vfp.h

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/*
 *  linux/arch/arm/vfp/vfp.h
 *
 *  Copyright (C) 2004 ARM Limited.
 *  Written by Deep Blue Solutions Limited.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

static inline u32 vfp_shiftright32jamming(u32 val, unsigned int shift)
{
    if (shift) {
        if (shift < 32)
            val = val >> shift | ((val << (32 - shift)) != 0);
        else
            val = val != 0;
    }
    return val;
}

static inline u64 vfp_shiftright64jamming(u64 val, unsigned int shift)
{
    if (shift) {
        if (shift < 64)
            val = val >> shift | ((val << (64 - shift)) != 0);
        else
            val = val != 0;
    }
    return val;
}

static inline u32 vfp_hi64to32jamming(u64 val)
{
    u32 v;

    asm(
    "cmp    %Q1, #1     @ vfp_hi64to32jamming\n\t"
    "movcc  %0, %R1\n\t"
    "orrcs  %0, %R1, #1"
    : "=r" (v) : "r" (val) : "cc");

    return v;
}

static inline void add128(u64 *resh, u64 *resl, u64 nh, u64 nl, u64 mh, u64 ml)
{
    asm(    "adds   %Q0, %Q2, %Q4\n\t"
        "adcs   %R0, %R2, %R4\n\t"
        "adcs   %Q1, %Q3, %Q5\n\t"
        "adc    %R1, %R3, %R5"
        : "=r" (nl), "=r" (nh)
        : "0" (nl), "1" (nh), "r" (ml), "r" (mh)
        : "cc");
    *resh = nh;
    *resl = nl;
}

static inline void sub128(u64 *resh, u64 *resl, u64 nh, u64 nl, u64 mh, u64 ml)
{
    asm(    "subs   %Q0, %Q2, %Q4\n\t"
        "sbcs   %R0, %R2, %R4\n\t"
        "sbcs   %Q1, %Q3, %Q5\n\t"
        "sbc    %R1, %R3, %R5\n\t"
        : "=r" (nl), "=r" (nh)
        : "0" (nl), "1" (nh), "r" (ml), "r" (mh)
        : "cc");
    *resh = nh;
    *resl = nl;
}

static inline void mul64to128(u64 *resh, u64 *resl, u64 n, u64 m)
{
    u32 nh, nl, mh, ml;
    u64 rh, rma, rmb, rl;

    nl = n;
    ml = m;
    rl = (u64)nl * ml;

    nh = n >> 32;
    rma = (u64)nh * ml;

    mh = m >> 32;
    rmb = (u64)nl * mh;
    rma += rmb;

    rh = (u64)nh * mh;
    rh += ((u64)(rma < rmb) << 32) + (rma >> 32);

    rma <<= 32;
    rl += rma;
    rh += (rl < rma);

    *resl = rl;
    *resh = rh;
}

static inline void shift64left(u64 *resh, u64 *resl, u64 n)
{
    *resh = n >> 63;
    *resl = n << 1;
}

static inline u64 vfp_hi64multiply64(u64 n, u64 m)
{
    u64 rh, rl;
    mul64to128(&rh, &rl, n, m);
    return rh | (rl != 0);
}

static inline u64 vfp_estimate_div128to64(u64 nh, u64 nl, u64 m)
{
    u64 mh, ml, remh, reml, termh, terml, z;

    if (nh >= m)
        return ~0ULL;
    mh = m >> 32;
    if (mh << 32 <= nh) {
        z = 0xffffffff00000000ULL;
    } else {
        z = nh;
        do_div(z, mh);
        z <<= 32;
    }
    mul64to128(&termh, &terml, m, z);
    sub128(&remh, &reml, nh, nl, termh, terml);
    ml = m << 32;
    while ((s64)remh < 0) {
        z -= 0x100000000ULL;
        add128(&remh, &reml, remh, reml, mh, ml);
    }
    remh = (remh << 32) | (reml >> 32);
    if (mh << 32 <= remh) {
        z |= 0xffffffff;
    } else {
        do_div(remh, mh);
        z |= remh;
    }
    return z;
}

/*
 * Operations on unpacked elements
 */
#define vfp_sign_negate(sign)   (sign ^ 0x8000)

/*
 * Single-precision
 */
struct vfp_single {
    s16 exponent;
    u16 sign;
    u32 significand;
};

extern s32 vfp_get_float(unsigned int reg);
extern void vfp_put_float(s32 val, unsigned int reg);

/*
 * VFP_SINGLE_MANTISSA_BITS - number of bits in the mantissa
 * VFP_SINGLE_EXPONENT_BITS - number of bits in the exponent
 * VFP_SINGLE_LOW_BITS - number of low bits in the unpacked significand
 *  which are not propagated to the float upon packing.
 */
#define VFP_SINGLE_MANTISSA_BITS    (23)
#define VFP_SINGLE_EXPONENT_BITS    (8)
#define VFP_SINGLE_LOW_BITS     (32 - VFP_SINGLE_MANTISSA_BITS - 2)
#define VFP_SINGLE_LOW_BITS_MASK    ((1 << VFP_SINGLE_LOW_BITS) - 1)

/*
 * The bit in an unpacked float which indicates that it is a quiet NaN
 */
#define VFP_SINGLE_SIGNIFICAND_QNAN (1 << (VFP_SINGLE_MANTISSA_BITS - 1 + VFP_SINGLE_LOW_BITS))

/*
 * Operations on packed single-precision numbers
 */
#define vfp_single_packed_sign(v)   ((v) & 0x80000000)
#define vfp_single_packed_negate(v) ((v) ^ 0x80000000)
#define vfp_single_packed_abs(v)    ((v) & ~0x80000000)
#define vfp_single_packed_exponent(v)   (((v) >> VFP_SINGLE_MANTISSA_BITS) & ((1 << VFP_SINGLE_EXPONENT_BITS) - 1))
#define vfp_single_packed_mantissa(v)   ((v) & ((1 << VFP_SINGLE_MANTISSA_BITS) - 1))

/*
 * Unpack a single-precision float.  Note that this returns the magnitude
 * of the single-precision float mantissa with the 1. if necessary,
 * aligned to bit 30.
 */
static inline void vfp_single_unpack(struct vfp_single *s, s32 val)
{
    u32 significand;

    s->sign = vfp_single_packed_sign(val) >> 16,
    s->exponent = vfp_single_packed_exponent(val);

    significand = (u32) val;
    significand = (significand << (32 - VFP_SINGLE_MANTISSA_BITS)) >> 2;
    if (s->exponent && s->exponent != 255)
        significand |= 0x40000000;
    s->significand = significand;
}

/*
 * Re-pack a single-precision float.  This assumes that the float is
 * already normalised such that the MSB is bit 30, _not_ bit 31.
 */
static inline s32 vfp_single_pack(struct vfp_single *s)
{
    u32 val;
    val = (s->sign << 16) +
          (s->exponent << VFP_SINGLE_MANTISSA_BITS) +
          (s->significand >> VFP_SINGLE_LOW_BITS);
    return (s32)val;
}

#define VFP_NUMBER      (1<<0)
#define VFP_ZERO        (1<<1)
#define VFP_DENORMAL        (1<<2)
#define VFP_INFINITY        (1<<3)
#define VFP_NAN         (1<<4)
#define VFP_NAN_SIGNAL      (1<<5)

#define VFP_QNAN        (VFP_NAN)
#define VFP_SNAN        (VFP_NAN|VFP_NAN_SIGNAL)

static inline int vfp_single_type(struct vfp_single *s)
{
    int type = VFP_NUMBER;
    if (s->exponent == 255) {
        if (s->significand == 0)
            type = VFP_INFINITY;
        else if (s->significand & VFP_SINGLE_SIGNIFICAND_QNAN)
            type = VFP_QNAN;
        else
            type = VFP_SNAN;
    } else if (s->exponent == 0) {
        if (s->significand == 0)
            type |= VFP_ZERO;
        else
            type |= VFP_DENORMAL;
    }
    return type;
}

#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

/*
 * Double-precision
 */
struct vfp_double {
    s16 exponent;
    u16 sign;
    u64 significand;
};

/*
 * VFP_REG_ZERO is a special register number for vfp_get_double
 * which returns (double)0.0.  This is useful for the compare with
 * zero instructions.
 */
#ifdef CONFIG_VFPv3
#define VFP_REG_ZERO    32
#else
#define VFP_REG_ZERO    16
#endif
extern u64 vfp_get_double(unsigned int reg);
extern void vfp_put_double(u64 val, unsigned int reg);

#define VFP_DOUBLE_MANTISSA_BITS    (52)
#define VFP_DOUBLE_EXPONENT_BITS    (11)
#define VFP_DOUBLE_LOW_BITS     (64 - VFP_DOUBLE_MANTISSA_BITS - 2)
#define VFP_DOUBLE_LOW_BITS_MASK    ((1 << VFP_DOUBLE_LOW_BITS) - 1)

/*
 * The bit in an unpacked double which indicates that it is a quiet NaN
 */
#define VFP_DOUBLE_SIGNIFICAND_QNAN (1ULL << (VFP_DOUBLE_MANTISSA_BITS - 1 + VFP_DOUBLE_LOW_BITS))

/*
 * Operations on packed single-precision numbers
 */
#define vfp_double_packed_sign(v)   ((v) & (1ULL << 63))
#define vfp_double_packed_negate(v) ((v) ^ (1ULL << 63))
#define vfp_double_packed_abs(v)    ((v) & ~(1ULL << 63))
#define vfp_double_packed_exponent(v)   (((v) >> VFP_DOUBLE_MANTISSA_BITS) & ((1 << VFP_DOUBLE_EXPONENT_BITS) - 1))
#define vfp_double_packed_mantissa(v)   ((v) & ((1ULL << VFP_DOUBLE_MANTISSA_BITS) - 1))

/*
 * Unpack a double-precision float.  Note that this returns the magnitude
 * of the double-precision float mantissa with the 1. if necessary,
 * aligned to bit 62.
 */
static inline void vfp_double_unpack(struct vfp_double *s, s64 val)
{
    u64 significand;

    s->sign = vfp_double_packed_sign(val) >> 48;
    s->exponent = vfp_double_packed_exponent(val);

    significand = (u64) val;
    significand = (significand << (64 - VFP_DOUBLE_MANTISSA_BITS)) >> 2;
    if (s->exponent && s->exponent != 2047)
        significand |= (1ULL << 62);
    s->significand = significand;
}

/*
 * Re-pack a double-precision float.  This assumes that the float is
 * already normalised such that the MSB is bit 30, _not_ bit 31.
 */
static inline s64 vfp_double_pack(struct vfp_double *s)
{
    u64 val;
    val = ((u64)s->sign << 48) +
          ((u64)s->exponent << VFP_DOUBLE_MANTISSA_BITS) +
          (s->significand >> VFP_DOUBLE_LOW_BITS);
    return (s64)val;
}

static inline int vfp_double_type(struct vfp_double *s)
{
    int type = VFP_NUMBER;
    if (s->exponent == 2047) {
        if (s->significand == 0)
            type = VFP_INFINITY;
        else if (s->significand & VFP_DOUBLE_SIGNIFICAND_QNAN)
            type = VFP_QNAN;
        else
            type = VFP_SNAN;
    } else if (s->exponent == 0) {
        if (s->significand == 0)
            type |= VFP_ZERO;
        else
            type |= VFP_DENORMAL;
    }
    return type;
}

u32 vfp_double_normaliseround(int dd, struct vfp_double *vd, u32 fpscr, u32 exceptions, const char *func);

u32 vfp_estimate_sqrt_significand(u32 exponent, u32 significand);

/*
 * A special flag to tell the normalisation code not to normalise.
 */
#define VFP_NAN_FLAG    0x100

/*
 * A bit pattern used to indicate the initial (unset) value of the
 * exception mask, in case nothing handles an instruction.  This
 * doesn't include the NAN flag, which get masked out before
 * we check for an error.
 */
#define VFP_EXCEPTION_ERROR ((u32)-1 & ~VFP_NAN_FLAG)

/*
 * A flag to tell vfp instruction type.
 *  OP_SCALAR - this operation always operates in scalar mode
 *  OP_SD - the instruction exceptionally writes to a single precision result.
 *  OP_DD - the instruction exceptionally writes to a double precision result.
 *  OP_SM - the instruction exceptionally reads from a single precision operand.
 */
#define OP_SCALAR   (1 << 0)
#define OP_SD       (1 << 1)
#define OP_DD       (1 << 1)
#define OP_SM       (1 << 2)

struct op {
    u32 (* const fn)(int dd, int dn, int dm, u32 fpscr);
    u32 flags;
};

extern void vfp_save_state(void *location, u32 fpexc);