reg_ld_str.c

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/*---------------------------------------------------------------------------+
 |  reg_ld_str.c                                                             |
 |                                                                           |
 | All of the functions which transfer data between user memory and FPU_REGs.|
 |                                                                           |
 | Copyright (C) 1992,1993,1994,1996,1997                                    |
 |                  W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
 |                  E-mail   [email protected]                              |
 |                                                                           |
 |                                                                           |
 +---------------------------------------------------------------------------*/

/*---------------------------------------------------------------------------+
 | Note:                                                                     |
 |    The file contains code which accesses user memory.                     |
 |    Emulator static data may change when user memory is accessed, due to   |
 |    other processes using the emulator while swapping is in progress.      |
 +---------------------------------------------------------------------------*/

#include "fpu_emu.h"

#include <asm/uaccess.h>

#include "fpu_system.h"
#include "exception.h"
#include "reg_constant.h"
#include "control_w.h"
#include "status_w.h"

#define DOUBLE_Emax 1023    /* largest valid exponent */
#define DOUBLE_Ebias 1023
#define DOUBLE_Emin (-1022) /* smallest valid exponent */

#define SINGLE_Emax 127     /* largest valid exponent */
#define SINGLE_Ebias 127
#define SINGLE_Emin (-126)  /* smallest valid exponent */

static u_char normalize_no_excep(FPU_REG *r, int exp, int sign)
{
    u_char tag;

    setexponent16(r, exp);

    tag = FPU_normalize_nuo(r);
    stdexp(r);
    if (sign)
        setnegative(r);

    return tag;
}

int FPU_tagof(FPU_REG *ptr)
{
    int exp;

    exp = exponent16(ptr) & 0x7fff;
    if (exp == 0) {
        if (!(ptr->sigh | ptr->sigl)) {
            return TAG_Zero;
        }
        /* The number is a de-normal or pseudodenormal. */
        return TAG_Special;
    }

    if (exp == 0x7fff) {
        /* Is an Infinity, a NaN, or an unsupported data type. */
        return TAG_Special;
    }

    if (!(ptr->sigh & 0x80000000)) {
        /* Unsupported data type. */
        /* Valid numbers have the ms bit set to 1. */
        /* Unnormal. */
        return TAG_Special;
    }

    return TAG_Valid;
}

/* Get a long double from user memory */
int FPU_load_extended(long double __user *s, int stnr)
{
    FPU_REG *sti_ptr = &st(stnr);

    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_READ, s, 10);
    __copy_from_user(sti_ptr, s, 10);
    RE_ENTRANT_CHECK_ON;

    return FPU_tagof(sti_ptr);
}

/* Get a double from user memory */
int FPU_load_double(double __user *dfloat, FPU_REG *loaded_data)
{
    int exp, tag, negative;
    unsigned m64, l64;

    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_READ, dfloat, 8);
    FPU_get_user(m64, 1 + (unsigned long __user *)dfloat);
    FPU_get_user(l64, (unsigned long __user *)dfloat);
    RE_ENTRANT_CHECK_ON;

    negative = (m64 & 0x80000000) ? SIGN_Negative : SIGN_Positive;
    exp = ((m64 & 0x7ff00000) >> 20) - DOUBLE_Ebias + EXTENDED_Ebias;
    m64 &= 0xfffff;
    if (exp > DOUBLE_Emax + EXTENDED_Ebias) {
        /* Infinity or NaN */
        if ((m64 == 0) && (l64 == 0)) {
            /* +- infinity */
            loaded_data->sigh = 0x80000000;
            loaded_data->sigl = 0x00000000;
            exp = EXP_Infinity + EXTENDED_Ebias;
            tag = TAG_Special;
        } else {
            /* Must be a signaling or quiet NaN */
            exp = EXP_NaN + EXTENDED_Ebias;
            loaded_data->sigh = (m64 << 11) | 0x80000000;
            loaded_data->sigh |= l64 >> 21;
            loaded_data->sigl = l64 << 11;
            tag = TAG_Special;  /* The calling function must look for NaNs */
        }
    } else if (exp < DOUBLE_Emin + EXTENDED_Ebias) {
        /* Zero or de-normal */
        if ((m64 == 0) && (l64 == 0)) {
            /* Zero */
            reg_copy(&CONST_Z, loaded_data);
            exp = 0;
            tag = TAG_Zero;
        } else {
            /* De-normal */
            loaded_data->sigh = m64 << 11;
            loaded_data->sigh |= l64 >> 21;
            loaded_data->sigl = l64 << 11;

            return normalize_no_excep(loaded_data, DOUBLE_Emin,
                          negative)
                | (denormal_operand() < 0 ? FPU_Exception : 0);
        }
    } else {
        loaded_data->sigh = (m64 << 11) | 0x80000000;
        loaded_data->sigh |= l64 >> 21;
        loaded_data->sigl = l64 << 11;

        tag = TAG_Valid;
    }

    setexponent16(loaded_data, exp | negative);

    return tag;
}

/* Get a float from user memory */
int FPU_load_single(float __user *single, FPU_REG *loaded_data)
{
    unsigned m32;
    int exp, tag, negative;

    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_READ, single, 4);
    FPU_get_user(m32, (unsigned long __user *)single);
    RE_ENTRANT_CHECK_ON;

    negative = (m32 & 0x80000000) ? SIGN_Negative : SIGN_Positive;

    if (!(m32 & 0x7fffffff)) {
        /* Zero */
        reg_copy(&CONST_Z, loaded_data);
        addexponent(loaded_data, negative);
        return TAG_Zero;
    }
    exp = ((m32 & 0x7f800000) >> 23) - SINGLE_Ebias + EXTENDED_Ebias;
    m32 = (m32 & 0x7fffff) << 8;
    if (exp < SINGLE_Emin + EXTENDED_Ebias) {
        /* De-normals */
        loaded_data->sigh = m32;
        loaded_data->sigl = 0;

        return normalize_no_excep(loaded_data, SINGLE_Emin, negative)
            | (denormal_operand() < 0 ? FPU_Exception : 0);
    } else if (exp > SINGLE_Emax + EXTENDED_Ebias) {
        /* Infinity or NaN */
        if (m32 == 0) {
            /* +- infinity */
            loaded_data->sigh = 0x80000000;
            loaded_data->sigl = 0x00000000;
            exp = EXP_Infinity + EXTENDED_Ebias;
            tag = TAG_Special;
        } else {
            /* Must be a signaling or quiet NaN */
            exp = EXP_NaN + EXTENDED_Ebias;
            loaded_data->sigh = m32 | 0x80000000;
            loaded_data->sigl = 0;
            tag = TAG_Special;  /* The calling function must look for NaNs */
        }
    } else {
        loaded_data->sigh = m32 | 0x80000000;
        loaded_data->sigl = 0;
        tag = TAG_Valid;
    }

    setexponent16(loaded_data, exp | negative); /* Set the sign. */

    return tag;
}

/* Get a long long from user memory */
int FPU_load_int64(long long __user *_s)
{
    long long s;
    int sign;
    FPU_REG *st0_ptr = &st(0);

    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_READ, _s, 8);
    if (copy_from_user(&s, _s, 8))
        FPU_abort;
    RE_ENTRANT_CHECK_ON;

    if (s == 0) {
        reg_copy(&CONST_Z, st0_ptr);
        return TAG_Zero;
    }

    if (s > 0)
        sign = SIGN_Positive;
    else {
        s = -s;
        sign = SIGN_Negative;
    }

    significand(st0_ptr) = s;

    return normalize_no_excep(st0_ptr, 63, sign);
}

/* Get a long from user memory */
int FPU_load_int32(long __user *_s, FPU_REG *loaded_data)
{
    long s;
    int negative;

    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_READ, _s, 4);
    FPU_get_user(s, _s);
    RE_ENTRANT_CHECK_ON;

    if (s == 0) {
        reg_copy(&CONST_Z, loaded_data);
        return TAG_Zero;
    }

    if (s > 0)
        negative = SIGN_Positive;
    else {
        s = -s;
        negative = SIGN_Negative;
    }

    loaded_data->sigh = s;
    loaded_data->sigl = 0;

    return normalize_no_excep(loaded_data, 31, negative);
}

/* Get a short from user memory */
int FPU_load_int16(short __user *_s, FPU_REG *loaded_data)
{
    int s, negative;

    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_READ, _s, 2);
    /* Cast as short to get the sign extended. */
    FPU_get_user(s, _s);
    RE_ENTRANT_CHECK_ON;

    if (s == 0) {
        reg_copy(&CONST_Z, loaded_data);
        return TAG_Zero;
    }

    if (s > 0)
        negative = SIGN_Positive;
    else {
        s = -s;
        negative = SIGN_Negative;
    }

    loaded_data->sigh = s << 16;
    loaded_data->sigl = 0;

    return normalize_no_excep(loaded_data, 15, negative);
}

/* Get a packed bcd array from user memory */
int FPU_load_bcd(u_char __user *s)
{
    FPU_REG *st0_ptr = &st(0);
    int pos;
    u_char bcd;
    long long l = 0;
    int sign;

    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_READ, s, 10);
    RE_ENTRANT_CHECK_ON;
    for (pos = 8; pos >= 0; pos--) {
        l *= 10;
        RE_ENTRANT_CHECK_OFF;
        FPU_get_user(bcd, s + pos);
        RE_ENTRANT_CHECK_ON;
        l += bcd >> 4;
        l *= 10;
        l += bcd & 0x0f;
    }

    RE_ENTRANT_CHECK_OFF;
    FPU_get_user(sign, s + 9);
    sign = sign & 0x80 ? SIGN_Negative : SIGN_Positive;
    RE_ENTRANT_CHECK_ON;

    if (l == 0) {
        reg_copy(&CONST_Z, st0_ptr);
        addexponent(st0_ptr, sign); /* Set the sign. */
        return TAG_Zero;
    } else {
        significand(st0_ptr) = l;
        return normalize_no_excep(st0_ptr, 63, sign);
    }
}

/*===========================================================================*/

/* Put a long double into user memory */
int FPU_store_extended(FPU_REG *st0_ptr, u_char st0_tag,
               long double __user * d)
{
    /*
       The only exception raised by an attempt to store to an
       extended format is the Invalid Stack exception, i.e.
       attempting to store from an empty register.
     */

    if (st0_tag != TAG_Empty) {
        RE_ENTRANT_CHECK_OFF;
        FPU_access_ok(VERIFY_WRITE, d, 10);

        FPU_put_user(st0_ptr->sigl, (unsigned long __user *)d);
        FPU_put_user(st0_ptr->sigh,
                 (unsigned long __user *)((u_char __user *) d + 4));
        FPU_put_user(exponent16(st0_ptr),
                 (unsigned short __user *)((u_char __user *) d +
                               8));
        RE_ENTRANT_CHECK_ON;

        return 1;
    }

    /* Empty register (stack underflow) */
    EXCEPTION(EX_StackUnder);
    if (control_word & CW_Invalid) {
        /* The masked response */
        /* Put out the QNaN indefinite */
        RE_ENTRANT_CHECK_OFF;
        FPU_access_ok(VERIFY_WRITE, d, 10);
        FPU_put_user(0, (unsigned long __user *)d);
        FPU_put_user(0xc0000000, 1 + (unsigned long __user *)d);
        FPU_put_user(0xffff, 4 + (short __user *)d);
        RE_ENTRANT_CHECK_ON;
        return 1;
    } else
        return 0;

}

/* Put a double into user memory */
int FPU_store_double(FPU_REG *st0_ptr, u_char st0_tag, double __user *dfloat)
{
    unsigned long l[2];
    unsigned long increment = 0;    /* avoid gcc warnings */
    int precision_loss;
    int exp;
    FPU_REG tmp;

    l[0] = 0;
    l[1] = 0;
    if (st0_tag == TAG_Valid) {
        reg_copy(st0_ptr, &tmp);
        exp = exponent(&tmp);

        if (exp < DOUBLE_Emin) {    /* It may be a denormal */
            addexponent(&tmp, -DOUBLE_Emin + 52);   /* largest exp to be 51 */
denormal_arg:
            if ((precision_loss = FPU_round_to_int(&tmp, st0_tag))) {
#ifdef PECULIAR_486
                /* Did it round to a non-denormal ? */
                /* This behaviour might be regarded as peculiar, it appears
                   that the 80486 rounds to the dest precision, then
                   converts to decide underflow. */
                if (!
                    ((tmp.sigh == 0x00100000) && (tmp.sigl == 0)
                     && (st0_ptr->sigl & 0x000007ff)))
#endif /* PECULIAR_486 */
                {
                    EXCEPTION(EX_Underflow);
                    /* This is a special case: see sec 16.2.5.1 of
                       the 80486 book */
                    if (!(control_word & CW_Underflow))
                        return 0;
                }
                EXCEPTION(precision_loss);
                if (!(control_word & CW_Precision))
                    return 0;
            }
            l[0] = tmp.sigl;
            l[1] = tmp.sigh;
        } else {
            if (tmp.sigl & 0x000007ff) {
                precision_loss = 1;
                switch (control_word & CW_RC) {
                case RC_RND:
                    /* Rounding can get a little messy.. */
                    increment = ((tmp.sigl & 0x7ff) > 0x400) |  /* nearest */
                        ((tmp.sigl & 0xc00) == 0xc00);  /* odd -> even */
                    break;
                case RC_DOWN:   /* towards -infinity */
                    increment =
                        signpositive(&tmp) ? 0 : tmp.
                        sigl & 0x7ff;
                    break;
                case RC_UP: /* towards +infinity */
                    increment =
                        signpositive(&tmp) ? tmp.
                        sigl & 0x7ff : 0;
                    break;
                case RC_CHOP:
                    increment = 0;
                    break;
                }

                /* Truncate the mantissa */
                tmp.sigl &= 0xfffff800;

                if (increment) {
                    if (tmp.sigl >= 0xfffff800) {
                        /* the sigl part overflows */
                        if (tmp.sigh == 0xffffffff) {
                            /* The sigh part overflows */
                            tmp.sigh = 0x80000000;
                            exp++;
                            if (exp >= EXP_OVER)
                                goto overflow;
                        } else {
                            tmp.sigh++;
                        }
                        tmp.sigl = 0x00000000;
                    } else {
                        /* We only need to increment sigl */
                        tmp.sigl += 0x00000800;
                    }
                }
            } else
                precision_loss = 0;

            l[0] = (tmp.sigl >> 11) | (tmp.sigh << 21);
            l[1] = ((tmp.sigh >> 11) & 0xfffff);

            if (exp > DOUBLE_Emax) {
                  overflow:
                EXCEPTION(EX_Overflow);
                if (!(control_word & CW_Overflow))
                    return 0;
                set_precision_flag_up();
                if (!(control_word & CW_Precision))
                    return 0;

                /* This is a special case: see sec 16.2.5.1 of the 80486 book */
                /* Overflow to infinity */
                l[1] = 0x7ff00000;  /* Set to + INF */
            } else {
                if (precision_loss) {
                    if (increment)
                        set_precision_flag_up();
                    else
                        set_precision_flag_down();
                }
                /* Add the exponent */
                l[1] |= (((exp + DOUBLE_Ebias) & 0x7ff) << 20);
            }
        }
    } else if (st0_tag == TAG_Zero) {
        /* Number is zero */
    } else if (st0_tag == TAG_Special) {
        st0_tag = FPU_Special(st0_ptr);
        if (st0_tag == TW_Denormal) {
            /* A denormal will always underflow. */
#ifndef PECULIAR_486
            /* An 80486 is supposed to be able to generate
               a denormal exception here, but... */
            /* Underflow has priority. */
            if (control_word & CW_Underflow)
                denormal_operand();
#endif /* PECULIAR_486 */
            reg_copy(st0_ptr, &tmp);
            goto denormal_arg;
        } else if (st0_tag == TW_Infinity) {
            l[1] = 0x7ff00000;
        } else if (st0_tag == TW_NaN) {
            /* Is it really a NaN ? */
            if ((exponent(st0_ptr) == EXP_OVER)
                && (st0_ptr->sigh & 0x80000000)) {
                /* See if we can get a valid NaN from the FPU_REG */
                l[0] =
                    (st0_ptr->sigl >> 11) | (st0_ptr->
                                 sigh << 21);
                l[1] = ((st0_ptr->sigh >> 11) & 0xfffff);
                if (!(st0_ptr->sigh & 0x40000000)) {
                    /* It is a signalling NaN */
                    EXCEPTION(EX_Invalid);
                    if (!(control_word & CW_Invalid))
                        return 0;
                    l[1] |= (0x40000000 >> 11);
                }
                l[1] |= 0x7ff00000;
            } else {
                /* It is an unsupported data type */
                EXCEPTION(EX_Invalid);
                if (!(control_word & CW_Invalid))
                    return 0;
                l[1] = 0xfff80000;
            }
        }
    } else if (st0_tag == TAG_Empty) {
        /* Empty register (stack underflow) */
        EXCEPTION(EX_StackUnder);
        if (control_word & CW_Invalid) {
            /* The masked response */
            /* Put out the QNaN indefinite */
            RE_ENTRANT_CHECK_OFF;
            FPU_access_ok(VERIFY_WRITE, dfloat, 8);
            FPU_put_user(0, (unsigned long __user *)dfloat);
            FPU_put_user(0xfff80000,
                     1 + (unsigned long __user *)dfloat);
            RE_ENTRANT_CHECK_ON;
            return 1;
        } else
            return 0;
    }
    if (getsign(st0_ptr))
        l[1] |= 0x80000000;

    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_WRITE, dfloat, 8);
    FPU_put_user(l[0], (unsigned long __user *)dfloat);
    FPU_put_user(l[1], 1 + (unsigned long __user *)dfloat);
    RE_ENTRANT_CHECK_ON;

    return 1;
}

/* Put a float into user memory */
int FPU_store_single(FPU_REG *st0_ptr, u_char st0_tag, float __user *single)
{
    long templ = 0;
    unsigned long increment = 0;    /* avoid gcc warnings */
    int precision_loss;
    int exp;
    FPU_REG tmp;

    if (st0_tag == TAG_Valid) {

        reg_copy(st0_ptr, &tmp);
        exp = exponent(&tmp);

        if (exp < SINGLE_Emin) {
            addexponent(&tmp, -SINGLE_Emin + 23);   /* largest exp to be 22 */

              denormal_arg:

            if ((precision_loss = FPU_round_to_int(&tmp, st0_tag))) {
#ifdef PECULIAR_486
                /* Did it round to a non-denormal ? */
                /* This behaviour might be regarded as peculiar, it appears
                   that the 80486 rounds to the dest precision, then
                   converts to decide underflow. */
                if (!((tmp.sigl == 0x00800000) &&
                      ((st0_ptr->sigh & 0x000000ff)
                       || st0_ptr->sigl)))
#endif /* PECULIAR_486 */
                {
                    EXCEPTION(EX_Underflow);
                    /* This is a special case: see sec 16.2.5.1 of
                       the 80486 book */
                    if (!(control_word & CW_Underflow))
                        return 0;
                }
                EXCEPTION(precision_loss);
                if (!(control_word & CW_Precision))
                    return 0;
            }
            templ = tmp.sigl;
        } else {
            if (tmp.sigl | (tmp.sigh & 0x000000ff)) {
                unsigned long sigh = tmp.sigh;
                unsigned long sigl = tmp.sigl;

                precision_loss = 1;
                switch (control_word & CW_RC) {
                case RC_RND:
                    increment = ((sigh & 0xff) > 0x80)  /* more than half */
                        ||(((sigh & 0xff) == 0x80) && sigl) /* more than half */
                        ||((sigh & 0x180) == 0x180);    /* round to even */
                    break;
                case RC_DOWN:   /* towards -infinity */
                    increment = signpositive(&tmp)
                        ? 0 : (sigl | (sigh & 0xff));
                    break;
                case RC_UP: /* towards +infinity */
                    increment = signpositive(&tmp)
                        ? (sigl | (sigh & 0xff)) : 0;
                    break;
                case RC_CHOP:
                    increment = 0;
                    break;
                }

                /* Truncate part of the mantissa */
                tmp.sigl = 0;

                if (increment) {
                    if (sigh >= 0xffffff00) {
                        /* The sigh part overflows */
                        tmp.sigh = 0x80000000;
                        exp++;
                        if (exp >= EXP_OVER)
                            goto overflow;
                    } else {
                        tmp.sigh &= 0xffffff00;
                        tmp.sigh += 0x100;
                    }
                } else {
                    tmp.sigh &= 0xffffff00; /* Finish the truncation */
                }
            } else
                precision_loss = 0;

            templ = (tmp.sigh >> 8) & 0x007fffff;

            if (exp > SINGLE_Emax) {
                  overflow:
                EXCEPTION(EX_Overflow);
                if (!(control_word & CW_Overflow))
                    return 0;
                set_precision_flag_up();
                if (!(control_word & CW_Precision))
                    return 0;

                /* This is a special case: see sec 16.2.5.1 of the 80486 book. */
                /* Masked response is overflow to infinity. */
                templ = 0x7f800000;
            } else {
                if (precision_loss) {
                    if (increment)
                        set_precision_flag_up();
                    else
                        set_precision_flag_down();
                }
                /* Add the exponent */
                templ |= ((exp + SINGLE_Ebias) & 0xff) << 23;
            }
        }
    } else if (st0_tag == TAG_Zero) {
        templ = 0;
    } else if (st0_tag == TAG_Special) {
        st0_tag = FPU_Special(st0_ptr);
        if (st0_tag == TW_Denormal) {
            reg_copy(st0_ptr, &tmp);

            /* A denormal will always underflow. */
#ifndef PECULIAR_486
            /* An 80486 is supposed to be able to generate
               a denormal exception here, but... */
            /* Underflow has priority. */
            if (control_word & CW_Underflow)
                denormal_operand();
#endif /* PECULIAR_486 */
            goto denormal_arg;
        } else if (st0_tag == TW_Infinity) {
            templ = 0x7f800000;
        } else if (st0_tag == TW_NaN) {
            /* Is it really a NaN ? */
            if ((exponent(st0_ptr) == EXP_OVER)
                && (st0_ptr->sigh & 0x80000000)) {
                /* See if we can get a valid NaN from the FPU_REG */
                templ = st0_ptr->sigh >> 8;
                if (!(st0_ptr->sigh & 0x40000000)) {
                    /* It is a signalling NaN */
                    EXCEPTION(EX_Invalid);
                    if (!(control_word & CW_Invalid))
                        return 0;
                    templ |= (0x40000000 >> 8);
                }
                templ |= 0x7f800000;
            } else {
                /* It is an unsupported data type */
                EXCEPTION(EX_Invalid);
                if (!(control_word & CW_Invalid))
                    return 0;
                templ = 0xffc00000;
            }
        }
#ifdef PARANOID
        else {
            EXCEPTION(EX_INTERNAL | 0x164);
            return 0;
        }
#endif
    } else if (st0_tag == TAG_Empty) {
        /* Empty register (stack underflow) */
        EXCEPTION(EX_StackUnder);
        if (control_word & EX_Invalid) {
            /* The masked response */
            /* Put out the QNaN indefinite */
            RE_ENTRANT_CHECK_OFF;
            FPU_access_ok(VERIFY_WRITE, single, 4);
            FPU_put_user(0xffc00000,
                     (unsigned long __user *)single);
            RE_ENTRANT_CHECK_ON;
            return 1;
        } else
            return 0;
    }
#ifdef PARANOID
    else {
        EXCEPTION(EX_INTERNAL | 0x163);
        return 0;
    }
#endif
    if (getsign(st0_ptr))
        templ |= 0x80000000;

    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_WRITE, single, 4);
    FPU_put_user(templ, (unsigned long __user *)single);
    RE_ENTRANT_CHECK_ON;

    return 1;
}

/* Put a long long into user memory */
int FPU_store_int64(FPU_REG *st0_ptr, u_char st0_tag, long long __user *d)
{
    FPU_REG t;
    long long tll;
    int precision_loss;

    if (st0_tag == TAG_Empty) {
        /* Empty register (stack underflow) */
        EXCEPTION(EX_StackUnder);
        goto invalid_operand;
    } else if (st0_tag == TAG_Special) {
        st0_tag = FPU_Special(st0_ptr);
        if ((st0_tag == TW_Infinity) || (st0_tag == TW_NaN)) {
            EXCEPTION(EX_Invalid);
            goto invalid_operand;
        }
    }

    reg_copy(st0_ptr, &t);
    precision_loss = FPU_round_to_int(&t, st0_tag);
    ((long *)&tll)[0] = t.sigl;
    ((long *)&tll)[1] = t.sigh;
    if ((precision_loss == 1) ||
        ((t.sigh & 0x80000000) &&
         !((t.sigh == 0x80000000) && (t.sigl == 0) && signnegative(&t)))) {
        EXCEPTION(EX_Invalid);
        /* This is a special case: see sec 16.2.5.1 of the 80486 book */
          invalid_operand:
        if (control_word & EX_Invalid) {
            /* Produce something like QNaN "indefinite" */
            tll = 0x8000000000000000LL;
        } else
            return 0;
    } else {
        if (precision_loss)
            set_precision_flag(precision_loss);
        if (signnegative(&t))
            tll = -tll;
    }

    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_WRITE, d, 8);
    if (copy_to_user(d, &tll, 8))
        FPU_abort;
    RE_ENTRANT_CHECK_ON;

    return 1;
}

/* Put a long into user memory */
int FPU_store_int32(FPU_REG *st0_ptr, u_char st0_tag, long __user *d)
{
    FPU_REG t;
    int precision_loss;

    if (st0_tag == TAG_Empty) {
        /* Empty register (stack underflow) */
        EXCEPTION(EX_StackUnder);
        goto invalid_operand;
    } else if (st0_tag == TAG_Special) {
        st0_tag = FPU_Special(st0_ptr);
        if ((st0_tag == TW_Infinity) || (st0_tag == TW_NaN)) {
            EXCEPTION(EX_Invalid);
            goto invalid_operand;
        }
    }

    reg_copy(st0_ptr, &t);
    precision_loss = FPU_round_to_int(&t, st0_tag);
    if (t.sigh ||
        ((t.sigl & 0x80000000) &&
         !((t.sigl == 0x80000000) && signnegative(&t)))) {
        EXCEPTION(EX_Invalid);
        /* This is a special case: see sec 16.2.5.1 of the 80486 book */
          invalid_operand:
        if (control_word & EX_Invalid) {
            /* Produce something like QNaN "indefinite" */
            t.sigl = 0x80000000;
        } else
            return 0;
    } else {
        if (precision_loss)
            set_precision_flag(precision_loss);
        if (signnegative(&t))
            t.sigl = -(long)t.sigl;
    }

    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_WRITE, d, 4);
    FPU_put_user(t.sigl, (unsigned long __user *)d);
    RE_ENTRANT_CHECK_ON;

    return 1;
}

/* Put a short into user memory */
int FPU_store_int16(FPU_REG *st0_ptr, u_char st0_tag, short __user *d)
{
    FPU_REG t;
    int precision_loss;

    if (st0_tag == TAG_Empty) {
        /* Empty register (stack underflow) */
        EXCEPTION(EX_StackUnder);
        goto invalid_operand;
    } else if (st0_tag == TAG_Special) {
        st0_tag = FPU_Special(st0_ptr);
        if ((st0_tag == TW_Infinity) || (st0_tag == TW_NaN)) {
            EXCEPTION(EX_Invalid);
            goto invalid_operand;
        }
    }

    reg_copy(st0_ptr, &t);
    precision_loss = FPU_round_to_int(&t, st0_tag);
    if (t.sigh ||
        ((t.sigl & 0xffff8000) &&
         !((t.sigl == 0x8000) && signnegative(&t)))) {
        EXCEPTION(EX_Invalid);
        /* This is a special case: see sec 16.2.5.1 of the 80486 book */
          invalid_operand:
        if (control_word & EX_Invalid) {
            /* Produce something like QNaN "indefinite" */
            t.sigl = 0x8000;
        } else
            return 0;
    } else {
        if (precision_loss)
            set_precision_flag(precision_loss);
        if (signnegative(&t))
            t.sigl = -t.sigl;
    }

    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_WRITE, d, 2);
    FPU_put_user((short)t.sigl, d);
    RE_ENTRANT_CHECK_ON;

    return 1;
}

/* Put a packed bcd array into user memory */
int FPU_store_bcd(FPU_REG *st0_ptr, u_char st0_tag, u_char __user *d)
{
    FPU_REG t;
    unsigned long long ll;
    u_char b;
    int i, precision_loss;
    u_char sign = (getsign(st0_ptr) == SIGN_NEG) ? 0x80 : 0;

    if (st0_tag == TAG_Empty) {
        /* Empty register (stack underflow) */
        EXCEPTION(EX_StackUnder);
        goto invalid_operand;
    } else if (st0_tag == TAG_Special) {
        st0_tag = FPU_Special(st0_ptr);
        if ((st0_tag == TW_Infinity) || (st0_tag == TW_NaN)) {
            EXCEPTION(EX_Invalid);
            goto invalid_operand;
        }
    }

    reg_copy(st0_ptr, &t);
    precision_loss = FPU_round_to_int(&t, st0_tag);
    ll = significand(&t);

    /* Check for overflow, by comparing with 999999999999999999 decimal. */
    if ((t.sigh > 0x0de0b6b3) ||
        ((t.sigh == 0x0de0b6b3) && (t.sigl > 0xa763ffff))) {
        EXCEPTION(EX_Invalid);
        /* This is a special case: see sec 16.2.5.1 of the 80486 book */
          invalid_operand:
        if (control_word & CW_Invalid) {
            /* Produce the QNaN "indefinite" */
            RE_ENTRANT_CHECK_OFF;
            FPU_access_ok(VERIFY_WRITE, d, 10);
            for (i = 0; i < 7; i++)
                FPU_put_user(0, d + i); /* These bytes "undefined" */
            FPU_put_user(0xc0, d + 7);  /* This byte "undefined" */
            FPU_put_user(0xff, d + 8);
            FPU_put_user(0xff, d + 9);
            RE_ENTRANT_CHECK_ON;
            return 1;
        } else
            return 0;
    } else if (precision_loss) {
        /* Precision loss doesn't stop the data transfer */
        set_precision_flag(precision_loss);
    }

    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_WRITE, d, 10);
    RE_ENTRANT_CHECK_ON;
    for (i = 0; i < 9; i++) {
        b = FPU_div_small(&ll, 10);
        b |= (FPU_div_small(&ll, 10)) << 4;
        RE_ENTRANT_CHECK_OFF;
        FPU_put_user(b, d + i);
        RE_ENTRANT_CHECK_ON;
    }
    RE_ENTRANT_CHECK_OFF;
    FPU_put_user(sign, d + 9);
    RE_ENTRANT_CHECK_ON;

    return 1;
}

/*===========================================================================*/

/* r gets mangled such that sig is int, sign: 
   it is NOT normalized */
/* The return value (in eax) is zero if the result is exact,
   if bits are changed due to rounding, truncation, etc, then
   a non-zero value is returned */
/* Overflow is signalled by a non-zero return value (in eax).
   In the case of overflow, the returned significand always has the
   largest possible value */
int FPU_round_to_int(FPU_REG *r, u_char tag)
{
    u_char very_big;
    unsigned eax;

    if (tag == TAG_Zero) {
        /* Make sure that zero is returned */
        significand(r) = 0;
        return 0;   /* o.k. */
    }

    if (exponent(r) > 63) {
        r->sigl = r->sigh = ~0; /* The largest representable number */
        return 1;   /* overflow */
    }

    eax = FPU_shrxs(&r->sigl, 63 - exponent(r));
    very_big = !(~(r->sigh) | ~(r->sigl));  /* test for 0xfff...fff */
#define half_or_more    (eax & 0x80000000)
#define frac_part   (eax)
#define more_than_half  ((eax & 0x80000001) == 0x80000001)
    switch (control_word & CW_RC) {
    case RC_RND:
        if (more_than_half  /* nearest */
            || (half_or_more && (r->sigl & 1))) {   /* odd -> even */
            if (very_big)
                return 1;   /* overflow */
            significand(r)++;
            return PRECISION_LOST_UP;
        }
        break;
    case RC_DOWN:
        if (frac_part && getsign(r)) {
            if (very_big)
                return 1;   /* overflow */
            significand(r)++;
            return PRECISION_LOST_UP;
        }
        break;
    case RC_UP:
        if (frac_part && !getsign(r)) {
            if (very_big)
                return 1;   /* overflow */
            significand(r)++;
            return PRECISION_LOST_UP;
        }
        break;
    case RC_CHOP:
        break;
    }

    return eax ? PRECISION_LOST_DOWN : 0;

}

/*===========================================================================*/

u_char __user *fldenv(fpu_addr_modes addr_modes, u_char __user *s)
{
    unsigned short tag_word = 0;
    u_char tag;
    int i;

    if ((addr_modes.default_mode == VM86) ||
        ((addr_modes.default_mode == PM16)
         ^ (addr_modes.override.operand_size == OP_SIZE_PREFIX))) {
        RE_ENTRANT_CHECK_OFF;
        FPU_access_ok(VERIFY_READ, s, 0x0e);
        FPU_get_user(control_word, (unsigned short __user *)s);
        FPU_get_user(partial_status, (unsigned short __user *)(s + 2));
        FPU_get_user(tag_word, (unsigned short __user *)(s + 4));
        FPU_get_user(instruction_address.offset,
                 (unsigned short __user *)(s + 6));
        FPU_get_user(instruction_address.selector,
                 (unsigned short __user *)(s + 8));
        FPU_get_user(operand_address.offset,
                 (unsigned short __user *)(s + 0x0a));
        FPU_get_user(operand_address.selector,
                 (unsigned short __user *)(s + 0x0c));
        RE_ENTRANT_CHECK_ON;
        s += 0x0e;
        if (addr_modes.default_mode == VM86) {
            instruction_address.offset
                += (instruction_address.selector & 0xf000) << 4;
            operand_address.offset +=
                (operand_address.selector & 0xf000) << 4;
        }
    } else {
        RE_ENTRANT_CHECK_OFF;
        FPU_access_ok(VERIFY_READ, s, 0x1c);
        FPU_get_user(control_word, (unsigned short __user *)s);
        FPU_get_user(partial_status, (unsigned short __user *)(s + 4));
        FPU_get_user(tag_word, (unsigned short __user *)(s + 8));
        FPU_get_user(instruction_address.offset,
                 (unsigned long __user *)(s + 0x0c));
        FPU_get_user(instruction_address.selector,
                 (unsigned short __user *)(s + 0x10));
        FPU_get_user(instruction_address.opcode,
                 (unsigned short __user *)(s + 0x12));
        FPU_get_user(operand_address.offset,
                 (unsigned long __user *)(s + 0x14));
        FPU_get_user(operand_address.selector,
                 (unsigned long __user *)(s + 0x18));
        RE_ENTRANT_CHECK_ON;
        s += 0x1c;
    }

#ifdef PECULIAR_486
    control_word &= ~0xe080;
#endif /* PECULIAR_486 */

    top = (partial_status >> SW_Top_Shift) & 7;

    if (partial_status & ~control_word & CW_Exceptions)
        partial_status |= (SW_Summary | SW_Backward);
    else
        partial_status &= ~(SW_Summary | SW_Backward);

    for (i = 0; i < 8; i++) {
        tag = tag_word & 3;
        tag_word >>= 2;

        if (tag == TAG_Empty)
            /* New tag is empty.  Accept it */
            FPU_settag(i, TAG_Empty);
        else if (FPU_gettag(i) == TAG_Empty) {
            /* Old tag is empty and new tag is not empty.  New tag is determined
               by old reg contents */
            if (exponent(&fpu_register(i)) == -EXTENDED_Ebias) {
                if (!
                    (fpu_register(i).sigl | fpu_register(i).
                     sigh))
                    FPU_settag(i, TAG_Zero);
                else
                    FPU_settag(i, TAG_Special);
            } else if (exponent(&fpu_register(i)) ==
                   0x7fff - EXTENDED_Ebias) {
                FPU_settag(i, TAG_Special);
            } else if (fpu_register(i).sigh & 0x80000000)
                FPU_settag(i, TAG_Valid);
            else
                FPU_settag(i, TAG_Special); /* An Un-normal */
        }
        /* Else old tag is not empty and new tag is not empty.  Old tag
           remains correct */
    }

    return s;
}

void frstor(fpu_addr_modes addr_modes, u_char __user *data_address)
{
    int i, regnr;
    u_char __user *s = fldenv(addr_modes, data_address);
    int offset = (top & 7) * 10, other = 80 - offset;

    /* Copy all registers in stack order. */
    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_READ, s, 80);
    __copy_from_user(register_base + offset, s, other);
    if (offset)
        __copy_from_user(register_base, s + other, offset);
    RE_ENTRANT_CHECK_ON;

    for (i = 0; i < 8; i++) {
        regnr = (i + top) & 7;
        if (FPU_gettag(regnr) != TAG_Empty)
            /* The loaded data over-rides all other cases. */
            FPU_settag(regnr, FPU_tagof(&st(i)));
    }

}

u_char __user *fstenv(fpu_addr_modes addr_modes, u_char __user *d)
{
    if ((addr_modes.default_mode == VM86) ||
        ((addr_modes.default_mode == PM16)
         ^ (addr_modes.override.operand_size == OP_SIZE_PREFIX))) {
        RE_ENTRANT_CHECK_OFF;
        FPU_access_ok(VERIFY_WRITE, d, 14);
#ifdef PECULIAR_486
        FPU_put_user(control_word & ~0xe080, (unsigned long __user *)d);
#else
        FPU_put_user(control_word, (unsigned short __user *)d);
#endif /* PECULIAR_486 */
        FPU_put_user(status_word(), (unsigned short __user *)(d + 2));
        FPU_put_user(fpu_tag_word, (unsigned short __user *)(d + 4));
        FPU_put_user(instruction_address.offset,
                 (unsigned short __user *)(d + 6));
        FPU_put_user(operand_address.offset,
                 (unsigned short __user *)(d + 0x0a));
        if (addr_modes.default_mode == VM86) {
            FPU_put_user((instruction_address.
                      offset & 0xf0000) >> 4,
                     (unsigned short __user *)(d + 8));
            FPU_put_user((operand_address.offset & 0xf0000) >> 4,
                     (unsigned short __user *)(d + 0x0c));
        } else {
            FPU_put_user(instruction_address.selector,
                     (unsigned short __user *)(d + 8));
            FPU_put_user(operand_address.selector,
                     (unsigned short __user *)(d + 0x0c));
        }
        RE_ENTRANT_CHECK_ON;
        d += 0x0e;
    } else {
        RE_ENTRANT_CHECK_OFF;
        FPU_access_ok(VERIFY_WRITE, d, 7 * 4);
#ifdef PECULIAR_486
        control_word &= ~0xe080;
        /* An 80486 sets nearly all of the reserved bits to 1. */
        control_word |= 0xffff0040;
        partial_status = status_word() | 0xffff0000;
        fpu_tag_word |= 0xffff0000;
        I387->soft.fcs &= ~0xf8000000;
        I387->soft.fos |= 0xffff0000;
#endif /* PECULIAR_486 */
        if (__copy_to_user(d, &control_word, 7 * 4))
            FPU_abort;
        RE_ENTRANT_CHECK_ON;
        d += 0x1c;
    }

    control_word |= CW_Exceptions;
    partial_status &= ~(SW_Summary | SW_Backward);

    return d;
}

void fsave(fpu_addr_modes addr_modes, u_char __user *data_address)
{
    u_char __user *d;
    int offset = (top & 7) * 10, other = 80 - offset;

    d = fstenv(addr_modes, data_address);

    RE_ENTRANT_CHECK_OFF;
    FPU_access_ok(VERIFY_WRITE, d, 80);

    /* Copy all registers in stack order. */
    if (__copy_to_user(d, register_base + offset, other))
        FPU_abort;
    if (offset)
        if (__copy_to_user(d + other, register_base, offset))
            FPU_abort;
    RE_ENTRANT_CHECK_ON;

    finit();
}

/*===========================================================================*/