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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 | /* * Routines to emulate some Altivec/VMX instructions, specifically * those that can trap when given denormalized operands in Java mode. */ #include <linux/kernel.h> #include <linux/errno.h> #include <linux/sched.h> #include <asm/ptrace.h> #include <asm/processor.h> #include <asm/uaccess.h> /* Functions in vector.S */ extern void vaddfp(vector128 *dst, vector128 *a, vector128 *b); extern void vsubfp(vector128 *dst, vector128 *a, vector128 *b); extern void vmaddfp(vector128 *dst, vector128 *a, vector128 *b, vector128 *c); extern void vnmsubfp(vector128 *dst, vector128 *a, vector128 *b, vector128 *c); extern void vrefp(vector128 *dst, vector128 *src); extern void vrsqrtefp(vector128 *dst, vector128 *src); extern void vexptep(vector128 *dst, vector128 *src); static unsigned int exp2s[8] = { 0x800000, 0x8b95c2, 0x9837f0, 0xa5fed7, 0xb504f3, 0xc5672a, 0xd744fd, 0xeac0c7 }; /* * Computes an estimate of 2^x. The `s' argument is the 32-bit * single-precision floating-point representation of x. */ static unsigned int eexp2(unsigned int s) { int exp, pwr; unsigned int mant, frac; /* extract exponent field from input */ exp = ((s >> 23) & 0xff) - 127; if (exp > 7) { /* check for NaN input */ if (exp == 128 && (s & 0x7fffff) != 0) return s | 0x400000; /* return QNaN */ /* 2^-big = 0, 2^+big = +Inf */ return (s & 0x80000000)? 0: 0x7f800000; /* 0 or +Inf */ } if (exp < -23) return 0x3f800000; /* 1.0 */ /* convert to fixed point integer in 9.23 representation */ pwr = (s & 0x7fffff) | 0x800000; if (exp > 0) pwr <<= exp; else pwr >>= -exp; if (s & 0x80000000) pwr = -pwr; /* extract integer part, which becomes exponent part of result */ exp = (pwr >> 23) + 126; if (exp >= 254) return 0x7f800000; if (exp < -23) return 0; /* table lookup on top 3 bits of fraction to get mantissa */ mant = exp2s[(pwr >> 20) & 7]; /* linear interpolation using remaining 20 bits of fraction */ asm("mulhwu %0,%1,%2" : "=r" (frac) : "r" (pwr << 12), "r" (0x172b83ff)); asm("mulhwu %0,%1,%2" : "=r" (frac) : "r" (frac), "r" (mant)); mant += frac; if (exp >= 0) return mant + (exp << 23); /* denormalized result */ exp = -exp; mant += 1 << (exp - 1); return mant >> exp; } /* * Computes an estimate of log_2(x). The `s' argument is the 32-bit * single-precision floating-point representation of x. */ static unsigned int elog2(unsigned int s) { int exp, mant, lz, frac; exp = s & 0x7f800000; mant = s & 0x7fffff; if (exp == 0x7f800000) { /* Inf or NaN */ if (mant != 0) s |= 0x400000; /* turn NaN into QNaN */ return s; } if ((exp | mant) == 0) /* +0 or -0 */ return 0xff800000; /* return -Inf */ if (exp == 0) { /* denormalized */ asm("cntlzw %0,%1" : "=r" (lz) : "r" (mant)); mant <<= lz - 8; exp = (-118 - lz) << 23; } else { mant |= 0x800000; exp -= 127 << 23; } if (mant >= 0xb504f3) { /* 2^0.5 * 2^23 */ exp |= 0x400000; /* 0.5 * 2^23 */ asm("mulhwu %0,%1,%2" : "=r" (mant) : "r" (mant), "r" (0xb504f334)); /* 2^-0.5 * 2^32 */ } if (mant >= 0x9837f0) { /* 2^0.25 * 2^23 */ exp |= 0x200000; /* 0.25 * 2^23 */ asm("mulhwu %0,%1,%2" : "=r" (mant) : "r" (mant), "r" (0xd744fccb)); /* 2^-0.25 * 2^32 */ } if (mant >= 0x8b95c2) { /* 2^0.125 * 2^23 */ exp |= 0x100000; /* 0.125 * 2^23 */ asm("mulhwu %0,%1,%2" : "=r" (mant) : "r" (mant), "r" (0xeac0c6e8)); /* 2^-0.125 * 2^32 */ } if (mant > 0x800000) { /* 1.0 * 2^23 */ /* calculate (mant - 1) * 1.381097463 */ /* 1.381097463 == 0.125 / (2^0.125 - 1) */ asm("mulhwu %0,%1,%2" : "=r" (frac) : "r" ((mant - 0x800000) << 1), "r" (0xb0c7cd3a)); exp += frac; } s = exp & 0x80000000; if (exp != 0) { if (s) exp = -exp; asm("cntlzw %0,%1" : "=r" (lz) : "r" (exp)); lz = 8 - lz; if (lz > 0) exp >>= lz; else if (lz < 0) exp <<= -lz; s += ((lz + 126) << 23) + exp; } return s; } #define VSCR_SAT 1 static int ctsxs(unsigned int x, int scale, unsigned int *vscrp) { int exp, mant; exp = (x >> 23) & 0xff; mant = x & 0x7fffff; if (exp == 255 && mant != 0) return 0; /* NaN -> 0 */ exp = exp - 127 + scale; if (exp < 0) return 0; /* round towards zero */ if (exp >= 31) { /* saturate, unless the result would be -2^31 */ if (x + (scale << 23) != 0xcf000000) *vscrp |= VSCR_SAT; return (x & 0x80000000)? 0x80000000: 0x7fffffff; } mant |= 0x800000; mant = (mant << 7) >> (30 - exp); return (x & 0x80000000)? -mant: mant; } static unsigned int ctuxs(unsigned int x, int scale, unsigned int *vscrp) { int exp; unsigned int mant; exp = (x >> 23) & 0xff; mant = x & 0x7fffff; if (exp == 255 && mant != 0) return 0; /* NaN -> 0 */ exp = exp - 127 + scale; if (exp < 0) return 0; /* round towards zero */ if (x & 0x80000000) { /* negative => saturate to 0 */ *vscrp |= VSCR_SAT; return 0; } if (exp >= 32) { /* saturate */ *vscrp |= VSCR_SAT; return 0xffffffff; } mant |= 0x800000; mant = (mant << 8) >> (31 - exp); return mant; } /* Round to floating integer, towards 0 */ static unsigned int rfiz(unsigned int x) { int exp; exp = ((x >> 23) & 0xff) - 127; if (exp == 128 && (x & 0x7fffff) != 0) return x | 0x400000; /* NaN -> make it a QNaN */ if (exp >= 23) return x; /* it's an integer already (or Inf) */ if (exp < 0) return x & 0x80000000; /* |x| < 1.0 rounds to 0 */ return x & ~(0x7fffff >> exp); } /* Round to floating integer, towards +/- Inf */ static unsigned int rfii(unsigned int x) { int exp, mask; exp = ((x >> 23) & 0xff) - 127; if (exp == 128 && (x & 0x7fffff) != 0) return x | 0x400000; /* NaN -> make it a QNaN */ if (exp >= 23) return x; /* it's an integer already (or Inf) */ if ((x & 0x7fffffff) == 0) return x; /* +/-0 -> +/-0 */ if (exp < 0) /* 0 < |x| < 1.0 rounds to +/- 1.0 */ return (x & 0x80000000) | 0x3f800000; mask = 0x7fffff >> exp; /* mantissa overflows into exponent - that's OK, it can't overflow into the sign bit */ return (x + mask) & ~mask; } /* Round to floating integer, to nearest */ static unsigned int rfin(unsigned int x) { int exp, half; exp = ((x >> 23) & 0xff) - 127; if (exp == 128 && (x & 0x7fffff) != 0) return x | 0x400000; /* NaN -> make it a QNaN */ if (exp >= 23) return x; /* it's an integer already (or Inf) */ if (exp < -1) return x & 0x80000000; /* |x| < 0.5 -> +/-0 */ if (exp == -1) /* 0.5 <= |x| < 1.0 rounds to +/- 1.0 */ return (x & 0x80000000) | 0x3f800000; half = 0x400000 >> exp; /* add 0.5 to the magnitude and chop off the fraction bits */ return (x + half) & ~(0x7fffff >> exp); } int emulate_altivec(struct pt_regs *regs) { unsigned int instr, i; unsigned int va, vb, vc, vd; vector128 *vrs; if (get_user(instr, (unsigned int __user *) regs->nip)) return -EFAULT; if ((instr >> 26) != 4) return -EINVAL; /* not an altivec instruction */ vd = (instr >> 21) & 0x1f; va = (instr >> 16) & 0x1f; vb = (instr >> 11) & 0x1f; vc = (instr >> 6) & 0x1f; vrs = current->thread.vr; switch (instr & 0x3f) { case 10: switch (vc) { case 0: /* vaddfp */ vaddfp(&vrs[vd], &vrs[va], &vrs[vb]); break; case 1: /* vsubfp */ vsubfp(&vrs[vd], &vrs[va], &vrs[vb]); break; case 4: /* vrefp */ vrefp(&vrs[vd], &vrs[vb]); break; case 5: /* vrsqrtefp */ vrsqrtefp(&vrs[vd], &vrs[vb]); break; case 6: /* vexptefp */ for (i = 0; i < 4; ++i) vrs[vd].u[i] = eexp2(vrs[vb].u[i]); break; case 7: /* vlogefp */ for (i = 0; i < 4; ++i) vrs[vd].u[i] = elog2(vrs[vb].u[i]); break; case 8: /* vrfin */ for (i = 0; i < 4; ++i) vrs[vd].u[i] = rfin(vrs[vb].u[i]); break; case 9: /* vrfiz */ for (i = 0; i < 4; ++i) vrs[vd].u[i] = rfiz(vrs[vb].u[i]); break; case 10: /* vrfip */ for (i = 0; i < 4; ++i) { u32 x = vrs[vb].u[i]; x = (x & 0x80000000)? rfiz(x): rfii(x); vrs[vd].u[i] = x; } break; case 11: /* vrfim */ for (i = 0; i < 4; ++i) { u32 x = vrs[vb].u[i]; x = (x & 0x80000000)? rfii(x): rfiz(x); vrs[vd].u[i] = x; } break; case 14: /* vctuxs */ for (i = 0; i < 4; ++i) vrs[vd].u[i] = ctuxs(vrs[vb].u[i], va, ¤t->thread.vscr.u[3]); break; case 15: /* vctsxs */ for (i = 0; i < 4; ++i) vrs[vd].u[i] = ctsxs(vrs[vb].u[i], va, ¤t->thread.vscr.u[3]); break; default: return -EINVAL; } break; case 46: /* vmaddfp */ vmaddfp(&vrs[vd], &vrs[va], &vrs[vb], &vrs[vc]); break; case 47: /* vnmsubfp */ vnmsubfp(&vrs[vd], &vrs[va], &vrs[vb], &vrs[vc]); break; default: return -EINVAL; } return 0; } |