xref: /gem5/src/arch/mips/dsp.cc

/*
 * Copyright (c) 2007 MIPS Technologies, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Brett Miller
 */

#include "arch/mips/dsp.hh"

#include "arch/mips/isa_traits.hh"
#include "base/bitfield.hh"
#include "base/logging.hh"
#include "cpu/static_inst.hh"
#include "sim/serialize.hh"

using namespace MipsISA;
using namespace std;

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

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

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

    return result;
}

uint64_t
MipsISA::dspSaturate(uint64_t value, int32_t fmt, int32_t sign,
    uint32_t *overflow)
{
    int64_t 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 = (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 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 (int 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 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 (int 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 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 (int 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 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 (int 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 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 (int 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 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 (int 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 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 (int 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 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 (int 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 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 (int 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 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, SIGNED);
    simdUnpack(b, b_values, fmt, SIGNED);

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

    simdPack(a_values, &result, fmt);

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

    return result;
}

int32_t
MipsISA::dspMuleu(int32_t a, int32_t b, int32_t mode, uint32_t *dspctl)
{
    int nvals = SIMD_NVALS[SIMD_FMT_PH];
    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, SIMD_FMT_QB, UNSIGNED);
    simdUnpack(b, b_values, SIMD_FMT_PH, UNSIGNED);

    switch (mode) {
      case MODE_L:
        for (int i = 0; i < nvals; i++)
            b_values[i] = dspSaturate(a_values[i + 2] * b_values[i],
                                      SIMD_FMT_PH, UNSIGNED, &ouflag);
        break;
      case MODE_R:
        for (int i = 0; i < nvals; i++)
            b_values[i] = dspSaturate(a_values[i] * b_values[i], SIMD_FMT_PH,
                                      UNSIGNED, &ouflag);
        break;
    }

    simdPack(b_values, &result, SIMD_FMT_PH);

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

    return result;
}

int32_t
MipsISA::dspMuleq(int32_t a, int32_t b, int32_t mode, uint32_t *dspctl)
{
    int nvals = SIMD_NVALS[SIMD_FMT_W];
    int32_t result;
    uint32_t ouflag = 0;
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];
    uint64_t c_values[SIMD_MAX_VALS];

    memset(c_values, 0, sizeof(c_values));

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

    switch (mode) {
      case MODE_L:
        for (int i = 0; i < nvals; i++)
            c_values[i] = dspSaturate(a_values[i + 1] * b_values[i + 1] << 1,
                                       SIMD_FMT_W, SIGNED, &ouflag);
        break;
      case MODE_R:
        for (int i = 0; i < nvals; i++)
            c_values[i] = dspSaturate(a_values[i] * b_values[i] << 1,
                                       SIMD_FMT_W, SIGNED, &ouflag);
        break;
    }

    simdPack(c_values, &result, SIMD_FMT_W);

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

    return result;
}

int64_t
MipsISA::dspDpaq(int64_t dspac, int32_t a, int32_t b, int32_t ac,
    int32_t infmt, int32_t outfmt, int32_t postsat, int32_t mode,
    uint32_t *dspctl)
{
    int nvals = SIMD_NVALS[infmt];
    int64_t result = 0;
    int64_t temp = 0;
    uint32_t ouflag = 0;
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];

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

    for (int i = 0; i < nvals; i++) {
        switch (mode) {
          case MODE_X:
            if (a_values[nvals - 1 - i] == FIXED_SMIN[infmt] &&
                b_values[i] == FIXED_SMIN[infmt]) {
                result += FIXED_SMAX[outfmt];
                ouflag = 1;
            }
            else
                result += a_values[nvals - 1 - i] * b_values[i] << 1;
            break;
          default:
            if (a_values[i] == FIXED_SMIN[infmt] &&
                b_values[i] == FIXED_SMIN[infmt]) {
                result += FIXED_SMAX[outfmt];
                ouflag = 1;
            } else {
                result += a_values[i] * b_values[i] << 1;
            }
            break;
        }
    }

    if (postsat) {
        if (outfmt == SIMD_FMT_L) {
            int signa = bits(dspac, 63, 63);
            int signb = bits(result, 63, 63);

            temp = dspac + result;

            if (signa == signb && bits(temp, 63, 63) != signa) {
                ouflag = 1;
                if (signa)
                    dspac = FIXED_SMIN[outfmt];
                else
                    dspac = FIXED_SMAX[outfmt];
            } else {
                dspac = temp;
            }
        } else {
            dspac = dspSaturate(dspac + result, outfmt, SIGNED, &ouflag);
        }
    } else {
        dspac += result;
    }

    if (ouflag)
        *dspctl = insertBits(*dspctl, 16 + ac, 16 + ac, 1);

    return dspac;
}

int64_t
MipsISA::dspDpsq(int64_t dspac, int32_t a, int32_t b, int32_t ac,
    int32_t infmt, int32_t outfmt, int32_t postsat, int32_t mode,
    uint32_t *dspctl)
{
    int nvals = SIMD_NVALS[infmt];
    int64_t result = 0;
    int64_t temp = 0;
    uint32_t ouflag = 0;
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];

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

    for (int i = 0; i < nvals; i++) {
        switch (mode) {
          case MODE_X:
            if (a_values[nvals - 1 - i] == FIXED_SMIN[infmt] &&
                b_values[i] == FIXED_SMIN[infmt]) {
                result += FIXED_SMAX[outfmt];
                ouflag = 1;
            } else {
                result += a_values[nvals - 1 - i] * b_values[i] << 1;
            }
            break;
          default:
            if (a_values[i] == FIXED_SMIN[infmt] &&
                b_values[i] == FIXED_SMIN[infmt]) {
                result += FIXED_SMAX[outfmt];
                ouflag = 1;
            } else {
                result += a_values[i] * b_values[i] << 1;
            }
            break;
        }
    }

    if (postsat) {
        if (outfmt == SIMD_FMT_L) {
            int signa = bits(dspac, 63, 63);
            int signb = bits(-result, 63, 63);

            temp = dspac - result;

            if (signa == signb && bits(temp, 63, 63) != signa) {
                ouflag = 1;
                if (signa)
                    dspac = FIXED_SMIN[outfmt];
                else
                    dspac = FIXED_SMAX[outfmt];
            } else {
                dspac = temp;
            }
        } else {
            dspac = dspSaturate(dspac - result, outfmt, SIGNED, &ouflag);
        }
    } else {
        dspac -= result;
    }

    if (ouflag)
        *dspctl = insertBits(*dspctl, 16 + ac, 16 + ac, 1);

    return dspac;
}

int64_t
MipsISA::dspDpa(int64_t dspac, int32_t a, int32_t b, int32_t ac,
                int32_t fmt, int32_t sign, int32_t mode)
{
    int nvals = SIMD_NVALS[fmt];
    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 (int i = 0; i < 2; i++) {
        switch (mode) {
          case MODE_L:
            dspac += a_values[nvals - 1 - i] * b_values[nvals - 1 - i];
            break;
          case MODE_R:
            dspac += a_values[nvals - 3 - i] * b_values[nvals - 3 - i];
            break;
          case MODE_X:
            dspac += a_values[nvals - 1 - i] * b_values[i];
            break;
        }
    }

    return dspac;
}

int64_t
MipsISA::dspDps(int64_t dspac, int32_t a, int32_t b, int32_t ac,
                int32_t fmt, int32_t sign, int32_t mode)
{
    int nvals = SIMD_NVALS[fmt];
    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 (int i = 0; i < 2; i++) {
        switch (mode) {
          case MODE_L:
            dspac -= a_values[nvals - 1 - i] * b_values[nvals - 1 - i];
            break;
          case MODE_R:
            dspac -= a_values[nvals - 3 - i] * b_values[nvals - 3 - i];
            break;
          case MODE_X:
            dspac -= a_values[nvals - 1 - i] * b_values[i];
            break;
        }
    }

    return dspac;
}

int64_t
MipsISA::dspMaq(int64_t dspac, int32_t a, int32_t b, int32_t ac,
                 int32_t fmt, int32_t mode, int32_t saturate, uint32_t *dspctl)
{
    int nvals = SIMD_NVALS[fmt - 1];
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];
    int64_t temp = 0;
    uint32_t ouflag = 0;

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

    for (int i = 0; i < nvals; i++) {
        switch (mode) {
          case MODE_L:
            temp = a_values[i + 1] * b_values[i + 1] << 1;
            if (a_values[i + 1] == FIXED_SMIN[fmt] &&
                b_values[i + 1] == FIXED_SMIN[fmt]) {
                temp = (int64_t)FIXED_SMAX[fmt - 1];
                ouflag = 1;
            }
            break;
          case MODE_R:
            temp = a_values[i] * b_values[i] << 1;
            if (a_values[i] == FIXED_SMIN[fmt] &&
                b_values[i] == FIXED_SMIN[fmt]) {
                temp = (int64_t)FIXED_SMAX[fmt - 1];
                ouflag = 1;
            }
            break;
        }

        temp += dspac;

        if (saturate)
            temp = dspSaturate(temp, fmt - 1, SIGNED, &ouflag);
        if (ouflag)
            *dspctl = insertBits(*dspctl, 16 + ac, 16 + ac, 1);
    }

    return temp;
}

int64_t
MipsISA::dspMulsa(int64_t dspac, int32_t a, int32_t b, int32_t ac, int32_t fmt)
{
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];

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

    dspac += a_values[1] * b_values[1] - a_values[0] * b_values[0];

    return dspac;
}

int64_t
MipsISA::dspMulsaq(int64_t dspac, int32_t a, int32_t b, int32_t ac,
    int32_t fmt, uint32_t *dspctl)
{
    int nvals = SIMD_NVALS[fmt];
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];
    int64_t temp[2] = {0, 0};
    uint32_t ouflag = 0;

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

    for (int i = nvals - 1; i > -1; i--) {
        temp[i] = a_values[i] * b_values[i] << 1;
        if (a_values[i] == FIXED_SMIN[fmt] && b_values[i] == FIXED_SMIN[fmt]) {
            temp[i] = FIXED_SMAX[fmt - 1];
            ouflag = 1;
        }
    }

    dspac += temp[1] - temp[0];

    if (ouflag)
        *dspctl = insertBits(*dspctl, 16 + ac, 16 + ac, 1);

    return dspac;
}

void
MipsISA::dspCmp(int32_t a, int32_t b, int32_t fmt, int32_t sign, int32_t op,
    uint32_t *dspctl)
{
    int nvals = SIMD_NVALS[fmt];
    int ccond = 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 (int i = 0; i < nvals; i++) {
        int cc = 0;

        switch (op) {
          case CMP_EQ:
            cc = (a_values[i] == b_values[i]);
            break;
          case CMP_LT:
            cc = (a_values[i] < b_values[i]);
            break;
          case CMP_LE:
            cc = (a_values[i] <= b_values[i]);
            break;
        }

        ccond |= cc << (DSP_CTL_POS[DSP_CCOND] + i);
    }

    writeDSPControl(dspctl, ccond, 1 << DSP_CCOND);
}

int32_t
MipsISA::dspCmpg(int32_t a, int32_t b, int32_t fmt, int32_t sign, int32_t op)
{
    int nvals = SIMD_NVALS[fmt];
    int32_t result = 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 (int i = 0; i < nvals; i++) {
        int cc = 0;

        switch (op) {
          case CMP_EQ:
            cc = (a_values[i] == b_values[i]);
            break;
          case CMP_LT:
            cc = (a_values[i] < b_values[i]);
            break;
          case CMP_LE:
            cc = (a_values[i] <= b_values[i]);
            break;
        }

        result |= cc << i;
    }

    return result;
}

int32_t
MipsISA::dspCmpgd(int32_t a, int32_t b, int32_t fmt, int32_t sign, int32_t op,
    uint32_t *dspctl)
{
    int nvals = SIMD_NVALS[fmt];
    int32_t result = 0;
    int ccond = 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 (int i = 0; i < nvals; i++) {
        int cc = 0;

        switch (op) {
          case CMP_EQ:
            cc = (a_values[i] == b_values[i]);
            break;
          case CMP_LT:
            cc = (a_values[i] < b_values[i]);
            break;
          case CMP_LE:
            cc = (a_values[i] <= b_values[i]);
            break;
        }

        result |= cc << i;
        ccond |= cc << (DSP_CTL_POS[DSP_CCOND] + i);
    }

    writeDSPControl(dspctl, ccond, 1 << DSP_CCOND);

    return result;
}

int32_t
MipsISA::dspPrece(int32_t a, int32_t infmt, int32_t insign, int32_t outfmt,
    int32_t outsign, int32_t mode)
{
    int sa = 0;
    int ninvals = SIMD_NVALS[infmt];
    int noutvals = SIMD_NVALS[outfmt];
    int32_t result;
    uint64_t in_values[SIMD_MAX_VALS];
    uint64_t out_values[SIMD_MAX_VALS];

    if (insign == SIGNED && outsign == SIGNED)
      sa = SIMD_NBITS[infmt];
    else if (insign == UNSIGNED && outsign == SIGNED)
      sa = SIMD_NBITS[infmt] - 1;
    else if (insign == UNSIGNED && outsign == UNSIGNED)
      sa = 0;

    simdUnpack(a, in_values, infmt, insign);

    for (int i = 0; i<noutvals; i++) {
        switch (mode) {
          case MODE_L:
            out_values[i] = in_values[i + (ninvals >> 1)] << sa;
            break;
          case MODE_R:
            out_values[i] = in_values[i] << sa;
            break;
          case MODE_LA:
            out_values[i] = in_values[(i << 1) + 1] << sa;
            break;
          case MODE_RA:
            out_values[i] = in_values[i << 1] << sa;
            break;
        }
    }

    simdPack(out_values, &result, outfmt);

    return result;
}

int32_t
MipsISA::dspPrecrqu(int32_t a, int32_t b, uint32_t *dspctl)
{
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];
    uint64_t r_values[SIMD_MAX_VALS];
    uint32_t ouflag = 0;
    int32_t result = 0;

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

    for (int i = 0; i<2; i++) {
        r_values[i] =
            dspSaturate((int64_t)b_values[i] >> (SIMD_NBITS[SIMD_FMT_QB] - 1),
                        SIMD_FMT_QB, UNSIGNED, &ouflag);
        r_values[i + 2] =
            dspSaturate((int64_t)a_values[i] >> (SIMD_NBITS[SIMD_FMT_QB] - 1),
                        SIMD_FMT_QB, UNSIGNED, &ouflag);
    }

    simdPack(r_values, &result, SIMD_FMT_QB);

    if (ouflag)
        *dspctl = insertBits(*dspctl, 22, 22, 1);

    return result;
}

int32_t
MipsISA::dspPrecrq(int32_t a, int32_t b, int32_t fmt, uint32_t *dspctl)
{
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];
    uint64_t r_values[SIMD_MAX_VALS];
    uint32_t ouflag = 0;
    int32_t result;

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

    r_values[1] = dspSaturate((int64_t)addHalfLsb(a_values[0], 16) >> 16,
                              fmt + 1, SIGNED, &ouflag);
    r_values[0] = dspSaturate((int64_t)addHalfLsb(b_values[0], 16) >> 16,
                              fmt + 1, SIGNED, &ouflag);

    simdPack(r_values, &result, fmt + 1);

    if (ouflag)
        *dspctl = insertBits(*dspctl, 22, 22, 1);

    return result;
}

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

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

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

    simdPack(c_values, &result, fmt + 1);

    return result;
}

int32_t
MipsISA::dspPick(int32_t a, int32_t b, int32_t fmt, uint32_t *dspctl)
{
    int nvals = SIMD_NVALS[fmt];
    int32_t result;
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];
    uint64_t c_values[SIMD_MAX_VALS];

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

    for (int i = 0; i < nvals; i++) {
        int condbit = DSP_CTL_POS[DSP_CCOND] + i;
        if (bits(*dspctl, condbit, condbit) == 1)
            c_values[i] = a_values[i];
        else
            c_values[i] = b_values[i];
    }

    simdPack(c_values, &result, fmt);

    return result;
}

int32_t
MipsISA::dspPack(int32_t a, int32_t b, int32_t fmt)
{
    int32_t result;
    uint64_t a_values[SIMD_MAX_VALS];
    uint64_t b_values[SIMD_MAX_VALS];
    uint64_t c_values[SIMD_MAX_VALS];

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

    c_values[0] = b_values[1];
    c_values[1] = a_values[0];

    simdPack(c_values, &result, fmt);

    return result;
}

int32_t
MipsISA::dspExtr(int64_t dspac, int32_t fmt, int32_t sa, int32_t round,
    int32_t saturate, uint32_t *dspctl)
{
    int32_t result = 0;
    uint32_t ouflag = 0;
    int64_t temp = 0;

    sa = bits(sa, 4, 0);

    if (sa > 0) {
        if (round) {
            temp = (int64_t)addHalfLsb(dspac, sa);

            if (dspac > 0 && temp < 0) {
                ouflag = 1;
                if (saturate)
                    temp = FIXED_SMAX[SIMD_FMT_L];
            }
            temp = temp >> sa;
        } else {
            temp = dspac >> sa;
        }
    } else {
        temp = dspac;
    }

    dspac = checkOverflow(dspac, fmt, SIGNED, &ouflag);

    if (ouflag) {
        *dspctl = insertBits(*dspctl, 23, 23, ouflag);

        if (saturate)
            result = (int32_t)dspSaturate(temp, fmt, SIGNED, &ouflag);
        else
            result = (int32_t)temp;
    } else {
        result = (int32_t)temp;
    }

    return result;
}

int32_t
MipsISA::dspExtp(int64_t dspac, int32_t size, uint32_t *dspctl)
{
    int32_t pos = 0;
    int32_t result = 0;

    pos = bits(*dspctl, 5, 0);
    size = bits(size, 4, 0);

    if (pos - (size + 1) >= -1) {
        result = bits(dspac, pos, pos - size);
        *dspctl = insertBits(*dspctl, 14, 14, 0);
    } else {
        result = 0;
        *dspctl = insertBits(*dspctl, 14, 14, 1);
    }

    return result;
}

int32_t
MipsISA::dspExtpd(int64_t dspac, int32_t size, uint32_t *dspctl)
{
    int32_t pos = 0;
    int32_t result = 0;

    pos = bits(*dspctl, 5, 0);
    size = bits(size, 4, 0);

    if (pos - (size + 1) >= -1) {
        result = bits(dspac, pos, pos - size);
        *dspctl = insertBits(*dspctl, 14, 14, 0);
        if (pos - (size + 1) >= 0)
            *dspctl = insertBits(*dspctl, 5, 0, pos - (size + 1));
        else if ((pos - (size + 1)) == -1)
            *dspctl = insertBits(*dspctl, 5, 0, 63);
    } else {
        result = 0;
        *dspctl = insertBits(*dspctl, 14, 14, 1);
    }

    return result;
}

void
MipsISA::simdPack(uint64_t *values_ptr, int32_t *reg, int32_t fmt)
{
    int nvals = SIMD_NVALS[fmt];
    int nbits = SIMD_NBITS[fmt];

    *reg = 0;

    for (int i = 0; i < nvals; i++)
        *reg |= (int32_t)bits(values_ptr[i], nbits - 1, 0) << nbits * i;
}

void
MipsISA::simdUnpack(int32_t reg, uint64_t *values_ptr, int32_t fmt, int32_t sign)
{
    int nvals = SIMD_NVALS[fmt];
    int nbits = SIMD_NBITS[fmt];

    switch (sign) {
      case SIGNED:
        for (int i = 0; i < nvals; i++) {
            uint64_t tmp = (uint64_t)bits(reg, nbits * (i + 1) - 1, nbits * i);
            values_ptr[i] = signExtend(tmp, fmt);
        }
        break;
      case UNSIGNED:
        for (int i = 0; i < nvals; i++) {
            values_ptr[i] =
                (uint64_t)bits(reg, nbits * (i + 1) - 1, nbits * i);
        }
        break;
    }
}

void
MipsISA::writeDSPControl(uint32_t *dspctl, uint32_t value, uint32_t mask)
{
    uint32_t fmask = 0;

    if (mask & 0x01) fmask |= DSP_CTL_MASK[DSP_POS];
    if (mask & 0x02) fmask |= DSP_CTL_MASK[DSP_SCOUNT];
    if (mask & 0x04) fmask |= DSP_CTL_MASK[DSP_C];
    if (mask & 0x08) fmask |= DSP_CTL_MASK[DSP_OUFLAG];
    if (mask & 0x10) fmask |= DSP_CTL_MASK[DSP_CCOND];
    if (mask & 0x20) fmask |= DSP_CTL_MASK[DSP_EFI];

    *dspctl &= ~fmask;
    value &= fmask;
    *dspctl |= value;
}

uint32_t
MipsISA::readDSPControl(uint32_t *dspctl, uint32_t mask)
{
    uint32_t fmask = 0;

    if (mask & 0x01) fmask |= DSP_CTL_MASK[DSP_POS];
    if (mask & 0x02) fmask |= DSP_CTL_MASK[DSP_SCOUNT];
    if (mask & 0x04) fmask |= DSP_CTL_MASK[DSP_C];
    if (mask & 0x08) fmask |= DSP_CTL_MASK[DSP_OUFLAG];
    if (mask & 0x10) fmask |= DSP_CTL_MASK[DSP_CCOND];
    if (mask & 0x20) fmask |= DSP_CTL_MASK[DSP_EFI];

    return *dspctl & fmask;
}