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   1 /*
   2  * cp1emu.c: a MIPS coprocessor 1 (fpu) instruction emulator
   3  *
   4  * MIPS floating point support
   5  * Copyright (C) 1994-2000 Algorithmics Ltd.
   6  * http://www.algor.co.uk
   7  *
   8  * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
   9  * Copyright (C) 2000  MIPS Technologies, Inc.
  10  *
  11  *  This program is free software; you can distribute it and/or modify it
  12  *  under the terms of the GNU General Public License (Version 2) as
  13  *  published by the Free Software Foundation.
  14  *
  15  *  This program is distributed in the hope it will be useful, but WITHOUT
  16  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  17  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  18  *  for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License along
  21  *  with this program; if not, write to the Free Software Foundation, Inc.,
  22  *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
  23  *
  24  * A complete emulator for MIPS coprocessor 1 instructions.  This is
  25  * required for #float(switch) or #float(trap), where it catches all
  26  * COP1 instructions via the "CoProcessor Unusable" exception.
  27  *
  28  * More surprisingly it is also required for #float(ieee), to help out
  29  * the hardware fpu at the boundaries of the IEEE-754 representation
  30  * (denormalised values, infinities, underflow, etc).  It is made
  31  * quite nasty because emulation of some non-COP1 instructions is
  32  * required, e.g. in branch delay slots.
  33  *
  34  * Note if you know that you won't have an fpu, then you'll get much
  35  * better performance by compiling with -msoft-float!
  36  */
  37 #include <linux/sched.h>
  38
  39 #include <asm/inst.h>
  40 #include <asm/bootinfo.h>
  41 #include <asm/cpu.h>
  42 #include <asm/cpu-features.h>
  43 #include <asm/processor.h>
  44 #include <asm/ptrace.h>
  45 #include <asm/signal.h>
  46 #include <asm/mipsregs.h>
  47 #include <asm/fpu_emulator.h>
  48 #include <asm/uaccess.h>
  49 #include <asm/branch.h>
  50
  51 #include "ieee754.h"
  52 #include "dsemul.h"
  53
  54 /* Strap kernel emulator for full MIPS IV emulation */
  55
  56 #ifdef __mips
  57 #undef __mips
  58 #endif
  59 #define __mips 4
  60
  61 /* Function which emulates a floating point instruction. */
  62
  63 static int fpu_emu(struct pt_regs *, struct mips_fpu_soft_struct *,
  64         mips_instruction);
  65
  66 #if __mips >= 4 && __mips != 32
  67 static int fpux_emu(struct pt_regs *,
  68         struct mips_fpu_soft_struct *, mips_instruction);
  69 #endif
  70
  71 /* Further private data for which no space exists in mips_fpu_soft_struct */
  72
  73 struct mips_fpu_emulator_stats fpuemustats;
  74
  75 /* Control registers */
  76
  77 #define FPCREG_RID      0       /* $0  = revision id */
  78 #define FPCREG_CSR      31      /* $31 = csr */
  79
  80 /* Convert Mips rounding mode (0..3) to IEEE library modes. */
  81 static const unsigned char ieee_rm[4] = {
  82         [FPU_CSR_RN] = IEEE754_RN,
  83         [FPU_CSR_RZ] = IEEE754_RZ,
  84         [FPU_CSR_RU] = IEEE754_RU,
  85         [FPU_CSR_RD] = IEEE754_RD,
  86 };
  87 /* Convert IEEE library modes to Mips rounding mode (0..3). */
  88 static const unsigned char mips_rm[4] = {
  89         [IEEE754_RN] = FPU_CSR_RN,
  90         [IEEE754_RZ] = FPU_CSR_RZ,
  91         [IEEE754_RD] = FPU_CSR_RD,
  92         [IEEE754_RU] = FPU_CSR_RU,
  93 };
  94
  95 #if __mips >= 4
  96 /* convert condition code register number to csr bit */
  97 static const unsigned int fpucondbit[8] = {
  98         FPU_CSR_COND0,
  99         FPU_CSR_COND1,
 100         FPU_CSR_COND2,
 101         FPU_CSR_COND3,
 102         FPU_CSR_COND4,
 103         FPU_CSR_COND5,
 104         FPU_CSR_COND6,
 105         FPU_CSR_COND7
 106 };
 107 #endif
 108
 109
 110 /*
 111  * Redundant with logic already in kernel/branch.c,
 112  * embedded in compute_return_epc.  At some point,
 113  * a single subroutine should be used across both
 114  * modules.
 115  */
 116 static int isBranchInstr(mips_instruction * i)
 117 {
 118         switch (MIPSInst_OPCODE(*i)) {
 119         case spec_op:
 120                 switch (MIPSInst_FUNC(*i)) {
 121                 case jalr_op:
 122                 case jr_op:
 123                         return 1;
 124                 }
 125                 break;
 126
 127         case bcond_op:
 128                 switch (MIPSInst_RT(*i)) {
 129                 case bltz_op:
 130                 case bgez_op:
 131                 case bltzl_op:
 132                 case bgezl_op:
 133                 case bltzal_op:
 134                 case bgezal_op:
 135                 case bltzall_op:
 136                 case bgezall_op:
 137                         return 1;
 138                 }
 139                 break;
 140
 141         case j_op:
 142         case jal_op:
 143         case jalx_op:
 144         case beq_op:
 145         case bne_op:
 146         case blez_op:
 147         case bgtz_op:
 148         case beql_op:
 149         case bnel_op:
 150         case blezl_op:
 151         case bgtzl_op:
 152                 return 1;
 153
 154         case cop0_op:
 155         case cop1_op:
 156         case cop2_op:
 157         case cop1x_op:
 158                 if (MIPSInst_RS(*i) == bc_op)
 159                         return 1;
 160                 break;
 161         }
 162
 163         return 0;
 164 }
 165
 166 /*
 167  * In the Linux kernel, we support selection of FPR format on the
 168  * basis of the Status.FR bit.  This does imply that, if a full 32
 169  * FPRs are desired, there needs to be a flip-flop that can be written
 170  * to one at that bit position.  In any case, O32 MIPS ABI uses
 171  * only the even FPRs (Status.FR = 0).
 172  */
 173
 174 #define CP0_STATUS_FR_SUPPORT
 175
 176 #ifdef CP0_STATUS_FR_SUPPORT
 177 #define FR_BIT ST0_FR
 178 #else
 179 #define FR_BIT 0
 180 #endif
 181
 182 #define SIFROMREG(si,x) ((si) = \
 183                         (xcp->cp0_status & FR_BIT) || !(x & 1) ? \
 184                         (int)ctx->fpr[x] : \
 185                         (int)(ctx->fpr[x & ~1] >> 32 ))
 186 #define SITOREG(si,x)   (ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)] = \
 187                         (xcp->cp0_status & FR_BIT) || !(x & 1) ? \
 188                         ctx->fpr[x & ~1] >> 32 << 32 | (u32)(si) : \
 189                         ctx->fpr[x & ~1] << 32 >> 32 | (u64)(si) << 32)
 190
 191 #define DIFROMREG(di,x) ((di) = \
 192                         ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)])
 193 #define DITOREG(di,x)   (ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)] \
 194                         = (di))
 195
 196 #define SPFROMREG(sp,x) SIFROMREG((sp).bits,x)
 197 #define SPTOREG(sp,x)   SITOREG((sp).bits,x)
 198 #define DPFROMREG(dp,x) DIFROMREG((dp).bits,x)
 199 #define DPTOREG(dp,x)   DITOREG((dp).bits,x)
 200
 201 /*
 202  * Emulate the single floating point instruction pointed at by EPC.
 203  * Two instructions if the instruction is in a branch delay slot.
 204  */
 205
 206 static int cop1Emulate(struct pt_regs *xcp, struct mips_fpu_soft_struct *ctx)
 207 {
 208         mips_instruction ir;
 209         void * emulpc, *contpc;
 210         unsigned int cond;
 211
 212         if (get_user(ir, (mips_instruction *) xcp->cp0_epc)) {
 213                 fpuemustats.errors++;
 214                 return SIGBUS;
 215         }
 216
 217         /* XXX NEC Vr54xx bug workaround */
 218         if ((xcp->cp0_cause & CAUSEF_BD) && !isBranchInstr(&ir))
 219                 xcp->cp0_cause &= ~CAUSEF_BD;
 220
 221         if (xcp->cp0_cause & CAUSEF_BD) {
 222                 /*
 223                  * The instruction to be emulated is in a branch delay slot
 224                  * which means that we have to  emulate the branch instruction
 225                  * BEFORE we do the cop1 instruction.
 226                  *
 227                  * This branch could be a COP1 branch, but in that case we
 228                  * would have had a trap for that instruction, and would not
 229                  * come through this route.
 230                  *
 231                  * Linux MIPS branch emulator operates on context, updating the
 232                  * cp0_epc.
 233                  */
 234                 emulpc = (void *) (xcp->cp0_epc + 4);   /* Snapshot emulation target */
 235
 236                 if (__compute_return_epc(xcp)) {
 237 #ifdef CP1DBG
 238                         printk("failed to emulate branch at %p\n",
 239                                 (void *) (xcp->cp0_epc));
 240 #endif
 241                         return SIGILL;
 242                 }
 243                 if (get_user(ir, (mips_instruction *) emulpc)) {
 244                         fpuemustats.errors++;
 245                         return SIGBUS;
 246                 }
 247                 /* __compute_return_epc() will have updated cp0_epc */
 248                 contpc = (void *)  xcp->cp0_epc;
 249                 /* In order not to confuse ptrace() et al, tweak context */
 250                 xcp->cp0_epc = (unsigned long) emulpc - 4;
 251         } else {
 252                 emulpc = (void *)  xcp->cp0_epc;
 253                 contpc = (void *) (xcp->cp0_epc + 4);
 254         }
 255
 256       emul:
 257         fpuemustats.emulated++;
 258         switch (MIPSInst_OPCODE(ir)) {
 259 #ifndef SINGLE_ONLY_FPU
 260         case ldc1_op:{
 261                 u64 *va = (void *) (xcp->regs[MIPSInst_RS(ir)] +
 262                         MIPSInst_SIMM(ir));
 263                 u64 val;
 264
 265                 fpuemustats.loads++;
 266                 if (get_user(val, va)) {
 267                         fpuemustats.errors++;
 268                         return SIGBUS;
 269                 }
 270                 DITOREG(val, MIPSInst_RT(ir));
 271                 break;
 272         }
 273
 274         case sdc1_op:{
 275                 u64 *va = (void *) (xcp->regs[MIPSInst_RS(ir)] +
 276                         MIPSInst_SIMM(ir));
 277                 u64 val;
 278
 279                 fpuemustats.stores++;
 280                 DIFROMREG(val, MIPSInst_RT(ir));
 281                 if (put_user(val, va)) {
 282                         fpuemustats.errors++;
 283                         return SIGBUS;
 284                 }
 285                 break;
 286         }
 287 #endif
 288
 289         case lwc1_op:{
 290                 u32 *va = (void *) (xcp->regs[MIPSInst_RS(ir)] +
 291                         MIPSInst_SIMM(ir));
 292                 u32 val;
 293
 294                 fpuemustats.loads++;
 295                 if (get_user(val, va)) {
 296                         fpuemustats.errors++;
 297                         return SIGBUS;
 298                 }
 299 #ifdef SINGLE_ONLY_FPU
 300                 if (MIPSInst_RT(ir) & 1) {
 301                         /* illegal register in single-float mode */
 302                         return SIGILL;
 303                 }
 304 #endif
 305                 SITOREG(val, MIPSInst_RT(ir));
 306                 break;
 307         }
 308
 309         case swc1_op:{
 310                 u32 *va = (void *) (xcp->regs[MIPSInst_RS(ir)] +
 311                         MIPSInst_SIMM(ir));
 312                 u32 val;
 313
 314                 fpuemustats.stores++;
 315 #ifdef SINGLE_ONLY_FPU
 316                 if (MIPSInst_RT(ir) & 1) {
 317                         /* illegal register in single-float mode */
 318                         return SIGILL;
 319                 }
 320 #endif
 321                 SIFROMREG(val, MIPSInst_RT(ir));
 322                 if (put_user(val, va)) {
 323                         fpuemustats.errors++;
 324                         return SIGBUS;
 325                 }
 326                 break;
 327         }
 328
 329         case cop1_op:
 330                 switch (MIPSInst_RS(ir)) {
 331
 332 #if defined(__mips64) && !defined(SINGLE_ONLY_FPU)
 333                 case dmfc_op:
 334                         /* copregister fs -> gpr[rt] */
 335                         if (MIPSInst_RT(ir) != 0) {
 336                                 DIFROMREG(xcp->regs[MIPSInst_RT(ir)],
 337                                         MIPSInst_RD(ir));
 338                         }
 339                         break;
 340
 341                 case dmtc_op:
 342                         /* copregister fs <- rt */
 343                         DITOREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir));
 344                         break;
 345 #endif
 346
 347                 case mfc_op:
 348                         /* copregister rd -> gpr[rt] */
 349 #ifdef SINGLE_ONLY_FPU
 350                         if (MIPSInst_RD(ir) & 1) {
 351                                 /* illegal register in single-float mode */
 352                                 return SIGILL;
 353                         }
 354 #endif
 355                         if (MIPSInst_RT(ir) != 0) {
 356                                 SIFROMREG(xcp->regs[MIPSInst_RT(ir)],
 357                                         MIPSInst_RD(ir));
 358                         }
 359                         break;
 360
 361                 case mtc_op:
 362                         /* copregister rd <- rt */
 363 #ifdef SINGLE_ONLY_FPU
 364                         if (MIPSInst_RD(ir) & 1) {
 365                                 /* illegal register in single-float mode */
 366                                 return SIGILL;
 367                         }
 368 #endif
 369                         SITOREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir));
 370                         break;
 371
 372                 case cfc_op:{
 373                         /* cop control register rd -> gpr[rt] */
 374                         u32 value;
 375
 376                         if (ir == CP1UNDEF) {
 377                                 return do_dsemulret(xcp);
 378                         }
 379                         if (MIPSInst_RD(ir) == FPCREG_CSR) {
 380                                 value = ctx->fcr31;
 381                                 value = (value & ~0x3) | mips_rm[value & 0x3];
 382 #ifdef CSRTRACE
 383                                 printk("%p gpr[%d]<-csr=%08x\n",
 384                                         (void *) (xcp->cp0_epc),
 385                                         MIPSInst_RT(ir), value);
 386 #endif
 387                         }
 388                         else if (MIPSInst_RD(ir) == FPCREG_RID)
 389                                 value = 0;
 390                         else
 391                                 value = 0;
 392                         if (MIPSInst_RT(ir))
 393                                 xcp->regs[MIPSInst_RT(ir)] = value;
 394                         break;
 395                 }
 396
 397                 case ctc_op:{
 398                         /* copregister rd <- rt */
 399                         u32 value;
 400
 401                         if (MIPSInst_RT(ir) == 0)
 402                                 value = 0;
 403                         else
 404                                 value = xcp->regs[MIPSInst_RT(ir)];
 405
 406                         /* we only have one writable control reg
 407                          */
 408                         if (MIPSInst_RD(ir) == FPCREG_CSR) {
 409 #ifdef CSRTRACE
 410                                 printk("%p gpr[%d]->csr=%08x\n",
 411                                         (void *) (xcp->cp0_epc),
 412                                         MIPSInst_RT(ir), value);
 413 #endif
 414                                 value &= (FPU_CSR_FLUSH | FPU_CSR_ALL_E | FPU_CSR_ALL_S | 0x03);
 415                                 ctx->fcr31 &= ~(FPU_CSR_FLUSH | FPU_CSR_ALL_E | FPU_CSR_ALL_S | 0x03);
 416                                 /* convert to ieee library modes */
 417                                 ctx->fcr31 |= (value & ~0x3) | ieee_rm[value & 0x3];
 418                         }
 419                         if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
 420                                 return SIGFPE;
 421                         }
 422                         break;
 423                 }
 424
 425                 case bc_op:{
 426                         int likely = 0;
 427
 428                         if (xcp->cp0_cause & CAUSEF_BD)
 429                                 return SIGILL;
 430
 431 #if __mips >= 4
 432                         cond = ctx->fcr31 & fpucondbit[MIPSInst_RT(ir) >> 2];
 433 #else
 434                         cond = ctx->fcr31 & FPU_CSR_COND;
 435 #endif
 436                         switch (MIPSInst_RT(ir) & 3) {
 437                         case bcfl_op:
 438                                 likely = 1;
 439                         case bcf_op:
 440                                 cond = !cond;
 441                                 break;
 442                         case bctl_op:
 443                                 likely = 1;
 444                         case bct_op:
 445                                 break;
 446                         default:
 447                                 /* thats an illegal instruction */
 448                                 return SIGILL;
 449                         }
 450
 451                         xcp->cp0_cause |= CAUSEF_BD;
 452                         if (cond) {
 453                                 /* branch taken: emulate dslot
 454                                  * instruction
 455                                  */
 456                                 xcp->cp0_epc += 4;
 457                                 contpc = (void *)
 458                                         (xcp->cp0_epc +
 459                                         (MIPSInst_SIMM(ir) << 2));
 460
 461                                 if (get_user(ir, (mips_instruction *)
 462                                                 (void *)  xcp->cp0_epc)) {
 463                                         fpuemustats.errors++;
 464                                         return SIGBUS;
 465                                 }
 466
 467                                 switch (MIPSInst_OPCODE(ir)) {
 468                                 case lwc1_op:
 469                                 case swc1_op:
 470 #if (__mips >= 2 || defined(__mips64)) && !defined(SINGLE_ONLY_FPU)
 471                                 case ldc1_op:
 472                                 case sdc1_op:
 473 #endif
 474                                 case cop1_op:
 475 #if __mips >= 4 && __mips != 32
 476                                 case cop1x_op:
 477 #endif
 478                                         /* its one of ours */
 479                                         goto emul;
 480 #if __mips >= 4
 481                                 case spec_op:
 482                                         if (MIPSInst_FUNC(ir) == movc_op)
 483                                                 goto emul;
 484                                         break;
 485 #endif
 486                                 }
 487
 488                                 /*
 489                                  * Single step the non-cp1
 490                                  * instruction in the dslot
 491                                  */
 492                                 return mips_dsemul(xcp, ir, (unsigned long) contpc);
 493                         }
 494                         else {
 495                                 /* branch not taken */
 496                                 if (likely) {
 497                                         /*
 498                                          * branch likely nullifies
 499                                          * dslot if not taken
 500                                          */
 501                                         xcp->cp0_epc += 4;
 502                                         contpc += 4;
 503                                         /*
 504                                          * else continue & execute
 505                                          * dslot as normal insn
 506                                          */
 507                                 }
 508                         }
 509                         break;
 510                 }
 511
 512                 default:
 513                         if (!(MIPSInst_RS(ir) & 0x10))
 514                                 return SIGILL;
 515                         {
 516                                 int sig;
 517
 518                                 /* a real fpu computation instruction */
 519                                 if ((sig = fpu_emu(xcp, ctx, ir)))
 520                                         return sig;
 521                         }
 522                 }
 523                 break;
 524
 525 #if __mips >= 4 && __mips != 32
 526         case cop1x_op:{
 527                 int sig;
 528
 529                 if ((sig = fpux_emu(xcp, ctx, ir)))
 530                         return sig;
 531                 break;
 532         }
 533 #endif
 534
 535 #if __mips >= 4
 536         case spec_op:
 537                 if (MIPSInst_FUNC(ir) != movc_op)
 538                         return SIGILL;
 539                 cond = fpucondbit[MIPSInst_RT(ir) >> 2];
 540                 if (((ctx->fcr31 & cond) != 0) == ((MIPSInst_RT(ir) & 1) != 0))
 541                         xcp->regs[MIPSInst_RD(ir)] =
 542                                 xcp->regs[MIPSInst_RS(ir)];
 543                 break;
 544 #endif
 545
 546         default:
 547                 return SIGILL;
 548         }
 549
 550         /* we did it !! */
 551         xcp->cp0_epc = (unsigned long) contpc;
 552         xcp->cp0_cause &= ~CAUSEF_BD;
 553
 554         return 0;
 555 }
 556
 557 /*
 558  * Conversion table from MIPS compare ops 48-63
 559  * cond = ieee754dp_cmp(x,y,IEEE754_UN,sig);
 560  */
 561 static const unsigned char cmptab[8] = {
 562         0,                      /* cmp_0 (sig) cmp_sf */
 563         IEEE754_CUN,            /* cmp_un (sig) cmp_ngle */
 564         IEEE754_CEQ,            /* cmp_eq (sig) cmp_seq */
 565         IEEE754_CEQ | IEEE754_CUN,      /* cmp_ueq (sig) cmp_ngl  */
 566         IEEE754_CLT,            /* cmp_olt (sig) cmp_lt */
 567         IEEE754_CLT | IEEE754_CUN,      /* cmp_ult (sig) cmp_nge */
 568         IEEE754_CLT | IEEE754_CEQ,      /* cmp_ole (sig) cmp_le */
 569         IEEE754_CLT | IEEE754_CEQ | IEEE754_CUN,        /* cmp_ule (sig) cmp_ngt */
 570 };
 571
 572
 573 #if __mips >= 4 && __mips != 32
 574
 575 /*
 576  * Additional MIPS4 instructions
 577  */
 578
 579 #define DEF3OP(name, p, f1, f2, f3) \
 580 static ieee754##p fpemu_##p##_##name (ieee754##p r, ieee754##p s, \
 581     ieee754##p t) \
 582 { \
 583         struct _ieee754_csr ieee754_csr_save; \
 584         s = f1 (s, t); \
 585         ieee754_csr_save = ieee754_csr; \
 586         s = f2 (s, r); \
 587         ieee754_csr_save.cx |= ieee754_csr.cx; \
 588         ieee754_csr_save.sx |= ieee754_csr.sx; \
 589         s = f3 (s); \
 590         ieee754_csr.cx |= ieee754_csr_save.cx; \
 591         ieee754_csr.sx |= ieee754_csr_save.sx; \
 592         return s; \
 593 }
 594
 595 static ieee754dp fpemu_dp_recip(ieee754dp d)
 596 {
 597         return ieee754dp_div(ieee754dp_one(0), d);
 598 }
 599
 600 static ieee754dp fpemu_dp_rsqrt(ieee754dp d)
 601 {
 602         return ieee754dp_div(ieee754dp_one(0), ieee754dp_sqrt(d));
 603 }
 604
 605 static ieee754sp fpemu_sp_recip(ieee754sp s)
 606 {
 607         return ieee754sp_div(ieee754sp_one(0), s);
 608 }
 609
 610 static ieee754sp fpemu_sp_rsqrt(ieee754sp s)
 611 {
 612         return ieee754sp_div(ieee754sp_one(0), ieee754sp_sqrt(s));
 613 }
 614
 615 DEF3OP(madd, sp, ieee754sp_mul, ieee754sp_add,);
 616 DEF3OP(msub, sp, ieee754sp_mul, ieee754sp_sub,);
 617 DEF3OP(nmadd, sp, ieee754sp_mul, ieee754sp_add, ieee754sp_neg);
 618 DEF3OP(nmsub, sp, ieee754sp_mul, ieee754sp_sub, ieee754sp_neg);
 619 DEF3OP(madd, dp, ieee754dp_mul, ieee754dp_add,);
 620 DEF3OP(msub, dp, ieee754dp_mul, ieee754dp_sub,);
 621 DEF3OP(nmadd, dp, ieee754dp_mul, ieee754dp_add, ieee754dp_neg);
 622 DEF3OP(nmsub, dp, ieee754dp_mul, ieee754dp_sub, ieee754dp_neg);
 623
 624 static int fpux_emu(struct pt_regs *xcp, struct mips_fpu_soft_struct *ctx,
 625         mips_instruction ir)
 626 {
 627         unsigned rcsr = 0;      /* resulting csr */
 628
 629         fpuemustats.cp1xops++;
 630
 631         switch (MIPSInst_FMA_FFMT(ir)) {
 632         case s_fmt:{            /* 0 */
 633
 634                 ieee754sp(*handler) (ieee754sp, ieee754sp, ieee754sp);
 635                 ieee754sp fd, fr, fs, ft;
 636                 u32 *va;
 637                 u32 val;
 638
 639                 switch (MIPSInst_FUNC(ir)) {
 640                 case lwxc1_op:
 641                         va = (void *) (xcp->regs[MIPSInst_FR(ir)] +
 642                                 xcp->regs[MIPSInst_FT(ir)]);
 643
 644                         fpuemustats.loads++;
 645                         if (get_user(val, va)) {
 646                                 fpuemustats.errors++;
 647                                 return SIGBUS;
 648                         }
 649 #ifdef SINGLE_ONLY_FPU
 650                         if (MIPSInst_FD(ir) & 1) {
 651                                 /* illegal register in single-float
 652                                  * mode
 653                                  */
 654                                 return SIGILL;
 655                         }
 656 #endif
 657                         SITOREG(val, MIPSInst_FD(ir));
 658                         break;
 659
 660                 case swxc1_op:
 661                         va = (void *) (xcp->regs[MIPSInst_FR(ir)] +
 662                                 xcp->regs[MIPSInst_FT(ir)]);
 663
 664                         fpuemustats.stores++;
 665 #ifdef SINGLE_ONLY_FPU
 666                         if (MIPSInst_FS(ir) & 1) {
 667                                 /* illegal register in single-float
 668                                  * mode
 669                                  */
 670                                 return SIGILL;
 671                         }
 672 #endif
 673
 674                         SIFROMREG(val, MIPSInst_FS(ir));
 675                         if (put_user(val, va)) {
 676                                 fpuemustats.errors++;
 677                                 return SIGBUS;
 678                         }
 679                         break;
 680
 681                 case madd_s_op:
 682                         handler = fpemu_sp_madd;
 683                         goto scoptop;
 684                 case msub_s_op:
 685                         handler = fpemu_sp_msub;
 686                         goto scoptop;
 687                 case nmadd_s_op:
 688                         handler = fpemu_sp_nmadd;
 689                         goto scoptop;
 690                 case nmsub_s_op:
 691                         handler = fpemu_sp_nmsub;
 692                         goto scoptop;
 693
 694                       scoptop:
 695                         SPFROMREG(fr, MIPSInst_FR(ir));
 696                         SPFROMREG(fs, MIPSInst_FS(ir));
 697                         SPFROMREG(ft, MIPSInst_FT(ir));
 698                         fd = (*handler) (fr, fs, ft);
 699                         SPTOREG(fd, MIPSInst_FD(ir));
 700
 701                       copcsr:
 702                         if (ieee754_cxtest(IEEE754_INEXACT))
 703                                 rcsr |= FPU_CSR_INE_X | FPU_CSR_INE_S;
 704                         if (ieee754_cxtest(IEEE754_UNDERFLOW))
 705                                 rcsr |= FPU_CSR_UDF_X | FPU_CSR_UDF_S;
 706                         if (ieee754_cxtest(IEEE754_OVERFLOW))
 707                                 rcsr |= FPU_CSR_OVF_X | FPU_CSR_OVF_S;
 708                         if (ieee754_cxtest(IEEE754_INVALID_OPERATION))
 709                                 rcsr |= FPU_CSR_INV_X | FPU_CSR_INV_S;
 710
 711                         ctx->fcr31 = (ctx->fcr31 & ~FPU_CSR_ALL_X) | rcsr;
 712                         if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
 713                                 /*printk ("SIGFPE: fpu csr = %08x\n",
 714                                    ctx->fcr31); */
 715                                 return SIGFPE;
 716                         }
 717
 718                         break;
 719
 720                 default:
 721                         return SIGILL;
 722                 }
 723                 break;
 724         }
 725
 726 #ifndef SINGLE_ONLY_FPU
 727         case d_fmt:{            /* 1 */
 728                 ieee754dp(*handler) (ieee754dp, ieee754dp, ieee754dp);
 729                 ieee754dp fd, fr, fs, ft;
 730                 u64 *va;
 731                 u64 val;
 732
 733                 switch (MIPSInst_FUNC(ir)) {
 734                 case ldxc1_op:
 735                         va = (void *) (xcp->regs[MIPSInst_FR(ir)] +
 736                                 xcp->regs[MIPSInst_FT(ir)]);
 737
 738                         fpuemustats.loads++;
 739                         if (get_user(val, va)) {
 740                                 fpuemustats.errors++;
 741                                 return SIGBUS;
 742                         }
 743                         DITOREG(val, MIPSInst_FD(ir));
 744                         break;
 745
 746                 case sdxc1_op:
 747                         va = (void *) (xcp->regs[MIPSInst_FR(ir)] +
 748                                 xcp->regs[MIPSInst_FT(ir)]);
 749
 750                         fpuemustats.stores++;
 751                         DIFROMREG(val, MIPSInst_FS(ir));
 752                         if (put_user(val, va)) {
 753                                 fpuemustats.errors++;
 754                                 return SIGBUS;
 755                         }
 756                         break;
 757
 758                 case madd_d_op:
 759                         handler = fpemu_dp_madd;
 760                         goto dcoptop;
 761                 case msub_d_op:
 762                         handler = fpemu_dp_msub;
 763                         goto dcoptop;
 764                 case nmadd_d_op:
 765                         handler = fpemu_dp_nmadd;
 766                         goto dcoptop;
 767                 case nmsub_d_op:
 768                         handler = fpemu_dp_nmsub;
 769                         goto dcoptop;
 770
 771                       dcoptop:
 772                         DPFROMREG(fr, MIPSInst_FR(ir));
 773                         DPFROMREG(fs, MIPSInst_FS(ir));
 774                         DPFROMREG(ft, MIPSInst_FT(ir));
 775                         fd = (*handler) (fr, fs, ft);
 776                         DPTOREG(fd, MIPSInst_FD(ir));
 777                         goto copcsr;
 778
 779                 default:
 780                         return SIGILL;
 781                 }
 782                 break;
 783         }
 784 #endif
 785
 786         case 0x7:               /* 7 */
 787                 if (MIPSInst_FUNC(ir) != pfetch_op) {
 788                         return SIGILL;
 789                 }
 790                 /* ignore prefx operation */
 791                 break;
 792
 793         default:
 794                 return SIGILL;
 795         }
 796
 797         return 0;
 798 }
 799 #endif
 800
 801
 802
 803 /*
 804  * Emulate a single COP1 arithmetic instruction.
 805  */
 806 static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_soft_struct *ctx,
 807         mips_instruction ir)
 808 {
 809         int rfmt;               /* resulting format */
 810         unsigned rcsr = 0;      /* resulting csr */
 811         unsigned cond;
 812         union {
 813                 ieee754dp d;
 814                 ieee754sp s;
 815                 int w;
 816 #ifdef __mips64
 817                 s64 l;
 818 #endif
 819         } rv;                   /* resulting value */
 820
 821         fpuemustats.cp1ops++;
 822         switch (rfmt = (MIPSInst_FFMT(ir) & 0xf)) {
 823         case s_fmt:{            /* 0 */
 824                 union {
 825                         ieee754sp(*b) (ieee754sp, ieee754sp);
 826                         ieee754sp(*u) (ieee754sp);
 827                 } handler;
 828
 829                 switch (MIPSInst_FUNC(ir)) {
 830                         /* binary ops */
 831                 case fadd_op:
 832                         handler.b = ieee754sp_add;
 833                         goto scopbop;
 834                 case fsub_op:
 835                         handler.b = ieee754sp_sub;
 836                         goto scopbop;
 837                 case fmul_op:
 838                         handler.b = ieee754sp_mul;
 839                         goto scopbop;
 840                 case fdiv_op:
 841                         handler.b = ieee754sp_div;
 842                         goto scopbop;
 843
 844                         /* unary  ops */
 845 #if __mips >= 2 || defined(__mips64)
 846                 case fsqrt_op:
 847                         handler.u = ieee754sp_sqrt;
 848                         goto scopuop;
 849 #endif
 850 #if __mips >= 4 && __mips != 32
 851                 case frsqrt_op:
 852                         handler.u = fpemu_sp_rsqrt;
 853                         goto scopuop;
 854                 case frecip_op:
 855                         handler.u = fpemu_sp_recip;
 856                         goto scopuop;
 857 #endif
 858 #if __mips >= 4
 859                 case fmovc_op:
 860                         cond = fpucondbit[MIPSInst_FT(ir) >> 2];
 861                         if (((ctx->fcr31 & cond) != 0) !=
 862                                 ((MIPSInst_FT(ir) & 1) != 0))
 863                                 return 0;
 864                         SPFROMREG(rv.s, MIPSInst_FS(ir));
 865                         break;
 866                 case fmovz_op:
 867                         if (xcp->regs[MIPSInst_FT(ir)] != 0)
 868                                 return 0;
 869                         SPFROMREG(rv.s, MIPSInst_FS(ir));
 870                         break;
 871                 case fmovn_op:
 872                         if (xcp->regs[MIPSInst_FT(ir)] == 0)
 873                                 return 0;
 874                         SPFROMREG(rv.s, MIPSInst_FS(ir));
 875                         break;
 876 #endif
 877                 case fabs_op:
 878                         handler.u = ieee754sp_abs;
 879                         goto scopuop;
 880                 case fneg_op:
 881                         handler.u = ieee754sp_neg;
 882                         goto scopuop;
 883                 case fmov_op:
 884                         /* an easy one */
 885                         SPFROMREG(rv.s, MIPSInst_FS(ir));
 886                         goto copcsr;
 887
 888                         /* binary op on handler */
 889                       scopbop:
 890                         {
 891                                 ieee754sp fs, ft;
 892
 893                                 SPFROMREG(fs, MIPSInst_FS(ir));
 894                                 SPFROMREG(ft, MIPSInst_FT(ir));
 895
 896                                 rv.s = (*handler.b) (fs, ft);
 897                                 goto copcsr;
 898                         }
 899                       scopuop:
 900                         {
 901                                 ieee754sp fs;
 902
 903                                 SPFROMREG(fs, MIPSInst_FS(ir));
 904                                 rv.s = (*handler.u) (fs);
 905                                 goto copcsr;
 906                         }
 907                       copcsr:
 908                         if (ieee754_cxtest(IEEE754_INEXACT))
 909                                 rcsr |= FPU_CSR_INE_X | FPU_CSR_INE_S;
 910                         if (ieee754_cxtest(IEEE754_UNDERFLOW))
 911                                 rcsr |= FPU_CSR_UDF_X | FPU_CSR_UDF_S;
 912                         if (ieee754_cxtest(IEEE754_OVERFLOW))
 913                                 rcsr |= FPU_CSR_OVF_X | FPU_CSR_OVF_S;
 914                         if (ieee754_cxtest(IEEE754_ZERO_DIVIDE))
 915                                 rcsr |= FPU_CSR_DIV_X | FPU_CSR_DIV_S;
 916                         if (ieee754_cxtest(IEEE754_INVALID_OPERATION))
 917                                 rcsr |= FPU_CSR_INV_X | FPU_CSR_INV_S;
 918                         break;
 919
 920                         /* unary conv ops */
 921                 case fcvts_op:
 922                         return SIGILL;  /* not defined */
 923                 case fcvtd_op:{
 924 #ifdef SINGLE_ONLY_FPU
 925                         return SIGILL;  /* not defined */
 926 #else
 927                         ieee754sp fs;
 928
 929                         SPFROMREG(fs, MIPSInst_FS(ir));
 930                         rv.d = ieee754dp_fsp(fs);
 931                         rfmt = d_fmt;
 932                         goto copcsr;
 933                 }
 934 #endif
 935                 case fcvtw_op:{
 936                         ieee754sp fs;
 937
 938                         SPFROMREG(fs, MIPSInst_FS(ir));
 939                         rv.w = ieee754sp_tint(fs);
 940                         rfmt = w_fmt;
 941                         goto copcsr;
 942                 }
 943
 944 #if __mips >= 2 || defined(__mips64)
 945                 case fround_op:
 946                 case ftrunc_op:
 947                 case fceil_op:
 948                 case ffloor_op:{
 949                         unsigned int oldrm = ieee754_csr.rm;
 950                         ieee754sp fs;
 951
 952                         SPFROMREG(fs, MIPSInst_FS(ir));
 953                         ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
 954                         rv.w = ieee754sp_tint(fs);
 955                         ieee754_csr.rm = oldrm;
 956                         rfmt = w_fmt;
 957                         goto copcsr;
 958                 }
 959 #endif /* __mips >= 2 */
 960
 961 #if defined(__mips64) && !defined(SINGLE_ONLY_FPU)
 962                 case fcvtl_op:{
 963                         ieee754sp fs;
 964
 965                         SPFROMREG(fs, MIPSInst_FS(ir));
 966                         rv.l = ieee754sp_tlong(fs);
 967                         rfmt = l_fmt;
 968                         goto copcsr;
 969                 }
 970
 971                 case froundl_op:
 972                 case ftruncl_op:
 973                 case fceill_op:
 974                 case ffloorl_op:{
 975                         unsigned int oldrm = ieee754_csr.rm;
 976                         ieee754sp fs;
 977
 978                         SPFROMREG(fs, MIPSInst_FS(ir));
 979                         ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
 980                         rv.l = ieee754sp_tlong(fs);
 981                         ieee754_csr.rm = oldrm;
 982                         rfmt = l_fmt;
 983                         goto copcsr;
 984                 }
 985 #endif /* defined(__mips64) && !fpu(single) */
 986
 987                 default:
 988                         if (MIPSInst_FUNC(ir) >= fcmp_op) {
 989                                 unsigned cmpop = MIPSInst_FUNC(ir) - fcmp_op;
 990                                 ieee754sp fs, ft;
 991
 992                                 SPFROMREG(fs, MIPSInst_FS(ir));
 993                                 SPFROMREG(ft, MIPSInst_FT(ir));
 994                                 rv.w = ieee754sp_cmp(fs, ft,
 995                                         cmptab[cmpop & 0x7], cmpop & 0x8);
 996                                 rfmt = -1;
 997                                 if ((cmpop & 0x8) && ieee754_cxtest
 998                                         (IEEE754_INVALID_OPERATION))
 999                                         rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
1000                                 else
1001                                         goto copcsr;
1002
1003                         }
1004                         else {
1005                                 return SIGILL;
1006                         }
1007                         break;
1008                 }
1009                 break;
1010         }
1011
1012 #ifndef SINGLE_ONLY_FPU
1013         case d_fmt:{
1014                 union {
1015                         ieee754dp(*b) (ieee754dp, ieee754dp);
1016                         ieee754dp(*u) (ieee754dp);
1017                 } handler;
1018
1019                 switch (MIPSInst_FUNC(ir)) {
1020                         /* binary ops */
1021                 case fadd_op:
1022                         handler.b = ieee754dp_add;
1023                         goto dcopbop;
1024                 case fsub_op:
1025                         handler.b = ieee754dp_sub;
1026                         goto dcopbop;
1027                 case fmul_op:
1028                         handler.b = ieee754dp_mul;
1029                         goto dcopbop;
1030                 case fdiv_op:
1031                         handler.b = ieee754dp_div;
1032                         goto dcopbop;
1033
1034                         /* unary  ops */
1035 #if __mips >= 2 || defined(__mips64)
1036                 case fsqrt_op:
1037                         handler.u = ieee754dp_sqrt;
1038                         goto dcopuop;
1039 #endif
1040 #if __mips >= 4 && __mips != 32
1041                 case frsqrt_op:
1042                         handler.u = fpemu_dp_rsqrt;
1043                         goto dcopuop;
1044                 case frecip_op:
1045                         handler.u = fpemu_dp_recip;
1046                         goto dcopuop;
1047 #endif
1048 #if __mips >= 4
1049                 case fmovc_op:
1050                         cond = fpucondbit[MIPSInst_FT(ir) >> 2];
1051                         if (((ctx->fcr31 & cond) != 0) !=
1052                                 ((MIPSInst_FT(ir) & 1) != 0))
1053                                 return 0;
1054                         DPFROMREG(rv.d, MIPSInst_FS(ir));
1055                         break;
1056                 case fmovz_op:
1057                         if (xcp->regs[MIPSInst_FT(ir)] != 0)
1058                                 return 0;
1059                         DPFROMREG(rv.d, MIPSInst_FS(ir));
1060                         break;
1061                 case fmovn_op:
1062                         if (xcp->regs[MIPSInst_FT(ir)] == 0)
1063                                 return 0;
1064                         DPFROMREG(rv.d, MIPSInst_FS(ir));
1065                         break;
1066 #endif
1067                 case fabs_op:
1068                         handler.u = ieee754dp_abs;
1069                         goto dcopuop;
1070
1071                 case fneg_op:
1072                         handler.u = ieee754dp_neg;
1073                         goto dcopuop;
1074
1075                 case fmov_op:
1076                         /* an easy one */
1077                         DPFROMREG(rv.d, MIPSInst_FS(ir));
1078                         goto copcsr;
1079
1080                         /* binary op on handler */
1081                       dcopbop:{
1082                                 ieee754dp fs, ft;
1083
1084                                 DPFROMREG(fs, MIPSInst_FS(ir));
1085                                 DPFROMREG(ft, MIPSInst_FT(ir));
1086
1087                                 rv.d = (*handler.b) (fs, ft);
1088                                 goto copcsr;
1089                         }
1090                       dcopuop:{
1091                                 ieee754dp fs;
1092
1093                                 DPFROMREG(fs, MIPSInst_FS(ir));
1094                                 rv.d = (*handler.u) (fs);
1095                                 goto copcsr;
1096                         }
1097
1098                         /* unary conv ops */
1099                 case fcvts_op:{
1100                         ieee754dp fs;
1101
1102                         DPFROMREG(fs, MIPSInst_FS(ir));
1103                         rv.s = ieee754sp_fdp(fs);
1104                         rfmt = s_fmt;
1105                         goto copcsr;
1106                 }
1107                 case fcvtd_op:
1108                         return SIGILL;  /* not defined */
1109
1110                 case fcvtw_op:{
1111                         ieee754dp fs;
1112
1113                         DPFROMREG(fs, MIPSInst_FS(ir));
1114                         rv.w = ieee754dp_tint(fs);      /* wrong */
1115                         rfmt = w_fmt;
1116                         goto copcsr;
1117                 }
1118
1119 #if __mips >= 2 || defined(__mips64)
1120                 case fround_op:
1121                 case ftrunc_op:
1122                 case fceil_op:
1123                 case ffloor_op:{
1124                         unsigned int oldrm = ieee754_csr.rm;
1125                         ieee754dp fs;
1126
1127                         DPFROMREG(fs, MIPSInst_FS(ir));
1128                         ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
1129                         rv.w = ieee754dp_tint(fs);
1130                         ieee754_csr.rm = oldrm;
1131                         rfmt = w_fmt;
1132                         goto copcsr;
1133                 }
1134 #endif
1135
1136 #if defined(__mips64) && !defined(SINGLE_ONLY_FPU)
1137                 case fcvtl_op:{
1138                         ieee754dp fs;
1139
1140                         DPFROMREG(fs, MIPSInst_FS(ir));
1141                         rv.l = ieee754dp_tlong(fs);
1142                         rfmt = l_fmt;
1143                         goto copcsr;
1144                 }
1145
1146                 case froundl_op:
1147                 case ftruncl_op:
1148                 case fceill_op:
1149                 case ffloorl_op:{
1150                         unsigned int oldrm = ieee754_csr.rm;
1151                         ieee754dp fs;
1152
1153                         DPFROMREG(fs, MIPSInst_FS(ir));
1154                         ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
1155                         rv.l = ieee754dp_tlong(fs);
1156                         ieee754_csr.rm = oldrm;
1157                         rfmt = l_fmt;
1158                         goto copcsr;
1159                 }
1160 #endif /* __mips >= 3 && !fpu(single) */
1161
1162                 default:
1163                         if (MIPSInst_FUNC(ir) >= fcmp_op) {
1164                                 unsigned cmpop = MIPSInst_FUNC(ir) - fcmp_op;
1165                                 ieee754dp fs, ft;
1166
1167                                 DPFROMREG(fs, MIPSInst_FS(ir));
1168                                 DPFROMREG(ft, MIPSInst_FT(ir));
1169                                 rv.w = ieee754dp_cmp(fs, ft,
1170                                         cmptab[cmpop & 0x7], cmpop & 0x8);
1171                                 rfmt = -1;
1172                                 if ((cmpop & 0x8)
1173                                         &&
1174                                         ieee754_cxtest
1175                                         (IEEE754_INVALID_OPERATION))
1176                                         rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
1177                                 else
1178                                         goto copcsr;
1179
1180                         }
1181                         else {
1182                                 return SIGILL;
1183                         }
1184                         break;
1185                 }
1186                 break;
1187         }
1188 #endif /* ifndef SINGLE_ONLY_FPU */
1189
1190         case w_fmt:{
1191                 ieee754sp fs;
1192
1193                 switch (MIPSInst_FUNC(ir)) {
1194                 case fcvts_op:
1195                         /* convert word to single precision real */
1196                         SPFROMREG(fs, MIPSInst_FS(ir));
1197                         rv.s = ieee754sp_fint(fs.bits);
1198                         rfmt = s_fmt;
1199                         goto copcsr;
1200 #ifndef SINGLE_ONLY_FPU
1201                 case fcvtd_op:
1202                         /* convert word to double precision real */
1203                         SPFROMREG(fs, MIPSInst_FS(ir));
1204                         rv.d = ieee754dp_fint(fs.bits);
1205                         rfmt = d_fmt;
1206                         goto copcsr;
1207 #endif
1208                 default:
1209                         return SIGILL;
1210                 }
1211                 break;
1212         }
1213
1214 #if defined(__mips64) && !defined(SINGLE_ONLY_FPU)
1215         case l_fmt:{
1216                 switch (MIPSInst_FUNC(ir)) {
1217                 case fcvts_op:
1218                         /* convert long to single precision real */
1219                         rv.s = ieee754sp_flong(ctx->fpr[MIPSInst_FS(ir)]);
1220                         rfmt = s_fmt;
1221                         goto copcsr;
1222                 case fcvtd_op:
1223                         /* convert long to double precision real */
1224                         rv.d = ieee754dp_flong(ctx->fpr[MIPSInst_FS(ir)]);
1225                         rfmt = d_fmt;
1226                         goto copcsr;
1227                 default:
1228                         return SIGILL;
1229                 }
1230                 break;
1231         }
1232 #endif
1233
1234         default:
1235                 return SIGILL;
1236         }
1237
1238         /*
1239          * Update the fpu CSR register for this operation.
1240          * If an exception is required, generate a tidy SIGFPE exception,
1241          * without updating the result register.
1242          * Note: cause exception bits do not accumulate, they are rewritten
1243          * for each op; only the flag/sticky bits accumulate.
1244          */
1245         ctx->fcr31 = (ctx->fcr31 & ~FPU_CSR_ALL_X) | rcsr;
1246         if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
1247                 /*printk ("SIGFPE: fpu csr = %08x\n",ctx->fcr31); */
1248                 return SIGFPE;
1249         }
1250
1251         /*
1252          * Now we can safely write the result back to the register file.
1253          */
1254         switch (rfmt) {
1255         case -1:{
1256 #if __mips >= 4
1257                 cond = fpucondbit[MIPSInst_FD(ir) >> 2];
1258 #else
1259                 cond = FPU_CSR_COND;
1260 #endif
1261                 if (rv.w)
1262                         ctx->fcr31 |= cond;
1263                 else
1264                         ctx->fcr31 &= ~cond;
1265                 break;
1266         }
1267 #ifndef SINGLE_ONLY_FPU
1268         case d_fmt:
1269                 DPTOREG(rv.d, MIPSInst_FD(ir));
1270                 break;
1271 #endif
1272         case s_fmt:
1273                 SPTOREG(rv.s, MIPSInst_FD(ir));
1274                 break;
1275         case w_fmt:
1276                 SITOREG(rv.w, MIPSInst_FD(ir));
1277                 break;
1278 #if defined(__mips64) && !defined(SINGLE_ONLY_FPU)
1279         case l_fmt:
1280                 DITOREG(rv.l, MIPSInst_FD(ir));
1281                 break;
1282 #endif
1283         default:
1284                 return SIGILL;
1285         }
1286
1287         return 0;
1288 }
1289
1290 int fpu_emulator_cop1Handler(struct pt_regs *xcp,
1291         struct mips_fpu_soft_struct *ctx)
1292 {
1293         unsigned long oldepc, prevepc;
1294         mips_instruction insn;
1295         int sig = 0;
1296
1297         oldepc = xcp->cp0_epc;
1298         do {
1299                 prevepc = xcp->cp0_epc;
1300
1301                 if (get_user(insn, (mips_instruction *) xcp->cp0_epc)) {
1302                         fpuemustats.errors++;
1303                         return SIGBUS;
1304                 }
1305                 if (insn == 0)
1306                         xcp->cp0_epc += 4;      /* skip nops */
1307                 else {
1308                         /*
1309                          * The 'ieee754_csr' is an alias of
1310                          * ctx->fcr31.  No need to copy ctx->fcr31 to
1311                          * ieee754_csr.  But ieee754_csr.rm is ieee
1312                          * library modes. (not mips rounding mode)
1313                          */
1314                         /* convert to ieee library modes */
1315                         ieee754_csr.rm = ieee_rm[ieee754_csr.rm];
1316                         sig = cop1Emulate(xcp, ctx);
1317                         /* revert to mips rounding mode */
1318                         ieee754_csr.rm = mips_rm[ieee754_csr.rm];
1319                 }
1320
1321                 if (cpu_has_fpu)
1322                         break;
1323                 if (sig)
1324                         break;
1325
1326                 cond_resched();
1327         } while (xcp->cp0_epc > prevepc);
1328
1329         /* SIGILL indicates a non-fpu instruction */
1330         if (sig == SIGILL && xcp->cp0_epc != oldepc)
1331                 /* but if epc has advanced, then ignore it */
1332                 sig = 0;
1333
1334         return sig;
1335 }