dsp.cc

来自「M5,一个功能强大的多处理器系统模拟器.很多针对处理器架构,性能的研究都使用它作」· CC 代码 · 共 1,233 行 · 第 1/3 页

/*
 * Copyright (c) 2007 MIPS Technologies, Inc.  All Rights Reserved
 *
 * This software is part of the M5 simulator.
 *
 * THIS IS A LEGAL AGREEMENT.  BY DOWNLOADING, USING, COPYING, CREATING
 * DERIVATIVE WORKS, AND/OR DISTRIBUTING THIS SOFTWARE YOU ARE AGREEING
 * TO THESE TERMS AND CONDITIONS.
 *
 * Permission is granted to use, copy, create derivative works and
 * distribute this software and such derivative works for any purpose,
 * so long as (1) the copyright notice above, this grant of permission,
 * and the disclaimer below appear in all copies and derivative works
 * made, (2) the copyright notice above is augmented as appropriate to
 * reflect the addition of any new copyrightable work in a derivative
 * work (e.g., Copyright (c) <Publication Year> Copyright Owner), and (3)
 * the name of MIPS Technologies, Inc. ($(B!H(BMIPS$(B!I(B) is not used in any
 * advertising or publicity pertaining to the use or distribution of
 * this software without specific, written prior authorization.
 *
 * THIS SOFTWARE IS PROVIDED $(B!H(BAS IS.$(B!I(B  MIPS MAKES NO WARRANTIES AND
 * DISCLAIMS ALL WARRANTIES, WHETHER EXPRESS, STATUTORY, IMPLIED OR
 * OTHERWISE, INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND
 * NON-INFRINGEMENT OF THIRD PARTY RIGHTS, REGARDING THIS SOFTWARE.
 * IN NO EVENT SHALL MIPS BE LIABLE FOR ANY DAMAGES, INCLUDING DIRECT,
 * INDIRECT, INCIDENTAL, CONSEQUENTIAL, SPECIAL, OR PUNITIVE DAMAGES OF
 * ANY KIND OR NATURE, ARISING OUT OF OR IN CONNECTION WITH THIS AGREEMENT,
 * THIS SOFTWARE AND/OR THE USE OF THIS SOFTWARE, WHETHER SUCH LIABILITY
 * IS ASSERTED ON THE BASIS OF CONTRACT, TORT (INCLUDING NEGLIGENCE OR
 * STRICT LIABILITY), OR OTHERWISE, EVEN IF MIPS HAS BEEN WARNED OF THE
 * POSSIBILITY OF ANY SUCH LOSS OR DAMAGE IN ADVANCE.
 *
 * Authors: Brett Miller
 */

#include "arch/mips/isa_traits.hh"
#include "arch/mips/dsp.hh"
#include "config/full_system.hh"
#include "cpu/static_inst.hh"
#include "sim/serialize.hh"
#include "base/bitfield.hh"
#include "base/misc.hh"

using namespace MipsISA;
using namespace std;

int32_t
MipsISA::bitrev( int32_t value )
{
    int32_t result = 0;
    int i, shift;

    for( i=0; i<16; i++ )
    {
        shift = 2*i - 15;

        if( shift < 0 )
            result |= (value & 1L<<i) << -shift;
        else
            result |= (value & 1L<<i) >> shift;
    }

    return result;
}

uint64_t
MipsISA::dspSaturate( uint64_t value, int32_t fmt, int32_t sign, uint32_t *overflow )
{
    int64_t svalue;

    svalue = (int64_t)value;

    switch( sign )
    {
      case SIGNED:
        if( svalue > (int64_t)FIXED_SMAX[fmt] )
        {
            *overflow = 1;
            svalue = (int64_t)FIXED_SMAX[fmt];
        }
        else if( svalue < (int64_t)FIXED_SMIN[fmt] )
        {
            *overflow = 1;
            svalue = (int64_t)FIXED_SMIN[fmt];
        }
        break;
      case UNSIGNED:
        if( svalue > (int64_t)FIXED_UMAX[fmt] )
        {
            *overflow = 1;
            svalue = FIXED_UMAX[fmt];
        }
        else if( svalue < (int64_t)FIXED_UMIN[fmt] )
        {
            *overflow = 1;
            svalue = FIXED_UMIN[fmt];
        }
        break;
    }

    return( (uint64_t)svalue );
}

uint64_t
MipsISA::checkOverflow( uint64_t value, int32_t fmt, int32_t sign, uint32_t *overflow )
{
    int64_t svalue;

    svalue = (int64_t)value;

    switch( sign )
    {
      case SIGNED:
        if( svalue > (int64_t)FIXED_SMAX[fmt] || svalue < (int64_t)FIXED_SMIN[fmt] )
            *overflow = 1;
        break;
      case UNSIGNED:
        if( svalue > (int64_t)FIXED_UMAX[fmt] || svalue < (int64_t)FIXED_UMIN[fmt] )
            *overflow = 1;
        break;
    }

    return( (uint64_t)svalue );
}

uint64_t
MipsISA::signExtend( uint64_t value, int32_t fmt )
{
    int32_t signpos = SIMD_NBITS[fmt];
    uint64_t sign = uint64_t(1)<<(signpos-1);
    uint64_t ones = ~(0ULL);

    if( value & sign )
        value |= (ones << signpos); // extend with ones
    else
        value &= (ones >> (64 - signpos)); // extend with zeros

    return value;
}

uint64_t
MipsISA::addHalfLsb( uint64_t value, int32_t lsbpos )
{
    return( value += ULL(1) << (lsbpos-1) );
}

int32_t
MipsISA::dspAbs( int32_t a, int32_t fmt, uint32_t *dspctl )
{
    int i = 0;
    int nvals = SIMD_NVALS[fmt];
    int32_t result;
    int64_t svalue;
    uint32_t ouflag = 0;
    uint64_t a_values[SIMD_MAX_VALS];

    simdUnpack( a, a_values, fmt, SIGNED );

    for( i=0; i<nvals; i++ )
    {
        svalue = (int64_t)a_values[i];

        if( a_values[i] == FIXED_SMIN[fmt] )
        {
            a_values[i] = FIXED_SMAX[fmt];
            ouflag = 1;
        }
        else if( svalue < 0 )
        {
            a_values[i] = uint64_t( 0 - svalue );
        }
    }

    simdPack( a_values, &result, fmt );

    if( ouflag )
        writeDSPControl( dspctl, (ouflag<<4)<<DSP_CTL_POS[DSP_OUFLAG], 1<<DSP_OUFLAG);

    return( result );
}

int32_t
MipsISA::dspAdd( int32_t a, int32_t b, int32_t fmt, int32_t saturate, int32_t sign, uint32_t *dspctl )
{
    int i = 0;
    int nvals = SIMD_NVALS[fmt];
    int32_t result;
    uint32_t ouflag = 0;
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];

    simdUnpack( a, a_values, fmt, sign );
    simdUnpack( b, b_values, fmt, sign );

    for( i=0; i<nvals; i++ )
    {
        if( saturate )
            a_values[i] = dspSaturate( a_values[i] + b_values[i], fmt, sign, &ouflag );
        else
            a_values[i] = checkOverflow( a_values[i] + b_values[i], fmt, sign, &ouflag );
    }

    simdPack( a_values, &result, fmt );

    if( ouflag )
        writeDSPControl( dspctl, (ouflag<<4)<<DSP_CTL_POS[DSP_OUFLAG], 1<<DSP_OUFLAG);

    return( result );
}

int32_t
MipsISA::dspAddh( int32_t a, int32_t b, int32_t fmt, int32_t round, int32_t sign )
{
    int i = 0;
    int nvals = SIMD_NVALS[fmt];
    int32_t result;
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];

    simdUnpack( a, a_values, fmt, sign );
    simdUnpack( b, b_values, fmt, sign );

    for( i=0; i<nvals; i++ )
    {
        if( round )
            a_values[i] = addHalfLsb( a_values[i] + b_values[i], 1 ) >> 1;
        else
            a_values[i] = ( a_values[i] + b_values[i] ) >> 1;
    }

    simdPack( a_values, &result, fmt );

    return( result );
}

int32_t
MipsISA::dspSub( int32_t a, int32_t b, int32_t fmt, int32_t saturate, int32_t sign, uint32_t *dspctl )
{
    int i = 0;
    int nvals = SIMD_NVALS[fmt];
    int32_t result;
    uint32_t ouflag = 0;
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];

    simdUnpack( a, a_values, fmt, sign );
    simdUnpack( b, b_values, fmt, sign );

    for( i=0; i<nvals; i++ )
    {
        if( saturate )
            a_values[i] = dspSaturate( a_values[i] - b_values[i], fmt, sign, &ouflag );
        else
            a_values[i] = checkOverflow( a_values[i] - b_values[i], fmt, sign, &ouflag );
    }

    simdPack( a_values, &result, fmt );

    if( ouflag )
        writeDSPControl( dspctl, (ouflag<<4)<<DSP_CTL_POS[DSP_OUFLAG], 1<<DSP_OUFLAG);

    return( result );
}

int32_t
MipsISA::dspSubh( int32_t a, int32_t b, int32_t fmt, int32_t round, int32_t sign )
{
    int i = 0;
    int nvals = SIMD_NVALS[fmt];
    int32_t result;
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];

    simdUnpack( a, a_values, fmt, sign );
    simdUnpack( b, b_values, fmt, sign );

    for( i=0; i<nvals; i++ )
    {
        if( round )
            a_values[i] = addHalfLsb( a_values[i] - b_values[i], 1 ) >> 1;
        else
            a_values[i] = ( a_values[i] - b_values[i] ) >> 1;
    }

    simdPack( a_values, &result, fmt );

    return( result );
}

int32_t
MipsISA::dspShll( int32_t a, uint32_t sa, int32_t fmt, int32_t saturate, int32_t sign, uint32_t *dspctl )
{
    int i = 0;
    int nvals = SIMD_NVALS[fmt];
    int32_t result;
    uint32_t ouflag = 0;
    uint64_t a_values[SIMD_MAX_VALS];

    sa = bits( sa, SIMD_LOG2N[fmt]-1, 0 );
    simdUnpack( a, a_values, fmt, sign );

    for( i=0; i<nvals; i++ )
    {
        if( saturate )
            a_values[i] = dspSaturate( a_values[i] << sa, fmt, sign, &ouflag );
        else
            a_values[i] = checkOverflow( a_values[i] << sa, fmt, sign, &ouflag );
    }

    simdPack( a_values, &result, fmt );

    if( ouflag )
        writeDSPControl( dspctl, (ouflag<<6)<<DSP_CTL_POS[DSP_OUFLAG], 1<<DSP_OUFLAG);

    return( result );
}

int32_t
MipsISA::dspShrl( int32_t a, uint32_t sa, int32_t fmt, int32_t sign )
{
    int i = 0;
    int nvals = SIMD_NVALS[fmt];
    int32_t result;
    uint64_t a_values[SIMD_MAX_VALS];

    sa = bits( sa, SIMD_LOG2N[fmt]-1, 0 );

    simdUnpack( a, a_values, fmt, UNSIGNED );

    for( i=0; i<nvals; i++ )
        a_values[i] = a_values[i] >> sa;

    simdPack( a_values, &result, fmt );

    return( result );
}

int32_t
MipsISA::dspShra( int32_t a, uint32_t sa, int32_t fmt, int32_t round, int32_t sign, uint32_t *dspctl )
{
    int i = 0;
    int nvals = SIMD_NVALS[fmt];
    int32_t result;
    uint64_t a_values[SIMD_MAX_VALS];

    sa = bits( sa, SIMD_LOG2N[fmt]-1, 0 );

    simdUnpack( a, a_values, fmt, SIGNED );

    for( i=0; i<nvals; i++ )
    {
        if( round )
            a_values[i] = addHalfLsb( a_values[i], sa ) >> sa;
        else
            a_values[i] = a_values[i] >> sa;
    }

    simdPack( a_values, &result, fmt );

    return( result );
}

int32_t
MipsISA::dspMulq( int32_t a, int32_t b, int32_t fmt, int32_t saturate, int32_t round, uint32_t *dspctl )
{
    int i = 0;
    int nvals = SIMD_NVALS[fmt];
    int sa = SIMD_NBITS[fmt];
    int32_t result;
    uint32_t ouflag = 0;
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];
    int64_t temp;

    simdUnpack( a, a_values, fmt, SIGNED );
    simdUnpack( b, b_values, fmt, SIGNED );

    for( i=0; i<nvals; i++ )
    {
        if( round )
            temp = (int64_t)addHalfLsb( a_values[i] * b_values[i] << 1, sa ) >> sa;
        else
            temp = (int64_t)(a_values[i] * b_values[i]) >> (sa - 1);

        if( a_values[i] == FIXED_SMIN[fmt] &&
            b_values[i] == FIXED_SMIN[fmt] )
        {
            ouflag = 1;

            if( saturate )
                temp = FIXED_SMAX[fmt];
        }

        a_values[i] = temp;
    }

    simdPack( a_values, &result, fmt );

    if( ouflag )
        writeDSPControl( dspctl, (ouflag<<5)<<DSP_CTL_POS[DSP_OUFLAG], 1<<DSP_OUFLAG);

    return( result );
}

int32_t
MipsISA::dspMul( int32_t a, int32_t b, int32_t fmt, int32_t saturate, uint32_t *dspctl )
{
    int i = 0;
    int nvals = SIMD_NVALS[fmt];
    int32_t result;