Linux-2.6.12-rc2

[linux-2.6/kvm.git] / arch / arm / vfp / vfpsingle.c

/*
 *  linux/arch/arm/vfp/vfpsingle.c
 *
 * This code is derived in part from John R. Housers softfloat library, which
 * carries the following notice:
 *
 * ===========================================================================
 * This C source file is part of the SoftFloat IEC/IEEE Floating-point
 * Arithmetic Package, Release 2.
 *
 * Written by John R. Hauser.  This work was made possible in part by the
 * International Computer Science Institute, located at Suite 600, 1947 Center
 * Street, Berkeley, California 94704.  Funding was partially provided by the
 * National Science Foundation under grant MIP-9311980.  The original version
 * of this code was written as part of a project to build a fixed-point vector
 * processor in collaboration with the University of California at Berkeley,
 * overseen by Profs. Nelson Morgan and John Wawrzynek.  More information
 * is available through the web page `http://HTTP.CS.Berkeley.EDU/~jhauser/
 * arithmetic/softfloat.html'.
 *
 * THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE.  Although reasonable effort
 * has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT
 * TIMES RESULT IN INCORRECT BEHAVIOR.  USE OF THIS SOFTWARE IS RESTRICTED TO
 * PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY
 * AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE.
 *
 * Derivative works are acceptable, even for commercial purposes, so long as
 * (1) they include prominent notice that the work is derivative, and (2) they
 * include prominent notice akin to these three paragraphs for those parts of
 * this code that are retained.
 * ===========================================================================
 */
#include <linux/kernel.h>
#include <linux/bitops.h>
#include <asm/ptrace.h>
#include <asm/vfp.h>

#include "vfpinstr.h"
#include "vfp.h"

static struct vfp_single vfp_single_default_qnan = {
        .exponent       = 255,
        .sign           = 0,
        .significand    = VFP_SINGLE_SIGNIFICAND_QNAN,
};

static void vfp_single_dump(const char *str, struct vfp_single *s)
{
        pr_debug("VFP: %s: sign=%d exponent=%d significand=%08x\n",
                 str, s->sign != 0, s->exponent, s->significand);
}

static void vfp_single_normalise_denormal(struct vfp_single *vs)
{
        int bits = 31 - fls(vs->significand);

        vfp_single_dump("normalise_denormal: in", vs);

        if (bits) {
                vs->exponent -= bits - 1;
                vs->significand <<= bits;
        }

        vfp_single_dump("normalise_denormal: out", vs);
}

#ifndef DEBUG
#define vfp_single_normaliseround(sd,vsd,fpscr,except,func) __vfp_single_normaliseround(sd,vsd,fpscr,except)
u32 __vfp_single_normaliseround(int sd, struct vfp_single *vs, u32 fpscr, u32 exceptions)
#else
u32 vfp_single_normaliseround(int sd, struct vfp_single *vs, u32 fpscr, u32 exceptions, const char *func)
#endif
{
        u32 significand, incr, rmode;
        int exponent, shift, underflow;

        vfp_single_dump("pack: in", vs);

        /*
         * Infinities and NaNs are a special case.
         */
        if (vs->exponent == 255 && (vs->significand == 0 || exceptions))
                goto pack;

        /*
         * Special-case zero.
         */
        if (vs->significand == 0) {
                vs->exponent = 0;
                goto pack;
        }

        exponent = vs->exponent;
        significand = vs->significand;

        /*
         * Normalise first.  Note that we shift the significand up to
         * bit 31, so we have VFP_SINGLE_LOW_BITS + 1 below the least
         * significant bit.
         */
        shift = 32 - fls(significand);
        if (shift < 32 && shift) {
                exponent -= shift;
                significand <<= shift;
        }

#ifdef DEBUG
        vs->exponent = exponent;
        vs->significand = significand;
        vfp_single_dump("pack: normalised", vs);
#endif

        /*
         * Tiny number?
         */
        underflow = exponent < 0;
        if (underflow) {
                significand = vfp_shiftright32jamming(significand, -exponent);
                exponent = 0;
#ifdef DEBUG
                vs->exponent = exponent;
                vs->significand = significand;
                vfp_single_dump("pack: tiny number", vs);
#endif
                if (!(significand & ((1 << (VFP_SINGLE_LOW_BITS + 1)) - 1)))
                        underflow = 0;
        }

        /*
         * Select rounding increment.
         */
        incr = 0;
        rmode = fpscr & FPSCR_RMODE_MASK;

        if (rmode == FPSCR_ROUND_NEAREST) {
                incr = 1 << VFP_SINGLE_LOW_BITS;
                if ((significand & (1 << (VFP_SINGLE_LOW_BITS + 1))) == 0)
                        incr -= 1;
        } else if (rmode == FPSCR_ROUND_TOZERO) {
                incr = 0;
        } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vs->sign != 0))
                incr = (1 << (VFP_SINGLE_LOW_BITS + 1)) - 1;

        pr_debug("VFP: rounding increment = 0x%08x\n", incr);

        /*
         * Is our rounding going to overflow?
         */
        if ((significand + incr) < significand) {
                exponent += 1;
                significand = (significand >> 1) | (significand & 1);
                incr >>= 1;
#ifdef DEBUG
                vs->exponent = exponent;
                vs->significand = significand;
                vfp_single_dump("pack: overflow", vs);
#endif
        }

        /*
         * If any of the low bits (which will be shifted out of the
         * number) are non-zero, the result is inexact.
         */
        if (significand & ((1 << (VFP_SINGLE_LOW_BITS + 1)) - 1))
                exceptions |= FPSCR_IXC;

        /*
         * Do our rounding.
         */
        significand += incr;

        /*
         * Infinity?
         */
        if (exponent >= 254) {
                exceptions |= FPSCR_OFC | FPSCR_IXC;
                if (incr == 0) {
                        vs->exponent = 253;
                        vs->significand = 0x7fffffff;
                } else {
                        vs->exponent = 255;             /* infinity */
                        vs->significand = 0;
                }
        } else {
                if (significand >> (VFP_SINGLE_LOW_BITS + 1) == 0)
                        exponent = 0;
                if (exponent || significand > 0x80000000)
                        underflow = 0;
                if (underflow)
                        exceptions |= FPSCR_UFC;
                vs->exponent = exponent;
                vs->significand = significand >> 1;
        }

 pack:
        vfp_single_dump("pack: final", vs);
        {
                s32 d = vfp_single_pack(vs);
                pr_debug("VFP: %s: d(s%d)=%08x exceptions=%08x\n", func,
                         sd, d, exceptions);
                vfp_put_float(sd, d);
        }

        return exceptions & ~VFP_NAN_FLAG;
}

/*
 * Propagate the NaN, setting exceptions if it is signalling.
 * 'n' is always a NaN.  'm' may be a number, NaN or infinity.
 */
static u32
vfp_propagate_nan(struct vfp_single *vsd, struct vfp_single *vsn,
                  struct vfp_single *vsm, u32 fpscr)
{
        struct vfp_single *nan;
        int tn, tm = 0;

        tn = vfp_single_type(vsn);

        if (vsm)
                tm = vfp_single_type(vsm);

        if (fpscr & FPSCR_DEFAULT_NAN)
                /*
                 * Default NaN mode - always returns a quiet NaN
                 */
                nan = &vfp_single_default_qnan;
        else {
                /*
                 * Contemporary mode - select the first signalling
                 * NAN, or if neither are signalling, the first
                 * quiet NAN.
                 */
                if (tn == VFP_SNAN || (tm != VFP_SNAN && tn == VFP_QNAN))
                        nan = vsn;
                else
                        nan = vsm;
                /*
                 * Make the NaN quiet.
                 */
                nan->significand |= VFP_SINGLE_SIGNIFICAND_QNAN;
        }

        *vsd = *nan;

        /*
         * If one was a signalling NAN, raise invalid operation.
         */
        return tn == VFP_SNAN || tm == VFP_SNAN ? FPSCR_IOC : VFP_NAN_FLAG;
}


/*
 * Extended operations
 */
static u32 vfp_single_fabs(int sd, int unused, s32 m, u32 fpscr)
{
        vfp_put_float(sd, vfp_single_packed_abs(m));
        return 0;
}

static u32 vfp_single_fcpy(int sd, int unused, s32 m, u32 fpscr)
{
        vfp_put_float(sd, m);
        return 0;
}

static u32 vfp_single_fneg(int sd, int unused, s32 m, u32 fpscr)
{
        vfp_put_float(sd, vfp_single_packed_negate(m));
        return 0;
}

static const u16 sqrt_oddadjust[] = {
        0x0004, 0x0022, 0x005d, 0x00b1, 0x011d, 0x019f, 0x0236, 0x02e0,
        0x039c, 0x0468, 0x0545, 0x0631, 0x072b, 0x0832, 0x0946, 0x0a67
};

static const u16 sqrt_evenadjust[] = {
        0x0a2d, 0x08af, 0x075a, 0x0629, 0x051a, 0x0429, 0x0356, 0x029e,
        0x0200, 0x0179, 0x0109, 0x00af, 0x0068, 0x0034, 0x0012, 0x0002
};

u32 vfp_estimate_sqrt_significand(u32 exponent, u32 significand)
{
        int index;
        u32 z, a;

        if ((significand & 0xc0000000) != 0x40000000) {
                printk(KERN_WARNING "VFP: estimate_sqrt: invalid significand\n");
        }

        a = significand << 1;
        index = (a >> 27) & 15;
        if (exponent & 1) {
                z = 0x4000 + (a >> 17) - sqrt_oddadjust[index];
                z = ((a / z) << 14) + (z << 15);
                a >>= 1;
        } else {
                z = 0x8000 + (a >> 17) - sqrt_evenadjust[index];
                z = a / z + z;
                z = (z >= 0x20000) ? 0xffff8000 : (z << 15);
                if (z <= a)
                        return (s32)a >> 1;
        }
        return (u32)(((u64)a << 31) / z) + (z >> 1);
}

static u32 vfp_single_fsqrt(int sd, int unused, s32 m, u32 fpscr)
{
        struct vfp_single vsm, vsd;
        int ret, tm;

        vfp_single_unpack(&vsm, m);
        tm = vfp_single_type(&vsm);
        if (tm & (VFP_NAN|VFP_INFINITY)) {
                struct vfp_single *vsp = &vsd;

                if (tm & VFP_NAN)
                        ret = vfp_propagate_nan(vsp, &vsm, NULL, fpscr);
                else if (vsm.sign == 0) {
 sqrt_copy:
                        vsp = &vsm;
                        ret = 0;
                } else {
 sqrt_invalid:
                        vsp = &vfp_single_default_qnan;
                        ret = FPSCR_IOC;
                }
                vfp_put_float(sd, vfp_single_pack(vsp));
                return ret;
        }

        /*
         * sqrt(+/- 0) == +/- 0
         */
        if (tm & VFP_ZERO)
                goto sqrt_copy;

        /*
         * Normalise a denormalised number
         */
        if (tm & VFP_DENORMAL)
                vfp_single_normalise_denormal(&vsm);

        /*
         * sqrt(<0) = invalid
         */
        if (vsm.sign)
                goto sqrt_invalid;

        vfp_single_dump("sqrt", &vsm);

        /*
         * Estimate the square root.
         */
        vsd.sign = 0;
        vsd.exponent = ((vsm.exponent - 127) >> 1) + 127;
        vsd.significand = vfp_estimate_sqrt_significand(vsm.exponent, vsm.significand) + 2;

        vfp_single_dump("sqrt estimate", &vsd);

        /*
         * And now adjust.
         */
        if ((vsd.significand & VFP_SINGLE_LOW_BITS_MASK) <= 5) {
                if (vsd.significand < 2) {
                        vsd.significand = 0xffffffff;
                } else {
                        u64 term;
                        s64 rem;
                        vsm.significand <<= !(vsm.exponent & 1);
                        term = (u64)vsd.significand * vsd.significand;
                        rem = ((u64)vsm.significand << 32) - term;

                        pr_debug("VFP: term=%016llx rem=%016llx\n", term, rem);

                        while (rem < 0) {
                                vsd.significand -= 1;
                                rem += ((u64)vsd.significand << 1) | 1;
                        }
                        vsd.significand |= rem != 0;
                }
        }
        vsd.significand = vfp_shiftright32jamming(vsd.significand, 1);

        return vfp_single_normaliseround(sd, &vsd, fpscr, 0, "fsqrt");
}

/*
 * Equal        := ZC
 * Less than    := N
 * Greater than := C
 * Unordered    := CV
 */
static u32 vfp_compare(int sd, int signal_on_qnan, s32 m, u32 fpscr)
{
        s32 d;
        u32 ret = 0;

        d = vfp_get_float(sd);
        if (vfp_single_packed_exponent(m) == 255 && vfp_single_packed_mantissa(m)) {
                ret |= FPSCR_C | FPSCR_V;
                if (signal_on_qnan || !(vfp_single_packed_mantissa(m) & (1 << (VFP_SINGLE_MANTISSA_BITS - 1))))
                        /*
                         * Signalling NaN, or signalling on quiet NaN
                         */
                        ret |= FPSCR_IOC;
        }

        if (vfp_single_packed_exponent(d) == 255 && vfp_single_packed_mantissa(d)) {
                ret |= FPSCR_C | FPSCR_V;
                if (signal_on_qnan || !(vfp_single_packed_mantissa(d) & (1 << (VFP_SINGLE_MANTISSA_BITS - 1))))
                        /*
                         * Signalling NaN, or signalling on quiet NaN
                         */
                        ret |= FPSCR_IOC;
        }

        if (ret == 0) {
                if (d == m || vfp_single_packed_abs(d | m) == 0) {
                        /*
                         * equal
                         */
                        ret |= FPSCR_Z | FPSCR_C;
                } else if (vfp_single_packed_sign(d ^ m)) {
                        /*
                         * different signs
                         */
                        if (vfp_single_packed_sign(d))
                                /*
                                 * d is negative, so d < m
                                 */
                                ret |= FPSCR_N;
                        else
                                /*
                                 * d is positive, so d > m
                                 */
                                ret |= FPSCR_C;
                } else if ((vfp_single_packed_sign(d) != 0) ^ (d < m)) {
                        /*
                         * d < m
                         */
                        ret |= FPSCR_N;
                } else if ((vfp_single_packed_sign(d) != 0) ^ (d > m)) {
                        /*
                         * d > m
                         */
                        ret |= FPSCR_C;
                }
        }
        return ret;
}

static u32 vfp_single_fcmp(int sd, int unused, s32 m, u32 fpscr)
{
        return vfp_compare(sd, 0, m, fpscr);
}

static u32 vfp_single_fcmpe(int sd, int unused, s32 m, u32 fpscr)
{
        return vfp_compare(sd, 1, m, fpscr);
}

static u32 vfp_single_fcmpz(int sd, int unused, s32 m, u32 fpscr)
{
        return vfp_compare(sd, 0, 0, fpscr);
}

static u32 vfp_single_fcmpez(int sd, int unused, s32 m, u32 fpscr)
{
        return vfp_compare(sd, 1, 0, fpscr);
}

static u32 vfp_single_fcvtd(int dd, int unused, s32 m, u32 fpscr)
{
        struct vfp_single vsm;
        struct vfp_double vdd;
        int tm;
        u32 exceptions = 0;

        vfp_single_unpack(&vsm, m);

        tm = vfp_single_type(&vsm);

        /*
         * If we have a signalling NaN, signal invalid operation.
         */
        if (tm == VFP_SNAN)
                exceptions = FPSCR_IOC;

        if (tm & VFP_DENORMAL)
                vfp_single_normalise_denormal(&vsm);

        vdd.sign = vsm.sign;
        vdd.significand = (u64)vsm.significand << 32;

        /*
         * If we have an infinity or NaN, the exponent must be 2047.
         */
        if (tm & (VFP_INFINITY|VFP_NAN)) {
                vdd.exponent = 2047;
                if (tm & VFP_NAN)
                        vdd.significand |= VFP_DOUBLE_SIGNIFICAND_QNAN;
                goto pack_nan;
        } else if (tm & VFP_ZERO)
                vdd.exponent = 0;
        else
                vdd.exponent = vsm.exponent + (1023 - 127);

        /*
         * Technically, if bit 0 of dd is set, this is an invalid
         * instruction.  However, we ignore this for efficiency.
         */
        return vfp_double_normaliseround(dd, &vdd, fpscr, exceptions, "fcvtd");

 pack_nan:
        vfp_put_double(dd, vfp_double_pack(&vdd));
        return exceptions;
}

static u32 vfp_single_fuito(int sd, int unused, s32 m, u32 fpscr)
{
        struct vfp_single vs;

        vs.sign = 0;
        vs.exponent = 127 + 31 - 1;
        vs.significand = (u32)m;

        return vfp_single_normaliseround(sd, &vs, fpscr, 0, "fuito");
}

static u32 vfp_single_fsito(int sd, int unused, s32 m, u32 fpscr)
{
        struct vfp_single vs;

        vs.sign = (m & 0x80000000) >> 16;
        vs.exponent = 127 + 31 - 1;
        vs.significand = vs.sign ? -m : m;

        return vfp_single_normaliseround(sd, &vs, fpscr, 0, "fsito");
}

static u32 vfp_single_ftoui(int sd, int unused, s32 m, u32 fpscr)
{
        struct vfp_single vsm;
        u32 d, exceptions = 0;
        int rmode = fpscr & FPSCR_RMODE_MASK;
        int tm;

        vfp_single_unpack(&vsm, m);
        vfp_single_dump("VSM", &vsm);

        /*
         * Do we have a denormalised number?
         */
        tm = vfp_single_type(&vsm);
        if (tm & VFP_DENORMAL)
                exceptions |= FPSCR_IDC;

        if (tm & VFP_NAN)
                vsm.sign = 0;

        if (vsm.exponent >= 127 + 32) {
                d = vsm.sign ? 0 : 0xffffffff;
                exceptions = FPSCR_IOC;
        } else if (vsm.exponent >= 127 - 1) {
                int shift = 127 + 31 - vsm.exponent;
                u32 rem, incr = 0;

                /*
                 * 2^0 <= m < 2^32-2^8
                 */
                d = (vsm.significand << 1) >> shift;
                rem = vsm.significand << (33 - shift);

                if (rmode == FPSCR_ROUND_NEAREST) {
                        incr = 0x80000000;
                        if ((d & 1) == 0)
                                incr -= 1;
                } else if (rmode == FPSCR_ROUND_TOZERO) {
                        incr = 0;
                } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vsm.sign != 0)) {
                        incr = ~0;
                }

                if ((rem + incr) < rem) {
                        if (d < 0xffffffff)
                                d += 1;
                        else
                                exceptions |= FPSCR_IOC;
                }

                if (d && vsm.sign) {
                        d = 0;
                        exceptions |= FPSCR_IOC;
                } else if (rem)
                        exceptions |= FPSCR_IXC;
        } else {
                d = 0;
                if (vsm.exponent | vsm.significand) {
                        exceptions |= FPSCR_IXC;
                        if (rmode == FPSCR_ROUND_PLUSINF && vsm.sign == 0)
                                d = 1;
                        else if (rmode == FPSCR_ROUND_MINUSINF && vsm.sign) {
                                d = 0;
                                exceptions |= FPSCR_IOC;
                        }
                }
        }

        pr_debug("VFP: ftoui: d(s%d)=%08x exceptions=%08x\n", sd, d, exceptions);

        vfp_put_float(sd, d);

        return exceptions;
}

static u32 vfp_single_ftouiz(int sd, int unused, s32 m, u32 fpscr)
{
        return vfp_single_ftoui(sd, unused, m, FPSCR_ROUND_TOZERO);
}

static u32 vfp_single_ftosi(int sd, int unused, s32 m, u32 fpscr)
{
        struct vfp_single vsm;
        u32 d, exceptions = 0;
        int rmode = fpscr & FPSCR_RMODE_MASK;

        vfp_single_unpack(&vsm, m);
        vfp_single_dump("VSM", &vsm);

        /*
         * Do we have a denormalised number?
         */
        if (vfp_single_type(&vsm) & VFP_DENORMAL)
                exceptions |= FPSCR_IDC;

        if (vsm.exponent >= 127 + 32) {
                /*
                 * m >= 2^31-2^7: invalid
                 */
                d = 0x7fffffff;
                if (vsm.sign)
                        d = ~d;
                exceptions |= FPSCR_IOC;
        } else if (vsm.exponent >= 127 - 1) {
                int shift = 127 + 31 - vsm.exponent;
                u32 rem, incr = 0;

                /* 2^0 <= m <= 2^31-2^7 */
                d = (vsm.significand << 1) >> shift;
                rem = vsm.significand << (33 - shift);

                if (rmode == FPSCR_ROUND_NEAREST) {
                        incr = 0x80000000;
                        if ((d & 1) == 0)
                                incr -= 1;
                } else if (rmode == FPSCR_ROUND_TOZERO) {
                        incr = 0;
                } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vsm.sign != 0)) {
                        incr = ~0;
                }

                if ((rem + incr) < rem && d < 0xffffffff)
                        d += 1;
                if (d > 0x7fffffff + (vsm.sign != 0)) {
                        d = 0x7fffffff + (vsm.sign != 0);
                        exceptions |= FPSCR_IOC;
                } else if (rem)
                        exceptions |= FPSCR_IXC;

                if (vsm.sign)
                        d = -d;
        } else {
                d = 0;
                if (vsm.exponent | vsm.significand) {
                        exceptions |= FPSCR_IXC;
                        if (rmode == FPSCR_ROUND_PLUSINF && vsm.sign == 0)
                                d = 1;
                        else if (rmode == FPSCR_ROUND_MINUSINF && vsm.sign)
                                d = -1;
                }
        }

        pr_debug("VFP: ftosi: d(s%d)=%08x exceptions=%08x\n", sd, d, exceptions);

        vfp_put_float(sd, (s32)d);

        return exceptions;
}

static u32 vfp_single_ftosiz(int sd, int unused, s32 m, u32 fpscr)
{
        return vfp_single_ftosi(sd, unused, m, FPSCR_ROUND_TOZERO);
}

static u32 (* const fop_extfns[32])(int sd, int unused, s32 m, u32 fpscr) = {
        [FEXT_TO_IDX(FEXT_FCPY)]        = vfp_single_fcpy,
        [FEXT_TO_IDX(FEXT_FABS)]        = vfp_single_fabs,
        [FEXT_TO_IDX(FEXT_FNEG)]        = vfp_single_fneg,
        [FEXT_TO_IDX(FEXT_FSQRT)]       = vfp_single_fsqrt,
        [FEXT_TO_IDX(FEXT_FCMP)]        = vfp_single_fcmp,
        [FEXT_TO_IDX(FEXT_FCMPE)]       = vfp_single_fcmpe,
        [FEXT_TO_IDX(FEXT_FCMPZ)]       = vfp_single_fcmpz,
        [FEXT_TO_IDX(FEXT_FCMPEZ)]      = vfp_single_fcmpez,
        [FEXT_TO_IDX(FEXT_FCVT)]        = vfp_single_fcvtd,
        [FEXT_TO_IDX(FEXT_FUITO)]       = vfp_single_fuito,
        [FEXT_TO_IDX(FEXT_FSITO)]       = vfp_single_fsito,
        [FEXT_TO_IDX(FEXT_FTOUI)]       = vfp_single_ftoui,
        [FEXT_TO_IDX(FEXT_FTOUIZ)]      = vfp_single_ftouiz,
        [FEXT_TO_IDX(FEXT_FTOSI)]       = vfp_single_ftosi,
        [FEXT_TO_IDX(FEXT_FTOSIZ)]      = vfp_single_ftosiz,
};





static u32
vfp_single_fadd_nonnumber(struct vfp_single *vsd, struct vfp_single *vsn,
                          struct vfp_single *vsm, u32 fpscr)
{
        struct vfp_single *vsp;
        u32 exceptions = 0;
        int tn, tm;

        tn = vfp_single_type(vsn);
        tm = vfp_single_type(vsm);

        if (tn & tm & VFP_INFINITY) {
                /*
                 * Two infinities.  Are they different signs?
                 */
                if (vsn->sign ^ vsm->sign) {
                        /*
                         * different signs -> invalid
                         */
                        exceptions = FPSCR_IOC;
                        vsp = &vfp_single_default_qnan;
                } else {
                        /*
                         * same signs -> valid
                         */
                        vsp = vsn;
                }
        } else if (tn & VFP_INFINITY && tm & VFP_NUMBER) {
                /*
                 * One infinity and one number -> infinity
                 */
                vsp = vsn;
        } else {
                /*
                 * 'n' is a NaN of some type
                 */
                return vfp_propagate_nan(vsd, vsn, vsm, fpscr);
        }
        *vsd = *vsp;
        return exceptions;
}

static u32
vfp_single_add(struct vfp_single *vsd, struct vfp_single *vsn,
               struct vfp_single *vsm, u32 fpscr)
{
        u32 exp_diff, m_sig;

        if (vsn->significand & 0x80000000 ||
            vsm->significand & 0x80000000) {
                pr_info("VFP: bad FP values in %s\n", __func__);
                vfp_single_dump("VSN", vsn);
                vfp_single_dump("VSM", vsm);
        }

        /*
         * Ensure that 'n' is the largest magnitude number.  Note that
         * if 'n' and 'm' have equal exponents, we do not swap them.
         * This ensures that NaN propagation works correctly.
         */
        if (vsn->exponent < vsm->exponent) {
                struct vfp_single *t = vsn;
                vsn = vsm;
                vsm = t;
        }

        /*
         * Is 'n' an infinity or a NaN?  Note that 'm' may be a number,
         * infinity or a NaN here.
         */
        if (vsn->exponent == 255)
                return vfp_single_fadd_nonnumber(vsd, vsn, vsm, fpscr);

        /*
         * We have two proper numbers, where 'vsn' is the larger magnitude.
         *
         * Copy 'n' to 'd' before doing the arithmetic.
         */
        *vsd = *vsn;

        /*
         * Align both numbers.
         */
        exp_diff = vsn->exponent - vsm->exponent;
        m_sig = vfp_shiftright32jamming(vsm->significand, exp_diff);

        /*
         * If the signs are different, we are really subtracting.
         */
        if (vsn->sign ^ vsm->sign) {
                m_sig = vsn->significand - m_sig;
                if ((s32)m_sig < 0) {
                        vsd->sign = vfp_sign_negate(vsd->sign);
                        m_sig = -m_sig;
                } else if (m_sig == 0) {
                        vsd->sign = (fpscr & FPSCR_RMODE_MASK) ==
                                      FPSCR_ROUND_MINUSINF ? 0x8000 : 0;
                }
        } else {
                m_sig = vsn->significand + m_sig;
        }
        vsd->significand = m_sig;

        return 0;
}

static u32
vfp_single_multiply(struct vfp_single *vsd, struct vfp_single *vsn, struct vfp_single *vsm, u32 fpscr)
{
        vfp_single_dump("VSN", vsn);
        vfp_single_dump("VSM", vsm);

        /*
         * Ensure that 'n' is the largest magnitude number.  Note that
         * if 'n' and 'm' have equal exponents, we do not swap them.
         * This ensures that NaN propagation works correctly.
         */
        if (vsn->exponent < vsm->exponent) {
                struct vfp_single *t = vsn;
                vsn = vsm;
                vsm = t;
                pr_debug("VFP: swapping M <-> N\n");
        }

        vsd->sign = vsn->sign ^ vsm->sign;

        /*
         * If 'n' is an infinity or NaN, handle it.  'm' may be anything.
         */
        if (vsn->exponent == 255) {
                if (vsn->significand || (vsm->exponent == 255 && vsm->significand))
                        return vfp_propagate_nan(vsd, vsn, vsm, fpscr);
                if ((vsm->exponent | vsm->significand) == 0) {
                        *vsd = vfp_single_default_qnan;
                        return FPSCR_IOC;
                }
                vsd->exponent = vsn->exponent;
                vsd->significand = 0;
                return 0;
        }

        /*
         * If 'm' is zero, the result is always zero.  In this case,
         * 'n' may be zero or a number, but it doesn't matter which.
         */
        if ((vsm->exponent | vsm->significand) == 0) {
                vsd->exponent = 0;
                vsd->significand = 0;
                return 0;
        }

        /*
         * We add 2 to the destination exponent for the same reason as
         * the addition case - though this time we have +1 from each
         * input operand.
         */
        vsd->exponent = vsn->exponent + vsm->exponent - 127 + 2;
        vsd->significand = vfp_hi64to32jamming((u64)vsn->significand * vsm->significand);

        vfp_single_dump("VSD", vsd);
        return 0;
}

#define NEG_MULTIPLY    (1 << 0)
#define NEG_SUBTRACT    (1 << 1)

static u32
vfp_single_multiply_accumulate(int sd, int sn, s32 m, u32 fpscr, u32 negate, char *func)
{
        struct vfp_single vsd, vsp, vsn, vsm;
        u32 exceptions;
        s32 v;

        v = vfp_get_float(sn);
        pr_debug("VFP: s%u = %08x\n", sn, v);
        vfp_single_unpack(&vsn, v);
        if (vsn.exponent == 0 && vsn.significand)
                vfp_single_normalise_denormal(&vsn);

        vfp_single_unpack(&vsm, m);
        if (vsm.exponent == 0 && vsm.significand)
                vfp_single_normalise_denormal(&vsm);

        exceptions = vfp_single_multiply(&vsp, &vsn, &vsm, fpscr);
        if (negate & NEG_MULTIPLY)
                vsp.sign = vfp_sign_negate(vsp.sign);

        v = vfp_get_float(sd);
        pr_debug("VFP: s%u = %08x\n", sd, v);
        vfp_single_unpack(&vsn, v);
        if (negate & NEG_SUBTRACT)
                vsn.sign = vfp_sign_negate(vsn.sign);

        exceptions |= vfp_single_add(&vsd, &vsn, &vsp, fpscr);

        return vfp_single_normaliseround(sd, &vsd, fpscr, exceptions, func);
}

/*
 * Standard operations
 */

/*
 * sd = sd + (sn * sm)
 */
static u32 vfp_single_fmac(int sd, int sn, s32 m, u32 fpscr)
{
        return vfp_single_multiply_accumulate(sd, sn, m, fpscr, 0, "fmac");
}

/*
 * sd = sd - (sn * sm)
 */
static u32 vfp_single_fnmac(int sd, int sn, s32 m, u32 fpscr)
{
        return vfp_single_multiply_accumulate(sd, sn, m, fpscr, NEG_MULTIPLY, "fnmac");
}

/*
 * sd = -sd + (sn * sm)
 */
static u32 vfp_single_fmsc(int sd, int sn, s32 m, u32 fpscr)
{
        return vfp_single_multiply_accumulate(sd, sn, m, fpscr, NEG_SUBTRACT, "fmsc");
}

/*
 * sd = -sd - (sn * sm)
 */
static u32 vfp_single_fnmsc(int sd, int sn, s32 m, u32 fpscr)
{
        return vfp_single_multiply_accumulate(sd, sn, m, fpscr, NEG_SUBTRACT | NEG_MULTIPLY, "fnmsc");
}

/*
 * sd = sn * sm
 */
static u32 vfp_single_fmul(int sd, int sn, s32 m, u32 fpscr)
{
        struct vfp_single vsd, vsn, vsm;
        u32 exceptions;
        s32 n = vfp_get_float(sn);

        pr_debug("VFP: s%u = %08x\n", sn, n);

        vfp_single_unpack(&vsn, n);
        if (vsn.exponent == 0 && vsn.significand)
                vfp_single_normalise_denormal(&vsn);

        vfp_single_unpack(&vsm, m);
        if (vsm.exponent == 0 && vsm.significand)
                vfp_single_normalise_denormal(&vsm);

        exceptions = vfp_single_multiply(&vsd, &vsn, &vsm, fpscr);
        return vfp_single_normaliseround(sd, &vsd, fpscr, exceptions, "fmul");
}

/*
 * sd = -(sn * sm)
 */
static u32 vfp_single_fnmul(int sd, int sn, s32 m, u32 fpscr)
{
        struct vfp_single vsd, vsn, vsm;
        u32 exceptions;
        s32 n = vfp_get_float(sn);

        pr_debug("VFP: s%u = %08x\n", sn, n);

        vfp_single_unpack(&vsn, n);
        if (vsn.exponent == 0 && vsn.significand)
                vfp_single_normalise_denormal(&vsn);

        vfp_single_unpack(&vsm, m);
        if (vsm.exponent == 0 && vsm.significand)
                vfp_single_normalise_denormal(&vsm);

        exceptions = vfp_single_multiply(&vsd, &vsn, &vsm, fpscr);
        vsd.sign = vfp_sign_negate(vsd.sign);
        return vfp_single_normaliseround(sd, &vsd, fpscr, exceptions, "fnmul");
}

/*
 * sd = sn + sm
 */
static u32 vfp_single_fadd(int sd, int sn, s32 m, u32 fpscr)
{
        struct vfp_single vsd, vsn, vsm;
        u32 exceptions;
        s32 n = vfp_get_float(sn);

        pr_debug("VFP: s%u = %08x\n", sn, n);

        /*
         * Unpack and normalise denormals.
         */
        vfp_single_unpack(&vsn, n);
        if (vsn.exponent == 0 && vsn.significand)
                vfp_single_normalise_denormal(&vsn);

        vfp_single_unpack(&vsm, m);
        if (vsm.exponent == 0 && vsm.significand)
                vfp_single_normalise_denormal(&vsm);

        exceptions = vfp_single_add(&vsd, &vsn, &vsm, fpscr);

        return vfp_single_normaliseround(sd, &vsd, fpscr, exceptions, "fadd");
}

/*
 * sd = sn - sm
 */
static u32 vfp_single_fsub(int sd, int sn, s32 m, u32 fpscr)
{
        /*
         * Subtraction is addition with one sign inverted.
         */
        return vfp_single_fadd(sd, sn, vfp_single_packed_negate(m), fpscr);
}

/*
 * sd = sn / sm
 */
static u32 vfp_single_fdiv(int sd, int sn, s32 m, u32 fpscr)
{
        struct vfp_single vsd, vsn, vsm;
        u32 exceptions = 0;
        s32 n = vfp_get_float(sn);
        int tm, tn;

        pr_debug("VFP: s%u = %08x\n", sn, n);

        vfp_single_unpack(&vsn, n);
        vfp_single_unpack(&vsm, m);

        vsd.sign = vsn.sign ^ vsm.sign;

        tn = vfp_single_type(&vsn);
        tm = vfp_single_type(&vsm);

        /*
         * Is n a NAN?
         */
        if (tn & VFP_NAN)
                goto vsn_nan;

        /*
         * Is m a NAN?
         */
        if (tm & VFP_NAN)
                goto vsm_nan;

        /*
         * If n and m are infinity, the result is invalid
         * If n and m are zero, the result is invalid
         */
        if (tm & tn & (VFP_INFINITY|VFP_ZERO))
                goto invalid;

        /*
         * If n is infinity, the result is infinity
         */
        if (tn & VFP_INFINITY)
                goto infinity;

        /*
         * If m is zero, raise div0 exception
         */
        if (tm & VFP_ZERO)
                goto divzero;

        /*
         * If m is infinity, or n is zero, the result is zero
         */
        if (tm & VFP_INFINITY || tn & VFP_ZERO)
                goto zero;

        if (tn & VFP_DENORMAL)
                vfp_single_normalise_denormal(&vsn);
        if (tm & VFP_DENORMAL)
                vfp_single_normalise_denormal(&vsm);

        /*
         * Ok, we have two numbers, we can perform division.
         */
        vsd.exponent = vsn.exponent - vsm.exponent + 127 - 1;
        vsm.significand <<= 1;
        if (vsm.significand <= (2 * vsn.significand)) {
                vsn.significand >>= 1;
                vsd.exponent++;
        }
        vsd.significand = ((u64)vsn.significand << 32) / vsm.significand;
        if ((vsd.significand & 0x3f) == 0)
                vsd.significand |= ((u64)vsm.significand * vsd.significand != (u64)vsn.significand << 32);

        return vfp_single_normaliseround(sd, &vsd, fpscr, 0, "fdiv");

 vsn_nan:
        exceptions = vfp_propagate_nan(&vsd, &vsn, &vsm, fpscr);
 pack:
        vfp_put_float(sd, vfp_single_pack(&vsd));
        return exceptions;

 vsm_nan:
        exceptions = vfp_propagate_nan(&vsd, &vsm, &vsn, fpscr);
        goto pack;

 zero:
        vsd.exponent = 0;
        vsd.significand = 0;
        goto pack;

 divzero:
        exceptions = FPSCR_DZC;
 infinity:
        vsd.exponent = 255;
        vsd.significand = 0;
        goto pack;

 invalid:
        vfp_put_float(sd, vfp_single_pack(&vfp_single_default_qnan));
        return FPSCR_IOC;
}

static u32 (* const fop_fns[16])(int sd, int sn, s32 m, u32 fpscr) = {
        [FOP_TO_IDX(FOP_FMAC)]  = vfp_single_fmac,
        [FOP_TO_IDX(FOP_FNMAC)] = vfp_single_fnmac,
        [FOP_TO_IDX(FOP_FMSC)]  = vfp_single_fmsc,
        [FOP_TO_IDX(FOP_FNMSC)] = vfp_single_fnmsc,
        [FOP_TO_IDX(FOP_FMUL)]  = vfp_single_fmul,
        [FOP_TO_IDX(FOP_FNMUL)] = vfp_single_fnmul,
        [FOP_TO_IDX(FOP_FADD)]  = vfp_single_fadd,
        [FOP_TO_IDX(FOP_FSUB)]  = vfp_single_fsub,
        [FOP_TO_IDX(FOP_FDIV)]  = vfp_single_fdiv,
};

#define FREG_BANK(x)    ((x) & 0x18)
#define FREG_IDX(x)     ((x) & 7)

u32 vfp_single_cpdo(u32 inst, u32 fpscr)
{
        u32 op = inst & FOP_MASK;
        u32 exceptions = 0;
        unsigned int sd = vfp_get_sd(inst);
        unsigned int sn = vfp_get_sn(inst);
        unsigned int sm = vfp_get_sm(inst);
        unsigned int vecitr, veclen, vecstride;
        u32 (*fop)(int, int, s32, u32);

        veclen = fpscr & FPSCR_LENGTH_MASK;
        vecstride = 1 + ((fpscr & FPSCR_STRIDE_MASK) == FPSCR_STRIDE_MASK);

        /*
         * If destination bank is zero, vector length is always '1'.
         * ARM DDI0100F C5.1.3, C5.3.2.
         */
        if (FREG_BANK(sd) == 0)
                veclen = 0;

        pr_debug("VFP: vecstride=%u veclen=%u\n", vecstride,
                 (veclen >> FPSCR_LENGTH_BIT) + 1);

        fop = (op == FOP_EXT) ? fop_extfns[sn] : fop_fns[FOP_TO_IDX(op)];
        if (!fop)
                goto invalid;

        for (vecitr = 0; vecitr <= veclen; vecitr += 1 << FPSCR_LENGTH_BIT) {
                s32 m = vfp_get_float(sm);
                u32 except;

                if (op == FOP_EXT)
                        pr_debug("VFP: itr%d (s%u) = op[%u] (s%u=%08x)\n",
                                 vecitr >> FPSCR_LENGTH_BIT, sd, sn, sm, m);
                else
                        pr_debug("VFP: itr%d (s%u) = (s%u) op[%u] (s%u=%08x)\n",
                                 vecitr >> FPSCR_LENGTH_BIT, sd, sn,
                                 FOP_TO_IDX(op), sm, m);

                except = fop(sd, sn, m, fpscr);
                pr_debug("VFP: itr%d: exceptions=%08x\n",
                         vecitr >> FPSCR_LENGTH_BIT, except);

                exceptions |= except;

                /*
                 * This ensures that comparisons only operate on scalars;
                 * comparisons always return with one FPSCR status bit set.
                 */
                if (except & (FPSCR_N|FPSCR_Z|FPSCR_C|FPSCR_V))
                        break;

                /*
                 * CHECK: It appears to be undefined whether we stop when
                 * we encounter an exception.  We continue.
                 */

                sd = FREG_BANK(sd) + ((FREG_IDX(sd) + vecstride) & 7);
                sn = FREG_BANK(sn) + ((FREG_IDX(sn) + vecstride) & 7);
                if (FREG_BANK(sm) != 0)
                        sm = FREG_BANK(sm) + ((FREG_IDX(sm) + vecstride) & 7);
        }
        return exceptions;

 invalid:
        return (u32)-1;
}