src/sysc/datatypes/fx/scfx_utils.h

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/*****************************************************************************

  The following code is derived, directly or indirectly, from the SystemC
  source code Copyright (c) 1996-2005 by all Contributors.
  All Rights reserved.

  The contents of this file are subject to the restrictions and limitations
  set forth in the SystemC Open Source License Version 2.4 (the "License");
  You may not use this file except in compliance with such restrictions and
  limitations. You may obtain instructions on how to receive a copy of the
  License at http://www.systemc.org/. Software distributed by Contributors
  under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF
  ANY KIND, either express or implied. See the License for the specific
  language governing rights and limitations under the License.

 *****************************************************************************/

/*****************************************************************************

  scfx_utils.h - 

  Original Author: Martin Janssen, Synopsys, Inc.

 *****************************************************************************/

/*****************************************************************************

  MODIFICATION LOG - modifiers, enter your name, affiliation, date and
  changes you are making here.

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#ifndef SCFX_UTILS_H
#define SCFX_UTILS_H


#include "sysc/datatypes/fx/sc_fxdefs.h"
#include "sysc/datatypes/fx/scfx_params.h"
#include "sysc/datatypes/fx/scfx_string.h"


namespace sc_dt
{

// ----------------------------------------------------------------------------
//  Find the most and least significant non-zero bits in a unsigned long
// ----------------------------------------------------------------------------

#define MSB_STATEMENT(n) if( x >> n ) { x >>= n; i += n; }

inline
int
scfx_find_msb( unsigned long x )
{
    int i = 0;
    MSB_STATEMENT( 16 );
    MSB_STATEMENT( 8 );
    MSB_STATEMENT( 4 );
    MSB_STATEMENT( 2 );
    MSB_STATEMENT( 1 );
    return i;
}

#undef MSB_STATEMENT

#define LSB_STATEMENT(n) if( x << n ) { x <<= n; i -= n; }

inline
int
scfx_find_lsb( unsigned long x )
{
    int i = 31;
    LSB_STATEMENT( 16 );
    LSB_STATEMENT( 8 );
    LSB_STATEMENT( 4 );
    LSB_STATEMENT( 2 );
    LSB_STATEMENT( 1 );
    return i;
}

#undef LSB_STATEMENT


// ----------------------------------------------------------------------------
//  Utilities for parsing a character string number
// ----------------------------------------------------------------------------

inline
int
scfx_parse_sign( const char*& s, bool& sign_char )
{
    int sign = 1;

    if( *s == '+' )
    {
        ++ s;
        sign_char = true;
    }
    else if( *s == '-' )
    {
        sign = -1;
        ++ s;
        sign_char = true;
    }
    else
        sign_char = false;

    return sign;
}

inline
sc_numrep
scfx_parse_prefix( const char*& s )
{
    if( s[0] == '0' ) {
        switch( s[1] ) {
        case 'b':
        case 'B':
        {
            if( s[2] == 'u' || s[2] == 'U' && s[3] == 's' || s[3] == 'S' ) {
                s += 4;
                return SC_BIN_US;
            }
            if( s[2] == 's' || s[2] == 'S' && s[3] == 'm' || s[3] == 'M' ) {
                s += 4;
                return SC_BIN_SM;
            }
            s += 2;
            return SC_BIN;
        }
        case 'o':
        case 'O':
        {
            if( s[2] == 'u' || s[2] == 'U' && s[3] == 's' || s[3] == 'S' ) {
                s += 4;
                return SC_OCT_US;
            }
            if( s[2] == 's' || s[2] == 'S' && s[3] == 'm' || s[3] == 'M' ) {
                s += 4;
                return SC_OCT_SM;
            }
            s += 2;
            return SC_OCT;
        }
        case 'x':
        case 'X':
        {
            if( s[2] == 'u' || s[2] == 'U' && s[3] == 's' || s[3] == 'S' ) {
                s += 4;
                return SC_HEX_US;
            }
            if( s[2] == 's' || s[2] == 'S' && s[3] == 'm' || s[3] == 'M' ) {
                s += 4;
                return SC_HEX_SM;
            }
            s += 2;
            return SC_HEX;
        }
        case 'd':
        case 'D':
        {
            s += 2;
            return SC_DEC;
        }
        case 'c':
        case 'C':
        {
            if( s[2] == 's' || s[2] == 'S' && s[3] == 'd' || s[3] == 'D' ) {
                s += 4;
                return SC_CSD;
            }
            break;
        }
        default:
            break;
        }
    }

    return SC_DEC;
}


inline
int
scfx_parse_base( const char*& s )
{
    const char* s1 = s + 1;

    int base = 10;

    if( *s == '0' )
    {
        switch( *s1 )
        {
            case 'b':
            case 'B': base =  2; s += 2; break;
            case 'o':
            case 'O': base =  8; s += 2; break;
            case 'd':
            case 'D': base = 10; s += 2; break;
            case 'x':
            case 'X': base = 16; s += 2; break;
        }
    }

    return base;
}

inline
bool
scfx_is_equal( const char* a, const char* b )
{
    while( *a != 0 && *b != 0 && *a == *b )
    {
        ++ a;
        ++ b;
    }
    return ( *a == 0 && *b == 0 );
}

inline
bool
scfx_is_nan( const char* s )
{
    return scfx_is_equal( s, "NaN" );
}

inline
bool
scfx_is_inf( const char* s )
{
    return ( scfx_is_equal( s, "Inf" ) || scfx_is_equal( s, "Infinity" ) );
}

inline
bool
scfx_exp_start( const char* s )
{
    if( *s == 'e' || *s == 'E' )
    {
        ++ s;
        if( *s == '+' || *s == '-' )
            return true;
    }
    return false;
}

inline
bool
scfx_is_digit( char c, sc_numrep numrep )
{
    bool is_digit;

    switch( numrep )
    {
        case SC_DEC:
        {
            switch( c )
            {
                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                {
                    is_digit = true;
                    break;
                }
                default:
                    is_digit = false;
            }
            break;
        }
        case SC_BIN:
        case SC_BIN_US:
        case SC_BIN_SM:
        {
            switch( c )
            {
                case '0': case '1':
                {
                    is_digit = true;
                    break;
                }
                default:
                    is_digit = false;
            }
            break;
        }
        case SC_OCT:
        case SC_OCT_US:
        case SC_OCT_SM:
        {
            switch( c )
            {
                case '0': case '1': case '2': case '3':
                case '4': case '5': case '6': case '7':
                {
                    is_digit = true;
                    break;
                }
                default:
                    is_digit = false;
            }
            break;
        }
        case SC_HEX:
        case SC_HEX_US:
        case SC_HEX_SM:
        {
            switch( c )
            {
                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
                case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
                {
                    is_digit = true;
                    break;
                }
                default:
                    is_digit = false;
            }
            break;
        }
        case SC_CSD:
        {
            switch( c )
            {
                case '0': case '1': case '-':
                {
                    is_digit = true;
                    break;
                }
                default:
                    is_digit = false;
            }
            break;
        }
        default:
            is_digit = false;
    }

    return is_digit;
}

inline
int
scfx_to_digit( char c, sc_numrep numrep )
{
    int to_digit;
    
    switch( numrep )
    {
        case SC_DEC:
        case SC_BIN:
        case SC_BIN_US:
        case SC_BIN_SM:
        case SC_OCT:
        case SC_OCT_US:
        case SC_OCT_SM:
        {
            to_digit = c - '0';
            break;
        }
        case SC_HEX:
        case SC_HEX_US:
        case SC_HEX_SM:
        {
            switch( c )
            {
                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                    to_digit = c - '0';
                    break;
                case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
                    to_digit = c - 'a' + 10;
                    break;
                case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
                    to_digit = c - 'A' + 10;
                    break;
                default:
                    to_digit = -2;
            }
            break;
        }
        case SC_CSD:
        {
            if( c == '-' )
                to_digit = -1;
            else
                to_digit = c - '0';
        }
        default:
            to_digit = -2;
    };

    return to_digit;
}


// ----------------------------------------------------------------------------
//  Utilities for printing a character string number
// ----------------------------------------------------------------------------

inline
void
scfx_print_nan( scfx_string& s )
{
    s += "NaN";
}

inline
void
scfx_print_inf( scfx_string& s, bool negative )
{
    if( negative )
        s += "-Inf";
    else
        s += "Inf";
}

inline
void
scfx_print_prefix( scfx_string& s, sc_numrep numrep )
{
    switch( numrep )
    {
        case SC_DEC:
            s += "0d";
            break;
        case SC_BIN:
            s += "0b";
            break;
        case SC_BIN_US:
            s += "0bus";
            break;
        case SC_BIN_SM:
            s += "0bsm";
            break;
        case SC_OCT:
            s += "0o";
            break;
        case SC_OCT_US:
            s += "0ous";
            break;
        case SC_OCT_SM:
            s += "0osm";
            break;
        case SC_HEX:
            s += "0x";
            break;
        case SC_HEX_US:
            s += "0xus";
            break;
        case SC_HEX_SM:
            s += "0xsm";
            break;
        case SC_CSD:
            s += "0csd";
            break;
        default:
            s += "unknown";
    }
}

inline
void
scfx_print_exp( scfx_string& s, int exp )
{
    if( exp != 0 )
    {
        s += 'e';
                
        if( exp < 0 )
        {
            exp = - exp;
            s += '-';
        }
        else
            s += '+';

        bool first = true;
        int scale = 1000000000;
        do
        {
            int digit = exp / scale;
            exp = exp % scale;
            if( digit != 0 || ! first )
            {
                s += static_cast<char>( digit + '0' );
                first = false;
            }
            scale /= 10;
        }
        while( scale > 0 );
    }
}


void scfx_tc2csd( scfx_string&, int );
void scfx_csd2tc( scfx_string& );

} // namespace sc_dt


#endif

// Taf!

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