summaryrefslogtreecommitdiff
path: root/arch/mips/isa_traits.hh
blob: 22ae76a442a71c373ecd0b5f14d2a492d7851b9e (plain)
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
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
/*
 * Copyright (c) 2003-2005 The Regents of The University of Michigan
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef __ARCH_MIPS_ISA_TRAITS_HH__
#define __ARCH_MIPS_ISA_TRAITS_HH__

//#include "arch/mips/misc_regfile.hh"
#include "base/misc.hh"
#include "config/full_system.hh"
#include "sim/host.hh"
#include "sim/faults.hh"

#include <vector>

class FastCPU;
class FullCPU;
class Checkpoint;
class ExecContext;

namespace LittleEndianGuest {};

#define TARGET_MIPS

class StaticInst;
class StaticInstPtr;

namespace MIPS34K {
int DTB_ASN_ASN(uint64_t reg);
int ITB_ASN_ASN(uint64_t reg);
};

#if !FULL_SYSTEM
class SyscallReturn {
        public:
           template <class T>
           SyscallReturn(T v, bool s)
           {
               retval = (uint32_t)v;
               success = s;
           }

           template <class T>
           SyscallReturn(T v)
           {
               success = (v >= 0);
               retval = (uint32_t)v;
           }

           ~SyscallReturn() {}

           SyscallReturn& operator=(const SyscallReturn& s) {
               retval = s.retval;
               success = s.success;
               return *this;
           }

           bool successful() { return success; }
           uint64_t value() { return retval; }


       private:
           uint64_t retval;
           bool success;
};
#endif

namespace MipsISA
{
    using namespace LittleEndianGuest;

    typedef uint32_t MachInst;
    typedef uint32_t MachInst;
    typedef uint64_t ExtMachInst;
    typedef uint8_t  RegIndex;
//  typedef uint64_t Addr;

       // Constants Related to the number of registers

    const int NumIntArchRegs = 32;
    const int NumPALShadowRegs = 8;
    const int NumFloatArchRegs = 32;
    // @todo: Figure out what this number really should be.
    const int NumMiscArchRegs = 32;

    const int NumIntRegs = NumIntArchRegs + NumPALShadowRegs;
    const int NumFloatRegs = NumFloatArchRegs;
    const int NumMiscRegs = NumMiscArchRegs;

    const int TotalNumRegs = NumIntRegs + NumFloatRegs +
    NumMiscRegs + 0/*NumInternalProcRegs*/;

    const int TotalDataRegs = NumIntRegs + NumFloatRegs;

    // Static instruction parameters
    const int MaxInstSrcRegs = 3;
    const int MaxInstDestRegs = 2;

    // semantically meaningful register indices
    const int ZeroReg = 0;
    const int AssemblerReg = 1;
    const int ReturnValueReg1 = 2;
    const int ReturnValueReg2 = 3;
    const int ArgumentReg0 = 4;
    const int ArgumentReg1 = 5;
    const int ArgumentReg2 = 6;
    const int ArgumentReg3 = 7;
    const int KernelReg0 = 26;
    const int KernelReg1 = 27;
    const int GlobalPointerReg = 28;
    const int StackPointerReg = 29;
    const int FramePointerReg = 30;
    const int ReturnAddressReg = 31;

    const int SyscallNumReg = ReturnValueReg1;
    const int SyscallPseudoReturnReg = ReturnValueReg1;
    const int SyscallSuccessReg = ArgumentReg3;

    const int LogVMPageSize = 13;	// 8K bytes
    const int VMPageSize = (1 << LogVMPageSize);

    const int BranchPredAddrShiftAmt = 2; // instructions are 4-byte aligned

    const int MachineBytes = 4;
    const int WordBytes = 4;
    const int HalfwordBytes = 2;
    const int ByteBytes = 1;


    // These enumerate all the registers for dependence tracking.
    enum DependenceTags {
        // 0..31 are the integer regs 0..31
        // 32..63 are the FP regs 0..31, i.e. use (reg + FP_Base_DepTag)
        FP_Base_DepTag = 32,
        Ctrl_Base_DepTag = 64,
        Fpcr_DepTag = 64,		// floating point control register
        Uniq_DepTag = 65,
        IPR_Base_DepTag = 66,
        MiscReg_DepTag = 67
    };

    typedef uint64_t IntReg;

    class IntRegFile
    {
      protected:
        IntReg regs[NumIntRegs];

      public:
        IntReg readReg(int intReg)
        {
            return regs[intReg];
        }

        Fault setReg(int intReg, const IntReg &val)
        {
            regs[intReg] = val;
            return NoFault;
        }

        void serialize(std::ostream &os);

        void unserialize(Checkpoint *cp, const std::string &section);

    };

/* floating point register file entry type
    typedef union {
        uint64_t q;
        double d;
    } FloatReg;*/

    typedef double FloatReg;
    typedef uint64_t FloatRegBits;

/*typedef union {
        uint64_t q[NumFloatRegs];	// integer qword view
        double d[NumFloatRegs];		// double-precision floating point view
    } FloatRegFile;*/

   class FloatRegFile
    {
      protected:

        FloatRegBits q[NumFloatRegs];	// integer qword view
        double d[NumFloatRegs];	// double-precision floating point view

      public:

        FloatReg readReg(int floatReg)
        {
            return d[floatReg];
        }

        FloatReg readReg(int floatReg, int width)
        {
            return readReg(floatReg);
        }

        FloatRegBits readRegBits(int floatReg)
        {
            return q[floatReg];
        }

        FloatRegBits readRegBits(int floatReg, int width)
        {
            return readRegBits(floatReg);
        }

        Fault setReg(int floatReg, const FloatReg &val)
        {
            d[floatReg] = val;
            return NoFault;
        }

        Fault setReg(int floatReg, const FloatReg &val, int width)
        {
            return setReg(floatReg, val);
        }

        Fault setRegBits(int floatReg, const FloatRegBits &val)
        {
            q[floatReg] = val;
            return NoFault;
        }

        Fault setRegBits(int floatReg, const FloatRegBits &val, int width)
        {
            return setRegBits(floatReg, val);
        }

        void serialize(std::ostream &os);

        void unserialize(Checkpoint *cp, const std::string &section);

    };

        void copyRegs(ExecContext *src, ExecContext *dest);

    // cop-0/cop-1 system control register file
    typedef uint64_t MiscReg;
//typedef MiscReg MiscRegFile[NumMiscRegs];
    class MiscRegFile {

      protected:
        uint64_t	fpcr;		// floating point condition codes
        uint64_t	uniq;		// process-unique register
        bool		lock_flag;	// lock flag for LL/SC
        Addr		lock_addr;	// lock address for LL/SC

        MiscReg miscRegFile[NumMiscRegs];

      public:
        //These functions should be removed once the simplescalar cpu model
        //has been replaced.
        int getInstAsid();
        int getDataAsid();

        void copyMiscRegs(ExecContext *xc);

        MiscReg readReg(int misc_reg)
        { return miscRegFile[misc_reg]; }

        MiscReg readRegWithEffect(int misc_reg, Fault &fault, ExecContext *xc)
        { return miscRegFile[misc_reg];}

        Fault setReg(int misc_reg, const MiscReg &val)
        { miscRegFile[misc_reg] = val; return NoFault; }

        Fault setRegWithEffect(int misc_reg, const MiscReg &val,
                               ExecContext *xc)
        { miscRegFile[misc_reg] = val; return NoFault; }

#if FULL_SYSTEM
        void clearIprs() { }

      protected:
        InternalProcReg ipr[NumInternalProcRegs]; // Internal processor regs

      private:
        MiscReg readIpr(int idx, Fault &fault, ExecContext *xc) { }

        Fault setIpr(int idx, uint64_t val, ExecContext *xc) { }
#endif
        friend class RegFile;
    };

    enum MiscRegTags {
        //Coprocessor 0 Registers
        //Reference MIPS32 Arch. for Programmers, Vol. III, Ch.8
        //(Register Number-Register Select) Summary of Register
        //------------------------------------------------------
        Index = 0,       //0-0 Index into the TLB array

        MVPControl = 1,  //0-1 Per-processor register containing global
                     //MIPS® MT configuration data

        MVPConf0 = 2,    //0-2 Per-processor register containing global
                     //MIPS® MT configuration data

        MVPConf1 = 3,    //0-3 Per-processor register containing global
                     //MIPS® MT configuration data

        Random = 8,      //1-0 Randomly generated index into the TLB array

        VPEControl = 9,  //1-1 Per-VPE register containing relatively volatile
                     //thread configuration data

        VPEConf0 = 10,    //1-2 Per-VPE multi-thread configuration
                     //information


        VPEConf1 = 11,    //1-2 Per-VPE multi-thread configuration
                     //information

        YQMask = 12,      //Per-VPE register defining which YIELD
                     //qualifier bits may be used without generating
                     //an exception

        VPESchedule = 13,
        VPEScheFBack =  14,
        VPEOpt = 15,
        EntryLo0 = 16, // Bank 3: 16 - 23
        TCStatus = 17,
        TCBind = 18,
        TCRestart = 19,
        TCHalt = 20,
        TCContext = 21,
        TCSchedule = 22,
        TCScheFBack = 23,

        EntryLo1 = 24,// Bank 4: 24 - 31

        Context = 32, // Bank 5: 32 - 39
        ContextConfig = 33,

        //PageMask = 40, //Bank 6: 40 - 47
        PageGrain = 41,

        Wired = 48, //Bank 7:48 - 55
        SRSConf0 = 49,
        SRSConf1 = 50,
        SRSConf2 = 51,
        SRSConf3 = 52,
        SRSConf4 = 53,
        BadVAddr = 54,

        HWRena = 56,//Bank 8:56 - 63

        Count = 64, //Bank 9:64 - 71

        EntryHi = 72,//Bank 10:72 - 79

        Compare = 80,//Bank 11:80 - 87

        Status = 88,//Bank 12:88 - 96     //12-0 Processor status and control
        IntCtl = 89,                      //12-1 Interrupt system status and control
        SRSCtl = 90,                      //12-2 Shadow register set status and control
        SRSMap = 91,                      //12-3 Shadow set IPL mapping

        Cause = 97,//97-104      //13-0 Cause of last general exception

        EPC = 105,//105-112        //14-0 Program counter at last exception

        PRId = 113,//113-120,       //15-0 Processor identification and revision
        EBase = 114,      //15-1 Exception vector base register

        Config = 121,//Bank 16: 121-128
        Config1 = 122,
        Config2 = 123,
        Config3 = 124,
        Config6 = 127,
        Config7 = 128,


        LLAddr = 129,//Bank 17: 129-136

        WatchLo0 = 137,//Bank 18: 137-144
        WatchLo1 = 138,
        WatchLo2 = 139,
        WatchLo3 = 140,
        WatchLo4 = 141,
        WatchLo5 = 142,
        WatchLo6 = 143,
        WatchLo7 = 144,

        WatchHi0 = 145,//Bank 19: 145-152
        WatchHi1 = 146,
        WatchHi2 = 147,
        WatchHi3 = 148,
        WatchHi4 = 149,
        WatchHi5 = 150,
        WatchHi6 = 151,
        WatchHi7 = 152,

        XCContext64 = 153,//Bank 20: 153-160

        //Bank 21: 161-168

        //Bank 22: 169-176

        Debug = 177, //Bank 23: 177-184
        TraceControl1 = 178,
        TraceControl2 = 179,
        UserTraceData = 180,
        TraceBPC = 181,

        DEPC = 185,//Bank 24: 185-192

        PerfCnt0 = 193,//Bank 25: 193 - 200
        PerfCnt1 = 194,
        PerfCnt2 = 195,
        PerfCnt3 = 196,
        PerfCnt4 = 197,
        PerfCnt5 = 198,
        PerfCnt6 = 199,
        PerfCnt7 = 200,

        ErrCtl = 201, //Bank 26: 201 - 208

        CacheErr0 = 209, //Bank 27: 209 - 216
        CacheErr1 = 210,
        CacheErr2 = 211,
        CacheErr3 = 212,

        TagLo0 = 217,//Bank 28: 217 - 224
        DataLo1 = 218,
        TagLo2 = 219,
        DataLo3 = 220,
        TagLo4 = 221,
        DataLo5 = 222,
        TagLo6 = 223,
        DataLo7 = 234,

        TagHi0 = 233,//Bank 29: 233 - 240
        DataHi1 = 234,
        TagHi2 = 235,
        DataHi3 = 236,
        TagHi4 = 237,
        DataHi5 = 238,
        TagHi6 = 239,
        DataHi7 = 240,


        ErrorEPC = 249,//Bank 30: 241 - 248

        DESAVE = 257,//Bank 31: 249-256

        //More Misc. Regs
        Hi,
        Lo,
        FIR,
        FCSR,
        FPCR,

        //Alpha Regs, but here now, for
        //compiling sake
        UNIQ,
        LockAddr,
        LockFlag
    };

extern const Addr PageShift;
extern const Addr PageBytes;
extern const Addr PageMask;
extern const Addr PageOffset;

#if FULL_SYSTEM

    typedef uint64_t InternalProcReg;

#include "arch/mips/isa_fullsys_traits.hh"

#else
    enum {
        NumInternalProcRegs = 0
    };
#endif

    typedef union {
        IntReg  intreg;
        FloatReg   fpreg;
        MiscReg ctrlreg;
    } AnyReg;

    class RegFile {
      protected:
        IntRegFile intRegFile;		// (signed) integer register file
        FloatRegFile floatRegFile;	// floating point register file
        MiscRegFile miscRegFile;	// control register file

      public:

        void clear()
        {
            bzero(&intRegFile, sizeof(intRegFile));
            bzero(&floatRegFile, sizeof(floatRegFile));
            bzero(&miscRegFile, sizeof(miscRegFile));
        }

        MiscReg readMiscReg(int miscReg)
        {
            return miscRegFile.readReg(miscReg);
        }

        MiscReg readMiscRegWithEffect(int miscReg,
                Fault &fault, ExecContext *xc)
        {
            fault = NoFault;
            return miscRegFile.readRegWithEffect(miscReg, fault, xc);
        }

        Fault setMiscReg(int miscReg, const MiscReg &val)
        {
            return miscRegFile.setReg(miscReg, val);
        }

        Fault setMiscRegWithEffect(int miscReg, const MiscReg &val,
                ExecContext * xc)
        {
            return miscRegFile.setRegWithEffect(miscReg, val, xc);
        }

        FloatReg readFloatReg(int floatReg)
        {
            return floatRegFile.readReg(floatReg);
        }

        FloatReg readFloatReg(int floatReg, int width)
        {
            return readFloatReg(floatReg);
        }

        FloatRegBits readFloatRegBits(int floatReg)
        {
            return floatRegFile.readRegBits(floatReg);
        }

        FloatRegBits readFloatRegBits(int floatReg, int width)
        {
            return readFloatRegBits(floatReg);
        }

        Fault setFloatReg(int floatReg, const FloatReg &val)
        {
            return floatRegFile.setReg(floatReg, val);
        }

        Fault setFloatReg(int floatReg, const FloatReg &val, int width)
        {
            return setFloatReg(floatReg, val);
        }

        Fault setFloatRegBits(int floatReg, const FloatRegBits &val)
        {
            return floatRegFile.setRegBits(floatReg, val);
        }

        Fault setFloatRegBits(int floatReg, const FloatRegBits &val, int width)
        {
            return setFloatRegBits(floatReg, val);
        }

        IntReg readIntReg(int intReg)
        {
            return intRegFile.readReg(intReg);
        }

        Fault setIntReg(int intReg, const IntReg &val)
        {
            return intRegFile.setReg(intReg, val);
        }
      protected:

        Addr pc;			// program counter
        Addr npc;			// next-cycle program counter
        Addr nnpc;			// next-next-cycle program counter
                                        // used to implement branch delay slot
                                        // not real register
      public:
        Addr readPC()
        {
            return pc;
        }

        void setPC(Addr val)
        {
            pc = val;
        }

        Addr readNextPC()
        {
            return npc;
        }

        void setNextPC(Addr val)
        {
            npc = val;
        }

        Addr readNextNPC()
        {
            return nnpc;
        }

        void setNextNPC(Addr val)
        {
            nnpc = val;
        }

        MiscReg hi;                     // MIPS HI Register
        MiscReg lo;                     // MIPS LO Register


#if FULL_SYSTEM
        IntReg palregs[NumIntRegs];	// PAL shadow registers
        InternalProcReg ipr[NumInternalProcRegs]; // internal processor regs
        int intrflag;			// interrupt flag
        bool pal_shadow;		// using pal_shadow registers
        inline int instAsid() { return MIPS34K::ITB_ASN_ASN(ipr[IPR_ITB_ASN]); }
        inline int dataAsid() { return MIPS34K::DTB_ASN_ASN(ipr[IPR_DTB_ASN]); }
#endif // FULL_SYSTEM

        //void initCP0Regs();
        void serialize(std::ostream &os);
        void unserialize(Checkpoint *cp, const std::string &section);

        void createCP0Regs();
        void coldReset();

        typedef int ContextParam;
        typedef int ContextVal;

        void changeContext(ContextParam param, ContextVal val)
        {
        }
    };

    StaticInstPtr decodeInst(ExtMachInst);

    // return a no-op instruction... used for instruction fetch faults
    extern const MachInst NoopMachInst;

    enum annotes {
        ANNOTE_NONE = 0,
        // An impossible number for instruction annotations
        ITOUCH_ANNOTE = 0xffffffff,
    };

//void getMiscRegIdx(int reg_name,int &idx, int &sel);

    static inline ExtMachInst
    makeExtMI(MachInst inst, const uint64_t &pc) {
#if FULL_SYSTEM
        ExtMachInst ext_inst = inst;
        if (pc && 0x1)
            return ext_inst|=(static_cast<ExtMachInst>(pc & 0x1) << 32);
        else
            return ext_inst;
#else
        return ExtMachInst(inst);
#endif
    }

    static inline bool isCallerSaveIntegerRegister(unsigned int reg) {
        panic("register classification not implemented");
        return (reg >= 1 && reg <= 8 || reg >= 22 && reg <= 25 || reg == 27);
    }

    static inline bool isCalleeSaveIntegerRegister(unsigned int reg) {
        panic("register classification not implemented");
        return (reg >= 9 && reg <= 15);
    }

    static inline bool isCallerSaveFloatRegister(unsigned int reg) {
        panic("register classification not implemented");
        return false;
    }

    static inline bool isCalleeSaveFloatRegister(unsigned int reg) {
        panic("register classification not implemented");
        return false;
    }

    static inline Addr alignAddress(const Addr &addr,
                                         unsigned int nbytes) {
        return (addr & ~(nbytes - 1));
    }

    // Instruction address compression hooks
    static inline Addr realPCToFetchPC(const Addr &addr) {
        return addr;
    }

    static inline Addr fetchPCToRealPC(const Addr &addr) {
        return addr;
    }

    // the size of "fetched" instructions (not necessarily the size
    // of real instructions for PISA)
    static inline size_t fetchInstSize() {
        return sizeof(MachInst);
    }

    static inline MachInst makeRegisterCopy(int dest, int src) {
        panic("makeRegisterCopy not implemented");
        return 0;
    }

    static inline void setSyscallReturn(SyscallReturn return_value, RegFile *regs)
    {
        if (return_value.successful()) {
            // no error
            regs->setIntReg(SyscallSuccessReg, 0);
            regs->setIntReg(ReturnValueReg1, return_value.value());
        } else {
            // got an error, return details
            regs->setIntReg(SyscallSuccessReg, (IntReg) -1);
            regs->setIntReg(ReturnValueReg1, -return_value.value());
        }
    }

    // Machine operations

    void saveMachineReg(AnyReg &savereg, const RegFile &reg_file,
                               int regnum);

    void restoreMachineReg(RegFile &regs, const AnyReg &reg,
                                  int regnum);

#if 0
    static void serializeSpecialRegs(const Serializable::Proxy &proxy,
                                     const RegFile &regs);

    static void unserializeSpecialRegs(const IniFile *db,
                                       const std::string &category,
                                       ConfigNode *node,
                                       RegFile &regs);
#endif

    /**
     * Function to insure ISA semantics about 0 registers.
     * @param xc The execution context.
     */
    template <class XC>
    void zeroRegisters(XC *xc);

    const Addr MaxAddr = (Addr)-1;
};

#if FULL_SYSTEM
//typedef TheISA::InternalProcReg InternalProcReg;
//const int NumInternalProcRegs  = TheISA::NumInternalProcRegs;
//const int NumInterruptLevels = TheISA::NumInterruptLevels;

#include "arch/mips/mips34k.hh"
#endif

using namespace MipsISA;

#endif // __ARCH_MIPS_ISA_TRAITS_HH__