000)                           //FSGNJ
  46             operand1[fPINP-1] = operand2[fPINP-1];
  47          else if(operation == 3'b001)                      //FSNGNJN
  48             operand1[fPINP-1] = ~operand2[fPINP-1];
  49          else                                              //FSGNJX
  50             operand1[fPINP-1] = operand1[fPINP-1]^operand2[fPINP-1];
  51
  52                 Bit#(5) lv_exception = 0;
  53
  54         return Floating_output {
  55                 final_result : zeroExtend(operand1),
  56                 fflags : lv_exception};
  57         endmethod
  58 endmodule
  59
  60
  61 `ifdef fpu_hierarchical
  62     (*synthesize*)
  63     module mkfpu_sign_injection32(Ifc_fpu_sign_injection32);
  64         Ifc_fpu_sign_injection#(32,23,8) uut <- mkfpu_sign_injection();
  65         method ActionValue#(Floating_output#(32)) _start(Bit#(32) operand1, Bit#(32) operand2, Bit#(3) operation);
  66                let x <- uut._start(operand1,operand2,operation);
  67                return x;
  68         endmethod
  69     endmodule
  70
  71     (*synthesize*)
  72     module mkfpu_sign_injection64(Ifc_fpu_sign_injection64);
  73         Ifc_fpu_sign_injection#(64,52,11) uut <- mkfpu_sign_injection();
  74         method ActionValue#(Floating_output#(64)) _start(Bit#(64) operand1, Bit#(64) operand2, Bit#(3) operation);
  75             let x <- uut._start(operand1,operand2,operation);
  76             return x;
  77         endmethod
  78     endmodule
  79 `endif
  80
  81 // module mkTb_fpu_sign_injection();
  82 // Ifc_fpu_sign_injection#(32,23,8) inst_fpu_sign_injection <- mkfpu_sign_injection();
  83 // Reg#(Bit#(32)) rg_clock <- mkReg(0);
  84 // Reg#(Bit#(32)) rg_operand1<-mkReg('hff800000);
  85 // Reg#(Bit#(32)) rg_operand2<-mkReg('hff800000);
  86
  87 // rule get_input(rg_clock == 0);
  88 // inst_fpu_sign_injection._start(rg_operand1,rg_operand2,'b000);
  89 // rg_clock <= rg_clock + 1;
  90 // endrule
  91
  92 // rule get_output;
  93 // let lv_result = inst_fpu_sign_injection.result_();
  94 // `ifdef verbose $display("Result is: %h",lv_result.final_result); `endif
  95 // `ifdef verbose $display("Sign=%b Exponent=%b Mantissa=%b",lv_result.final_result[31],lv_result.final_result[30:23],lv_result.final_result[22:0]); `endif
  96 // $finish(0);
  97 // endrule
  98
  99
 100
 101 // endmodule
 102 endpackage