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/*****************************************************************************
Licensed to Accellera Systems Initiative Inc. (Accellera) under one or
more contributor license agreements. See the NOTICE file distributed
with this work for additional information regarding copyright ownership.
Accellera licenses this file to you under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with the
License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
implied. See the License for the specific language governing
permissions and limitations under the License.
*****************************************************************************/
/*****************************************************************************
floating.cpp -- Floating Point Execution Unit.
Original Author: Martin Wang, Synopsys, Inc.
*****************************************************************************/
/*****************************************************************************
MODIFICATION LOG - modifiers, enter your name, affiliation, date and
changes you are making here.
Name, Affiliation, Date:
Description of Modification:
*****************************************************************************/
#include "systemc.h"
#include "floating.h"
#include "directive.h"
void floating::entry(){
int opcode_tmp = 0;
signed int dout_tmp = 0;
unsigned int dest_tmp = 0;
unsigned int fpua_sign_tmp;
unsigned int fpua_exponent_tmp;
unsigned int fpua_significand_tmp;
unsigned int fpub_sign_tmp;
unsigned int fpub_exponent_tmp;
unsigned int fpub_significand_tmp;
const char * opcode_encode="";
unsigned int fpua_tmp;
unsigned int fpub_tmp;
int exponent_diff_tmp = 0;
unsigned int significant_result = 0;
unsigned int overflow_sign_tmp = 0;
unsigned int result_exp_tmp = 0;
unsigned int result_sign_tmp = 0;
//
// main loop
//
//
// current implementation only worked if both operand have same sign bits
// overflow is ignored.
// initialization of output
wait(3);
while(true) {
do { wait(); } while ( !(in_valid == true) );
dest_tmp = dest.read();
opcode_tmp = opcode.read();
fpua_tmp = floata.read();
fpub_tmp = floatb.read();
fpua_sign_tmp = (fpua_tmp & 0x80000000) >> 31 ;
fpub_sign_tmp = (fpub_tmp & 0x80000000) >> 31 ;
fpua_exponent_tmp = (fpua_tmp & 0x7f800000) >> 23 ;
fpub_exponent_tmp = (fpub_tmp & 0x7f800000) >> 23 ;
fpua_significand_tmp = (fpua_tmp & 0x007fffff) ;
fpub_significand_tmp = (fpub_tmp & 0x007fffff) ;
exponent_diff_tmp = int(fpua_exponent_tmp) - int(fpub_exponent_tmp);
if (PRINT_FPU) {
printf("\t\t\t\t\t\t\t-------------------------------\n");
printf("\t\t\t\t\t\t\tFPU: A s=0x%x, exp=0x%x, mant=0x%x\n",fpua_sign_tmp, fpua_exponent_tmp, fpua_significand_tmp);
printf("\t\t\t\t\t\t\t : B s=0x%x, exp=0x%x, mant=0x%x\n",fpub_sign_tmp, fpub_exponent_tmp, fpub_significand_tmp);
printf("\t\t\t\t\t\t\t : exponent difference = %d\n",exponent_diff_tmp);
printf("\t\t\t\t\t\t\t-------------------------------\n");
}
if (exponent_diff_tmp > 0) {
//printf("shift significant B to Right\n");
fpub_significand_tmp = fpub_significand_tmp >> exponent_diff_tmp ;
fpub_exponent_tmp = fpua_exponent_tmp;
} else {
//printf("shift significant A to Right\n");
fpua_significand_tmp = fpua_significand_tmp >> exponent_diff_tmp ;
fpua_exponent_tmp = fpub_exponent_tmp;
}
wait();
if (PRINT_FPU) {
printf("\t\t\t\t\t\t\t-------------------------------\n");
printf("\t\t\t\t\t\t\tFPU: After Alignment\n");
printf("\t\t\t\t\t\t\tFPU: A s=0x%x, exp=0x%x, mant=0x%x\n",fpua_sign_tmp, fpua_exponent_tmp, fpua_significand_tmp);
printf("\t\t\t\t\t\t\t : B s=0x%x, exp=0x%x, mant=0x%x\n",fpub_sign_tmp, fpub_exponent_tmp, fpub_significand_tmp);
printf("\t\t\t\t\t\t\t-------------------------------\n");
}
// output MUX
switch (opcode_tmp) {
case 0: // Stall
opcode_encode = "STALL";
// dout_tmp = dout_tmp; // keeps its value
wait();
break;
case 3: // add
opcode_encode = "FADD";
significant_result = int(fpua_significand_tmp) + int(fpub_significand_tmp);
wait();
break;
case 4: // sub
opcode_encode = "FSUB";
significant_result = int(fpua_significand_tmp) - int(fpub_significand_tmp);
wait();
break;
case 5: // mul
opcode_encode = "FMUL";
significant_result = int(fpua_significand_tmp) * int(fpub_significand_tmp);
fpub_exponent_tmp *= 2; // exponent is doubled in value
wait();
break;
case 6: // div
opcode_encode = "FDIV";
significant_result = int(fpua_significand_tmp) / int(fpub_significand_tmp);
wait();
break;
default:
printf("\t\t\t\t\t\t\t-------------------------------\n");
printf("\t\t\t\t\t\t\tFPU: Bad Opcode %d.\n",opcode_tmp);
printf("\t\t\t\t\t\t\t-------------------------------\n");
wait();
break;
}
overflow_sign_tmp = (significant_result & 0xff800000) >> 23;
dout_tmp = (significant_result << overflow_sign_tmp) & 0x007fffff ;
result_exp_tmp = fpub_exponent_tmp + overflow_sign_tmp;
dout_tmp = dout_tmp | ((result_exp_tmp << 23) & 0x7f800000) ;
result_sign_tmp = fpua_sign_tmp;
dout_tmp = dout_tmp | ((result_sign_tmp << 31) & 0x80000000) ;
printf("\t\t\t\t\t\t\t-------------------------------\n");
printf("\t\t\t\t\t\t\tFPU: Result Sign=0x%x.\n",result_sign_tmp);
printf("\t\t\t\t\t\t\t : Result Mantissa=0x%x.\n",significant_result);
printf("\t\t\t\t\t\t\t : Result Exponent=0x%x.\n",result_exp_tmp);
printf("\t\t\t\t\t\t\t : Overflow Mantissa=0x%x.\n",overflow_sign_tmp);
cout << "\t\t\t\t\t\t\t : " << opcode_encode;
printf(" FPU Output =0x%x.\n",dout_tmp);
cout <<"\t\t\t\t\t\t\t : at CSIM " << sc_time_stamp() << endl;
printf("\t\t\t\t\t\t\t-------------------------------\n");
fdout.write(dout_tmp);
fout_valid.write(true);
fdestout.write(dest_tmp);
wait();
fout_valid.write(false);
wait();
}
}
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