arch/arm/vfp/vfp.h

   1 /*
   2  *  linux/arch/arm/vfp/vfp.h
   3  *
   4  *  Copyright (C) 2004 ARM Limited.
   5  *  Written by Deep Blue Solutions Limited.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 static inline u32 vfp_shiftright32jamming(u32 val, unsigned int shift)
  13 {
  14         if (shift) {
  15                 if (shift < 32)
  16                         val = val >> shift | ((val << (32 - shift)) != 0);
  17                 else
  18                         val = val != 0;
  19         }
  20         return val;
  21 }
  22
  23 static inline u64 vfp_shiftright64jamming(u64 val, unsigned int shift)
  24 {
  25         if (shift) {
  26                 if (shift < 64)
  27                         val = val >> shift | ((val << (64 - shift)) != 0);
  28                 else
  29                         val = val != 0;
  30         }
  31         return val;
  32 }
  33
  34 static inline u32 vfp_hi64to32jamming(u64 val)
  35 {
  36         u32 v;
  37
  38         asm(
  39         "cmp    %Q1, #1         @ vfp_hi64to32jamming\n\t"
  40         "movcc  %0, %R1\n\t"
  41         "orrcs  %0, %R1, #1"
  42         : "=r" (v) : "r" (val) : "cc");
  43
  44         return v;
  45 }
  46
  47 static inline void add128(u64 *resh, u64 *resl, u64 nh, u64 nl, u64 mh, u64 ml)
  48 {
  49         asm(    "adds   %Q0, %Q2, %Q4\n\t"
  50                 "adcs   %R0, %R2, %R4\n\t"
  51                 "adcs   %Q1, %Q3, %Q5\n\t"
  52                 "adc    %R1, %R3, %R5"
  53             : "=r" (nl), "=r" (nh)
  54             : "0" (nl), "1" (nh), "r" (ml), "r" (mh)
  55             : "cc");
  56         *resh = nh;
  57         *resl = nl;
  58 }
  59
  60 static inline void sub128(u64 *resh, u64 *resl, u64 nh, u64 nl, u64 mh, u64 ml)
  61 {
  62         asm(    "subs   %Q0, %Q2, %Q4\n\t"
  63                 "sbcs   %R0, %R2, %R4\n\t"
  64                 "sbcs   %Q1, %Q3, %Q5\n\t"
  65                 "sbc    %R1, %R3, %R5\n\t"
  66             : "=r" (nl), "=r" (nh)
  67             : "0" (nl), "1" (nh), "r" (ml), "r" (mh)
  68             : "cc");
  69         *resh = nh;
  70         *resl = nl;
  71 }
  72
  73 static inline void mul64to128(u64 *resh, u64 *resl, u64 n, u64 m)
  74 {
  75         u32 nh, nl, mh, ml;
  76         u64 rh, rma, rmb, rl;
  77
  78         nl = n;
  79         ml = m;
  80         rl = (u64)nl * ml;
  81
  82         nh = n >> 32;
  83         rma = (u64)nh * ml;
  84
  85         mh = m >> 32;
  86         rmb = (u64)nl * mh;
  87         rma += rmb;
  88
  89         rh = (u64)nh * mh;
  90         rh += ((u64)(rma < rmb) << 32) + (rma >> 32);
  91
  92         rma <<= 32;
  93         rl += rma;
  94         rh += (rl < rma);
  95
  96         *resl = rl;
  97         *resh = rh;
  98 }
  99
 100 static inline void shift64left(u64 *resh, u64 *resl, u64 n)
 101 {
 102         *resh = n >> 63;
 103         *resl = n << 1;
 104 }
 105
 106 static inline u64 vfp_hi64multiply64(u64 n, u64 m)
 107 {
 108         u64 rh, rl;
 109         mul64to128(&rh, &rl, n, m);
 110         return rh | (rl != 0);
 111 }
 112
 113 static inline u64 vfp_estimate_div128to64(u64 nh, u64 nl, u64 m)
 114 {
 115         u64 mh, ml, remh, reml, termh, terml, z;
 116
 117         if (nh >= m)
 118                 return ~0ULL;
 119         mh = m >> 32;
 120         if (mh << 32 <= nh) {
 121                 z = 0xffffffff00000000ULL;
 122         } else {
 123                 z = nh;
 124                 do_div(z, mh);
 125                 z <<= 32;
 126         }
 127         mul64to128(&termh, &terml, m, z);
 128         sub128(&remh, &reml, nh, nl, termh, terml);
 129         ml = m << 32;
 130         while ((s64)remh < 0) {
 131                 z -= 0x100000000ULL;
 132                 add128(&remh, &reml, remh, reml, mh, ml);
 133         }
 134         remh = (remh << 32) | (reml >> 32);
 135         if (mh << 32 <= remh) {
 136                 z |= 0xffffffff;
 137         } else {
 138                 do_div(remh, mh);
 139                 z |= remh;
 140         }
 141         return z;
 142 }
 143
 144 /*
 145  * Operations on unpacked elements
 146  */
 147 #define vfp_sign_negate(sign)   (sign ^ 0x8000)
 148
 149 /*
 150  * Single-precision
 151  */
 152 struct vfp_single {
 153         s16     exponent;
 154         u16     sign;
 155         u32     significand;
 156 };
 157
 158 asmlinkage s32 vfp_get_float(unsigned int reg);
 159 asmlinkage void vfp_put_float(s32 val, unsigned int reg);
 160
 161 /*
 162  * VFP_SINGLE_MANTISSA_BITS - number of bits in the mantissa
 163  * VFP_SINGLE_EXPONENT_BITS - number of bits in the exponent
 164  * VFP_SINGLE_LOW_BITS - number of low bits in the unpacked significand
 165  *  which are not propagated to the float upon packing.
 166  */
 167 #define VFP_SINGLE_MANTISSA_BITS        (23)
 168 #define VFP_SINGLE_EXPONENT_BITS        (8)
 169 #define VFP_SINGLE_LOW_BITS             (32 - VFP_SINGLE_MANTISSA_BITS - 2)
 170 #define VFP_SINGLE_LOW_BITS_MASK        ((1 << VFP_SINGLE_LOW_BITS) - 1)
 171
 172 /*
 173  * The bit in an unpacked float which indicates that it is a quiet NaN
 174  */
 175 #define VFP_SINGLE_SIGNIFICAND_QNAN     (1 << (VFP_SINGLE_MANTISSA_BITS - 1 + VFP_SINGLE_LOW_BITS))
 176
 177 /*
 178  * Operations on packed single-precision numbers
 179  */
 180 #define vfp_single_packed_sign(v)       ((v) & 0x80000000)
 181 #define vfp_single_packed_negate(v)     ((v) ^ 0x80000000)
 182 #define vfp_single_packed_abs(v)        ((v) & ~0x80000000)
 183 #define vfp_single_packed_exponent(v)   (((v) >> VFP_SINGLE_MANTISSA_BITS) & ((1 << VFP_SINGLE_EXPONENT_BITS) - 1))
 184 #define vfp_single_packed_mantissa(v)   ((v) & ((1 << VFP_SINGLE_MANTISSA_BITS) - 1))
 185
 186 /*
 187  * Unpack a single-precision float.  Note that this returns the magnitude
 188  * of the single-precision float mantissa with the 1. if necessary,
 189  * aligned to bit 30.
 190  */
 191 static inline void vfp_single_unpack(struct vfp_single *s, s32 val)
 192 {
 193         u32 significand;
 194
 195         s->sign = vfp_single_packed_sign(val) >> 16,
 196         s->exponent = vfp_single_packed_exponent(val);
 197
 198         significand = (u32) val;
 199         significand = (significand << (32 - VFP_SINGLE_MANTISSA_BITS)) >> 2;
 200         if (s->exponent && s->exponent != 255)
 201                 significand |= 0x40000000;
 202         s->significand = significand;
 203 }
 204
 205 /*
 206  * Re-pack a single-precision float.  This assumes that the float is
 207  * already normalised such that the MSB is bit 30, _not_ bit 31.
 208  */
 209 static inline s32 vfp_single_pack(struct vfp_single *s)
 210 {
 211         u32 val;
 212         val = (s->sign << 16) +
 213               (s->exponent << VFP_SINGLE_MANTISSA_BITS) +
 214               (s->significand >> VFP_SINGLE_LOW_BITS);
 215         return (s32)val;
 216 }
 217
 218 #define VFP_NUMBER              (1<<0)
 219 #define VFP_ZERO                (1<<1)
 220 #define VFP_DENORMAL            (1<<2)
 221 #define VFP_INFINITY            (1<<3)
 222 #define VFP_NAN                 (1<<4)
 223 #define VFP_NAN_SIGNAL          (1<<5)
 224
 225 #define VFP_QNAN                (VFP_NAN)
 226 #define VFP_SNAN                (VFP_NAN|VFP_NAN_SIGNAL)
 227
 228 static inline int vfp_single_type(struct vfp_single *s)
 229 {
 230         int type = VFP_NUMBER;
 231         if (s->exponent == 255) {
 232                 if (s->significand == 0)
 233                         type = VFP_INFINITY;
 234                 else if (s->significand & VFP_SINGLE_SIGNIFICAND_QNAN)
 235                         type = VFP_QNAN;
 236                 else
 237                         type = VFP_SNAN;
 238         } else if (s->exponent == 0) {
 239                 if (s->significand == 0)
 240                         type |= VFP_ZERO;
 241                 else
 242                         type |= VFP_DENORMAL;
 243         }
 244         return type;
 245 }
 246
 247 #ifndef DEBUG
 248 #define vfp_single_normaliseround(sd,vsd,fpscr,except,func) __vfp_single_normaliseround(sd,vsd,fpscr,except)
 249 u32 __vfp_single_normaliseround(int sd, struct vfp_single *vs, u32 fpscr, u32 exceptions);
 250 #else
 251 u32 vfp_single_normaliseround(int sd, struct vfp_single *vs, u32 fpscr, u32 exceptions, const char *func);
 252 #endif
 253
 254 /*
 255  * Double-precision
 256  */
 257 struct vfp_double {
 258         s16     exponent;
 259         u16     sign;
 260         u64     significand;
 261 };
 262
 263 /*
 264  * VFP_REG_ZERO is a special register number for vfp_get_double
 265  * which returns (double)0.0.  This is useful for the compare with
 266  * zero instructions.
 267  */
 268 #ifdef CONFIG_VFPv3
 269 #define VFP_REG_ZERO    32
 270 #else
 271 #define VFP_REG_ZERO    16
 272 #endif
 273 asmlinkage u64 vfp_get_double(unsigned int reg);
 274 asmlinkage void vfp_put_double(u64 val, unsigned int reg);
 275
 276 #define VFP_DOUBLE_MANTISSA_BITS        (52)
 277 #define VFP_DOUBLE_EXPONENT_BITS        (11)
 278 #define VFP_DOUBLE_LOW_BITS             (64 - VFP_DOUBLE_MANTISSA_BITS - 2)
 279 #define VFP_DOUBLE_LOW_BITS_MASK        ((1 << VFP_DOUBLE_LOW_BITS) - 1)
 280
 281 /*
 282  * The bit in an unpacked double which indicates that it is a quiet NaN
 283  */
 284 #define VFP_DOUBLE_SIGNIFICAND_QNAN     (1ULL << (VFP_DOUBLE_MANTISSA_BITS - 1 + VFP_DOUBLE_LOW_BITS))
 285
 286 /*
 287  * Operations on packed single-precision numbers
 288  */
 289 #define vfp_double_packed_sign(v)       ((v) & (1ULL << 63))
 290 #define vfp_double_packed_negate(v)     ((v) ^ (1ULL << 63))
 291 #define vfp_double_packed_abs(v)        ((v) & ~(1ULL << 63))
 292 #define vfp_double_packed_exponent(v)   (((v) >> VFP_DOUBLE_MANTISSA_BITS) & ((1 << VFP_DOUBLE_EXPONENT_BITS) - 1))
 293 #define vfp_double_packed_mantissa(v)   ((v) & ((1ULL << VFP_DOUBLE_MANTISSA_BITS) - 1))
 294
 295 /*
 296  * Unpack a double-precision float.  Note that this returns the magnitude
 297  * of the double-precision float mantissa with the 1. if necessary,
 298  * aligned to bit 62.
 299  */
 300 static inline void vfp_double_unpack(struct vfp_double *s, s64 val)
 301 {
 302         u64 significand;
 303
 304         s->sign = vfp_double_packed_sign(val) >> 48;
 305         s->exponent = vfp_double_packed_exponent(val);
 306
 307         significand = (u64) val;
 308         significand = (significand << (64 - VFP_DOUBLE_MANTISSA_BITS)) >> 2;
 309         if (s->exponent && s->exponent != 2047)
 310                 significand |= (1ULL << 62);
 311         s->significand = significand;
 312 }
 313
 314 /*
 315  * Re-pack a double-precision float.  This assumes that the float is
 316  * already normalised such that the MSB is bit 30, _not_ bit 31.
 317  */
 318 static inline s64 vfp_double_pack(struct vfp_double *s)
 319 {
 320         u64 val;
 321         val = ((u64)s->sign << 48) +
 322               ((u64)s->exponent << VFP_DOUBLE_MANTISSA_BITS) +
 323               (s->significand >> VFP_DOUBLE_LOW_BITS);
 324         return (s64)val;
 325 }
 326
 327 static inline int vfp_double_type(struct vfp_double *s)
 328 {
 329         int type = VFP_NUMBER;
 330         if (s->exponent == 2047) {
 331                 if (s->significand == 0)
 332                         type = VFP_INFINITY;
 333                 else if (s->significand & VFP_DOUBLE_SIGNIFICAND_QNAN)
 334                         type = VFP_QNAN;
 335                 else
 336                         type = VFP_SNAN;
 337         } else if (s->exponent == 0) {
 338                 if (s->significand == 0)
 339                         type |= VFP_ZERO;
 340                 else
 341                         type |= VFP_DENORMAL;
 342         }
 343         return type;
 344 }
 345
 346 u32 vfp_double_normaliseround(int dd, struct vfp_double *vd, u32 fpscr, u32 exceptions, const char *func);
 347
 348 u32 vfp_estimate_sqrt_significand(u32 exponent, u32 significand);
 349
 350 /*
 351  * A special flag to tell the normalisation code not to normalise.
 352  */
 353 #define VFP_NAN_FLAG    0x100
 354
 355 /*
 356  * A bit pattern used to indicate the initial (unset) value of the
 357  * exception mask, in case nothing handles an instruction.  This
 358  * doesn't include the NAN flag, which get masked out before
 359  * we check for an error.
 360  */
 361 #define VFP_EXCEPTION_ERROR     ((u32)-1 & ~VFP_NAN_FLAG)
 362
 363 /*
 364  * A flag to tell vfp instruction type.
 365  *  OP_SCALAR - this operation always operates in scalar mode
 366  *  OP_SD - the instruction exceptionally writes to a single precision result.
 367  *  OP_DD - the instruction exceptionally writes to a double precision result.
 368  *  OP_SM - the instruction exceptionally reads from a single precision operand.
 369  */
 370 #define OP_SCALAR       (1 << 0)
 371 #define OP_SD           (1 << 1)
 372 #define OP_DD           (1 << 1)
 373 #define OP_SM           (1 << 2)
 374
 375 struct op {
 376         u32 (* const fn)(int dd, int dn, int dm, u32 fpscr);
 377         u32 flags;
 378 };
 379
 380 asmlinkage void vfp_save_state(void *location, u32 fpexc);