isa.cc revision 8232:b28d06a175be 
1/*
2 * Copyright (c) 2009 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Gabe Black
29 */
30
31#include "arch/mips/isa.hh"
32#include "arch/mips/mt.hh"
33#include "arch/mips/mt_constants.hh"
34#include "arch/mips/pra_constants.hh"
35#include "base/bitfield.hh"
36#include "cpu/base.hh"
37#include "cpu/thread_context.hh"
38#include "debug/MipsPRA.hh"
39
40namespace MipsISA
41{
42
43std::string
44ISA::miscRegNames[NumMiscRegs] =
45{
46    "Index", "MVPControl", "MVPConf0", "MVPConf1", "", "", "", "",
47    "Random", "VPEControl", "VPEConf0", "VPEConf1",
48        "YQMask", "VPESchedule", "VPEScheFBack", "VPEOpt",
49    "EntryLo0", "TCStatus", "TCBind", "TCRestart",
50        "TCHalt", "TCContext", "TCSchedule", "TCScheFBack",
51    "EntryLo1", "", "", "", "", "", "", "",
52    "Context", "ContextConfig", "", "", "", "", "", "",
53    "PageMask", "PageGrain", "", "", "", "", "", "",
54    "Wired", "SRSConf0", "SRCConf1", "SRSConf2",
55        "SRSConf3", "SRSConf4", "", "",
56    "HWREna", "", "", "", "", "", "", "",
57    "BadVAddr", "", "", "", "", "", "", "",
58    "Count", "", "", "", "", "", "", "",
59    "EntryHi", "", "", "", "", "", "", "",
60    "Compare", "", "", "", "", "", "", "",
61    "Status", "IntCtl", "SRSCtl", "SRSMap", "", "", "", "",
62    "Cause", "", "", "", "", "", "", "",
63    "EPC", "", "", "", "", "", "", "",
64    "PRId", "EBase", "", "", "", "", "", "",
65    "Config", "Config1", "Config2", "Config3", "", "", "", "",
66    "LLAddr", "", "", "", "", "", "", "",
67    "WatchLo0", "WatchLo1", "WatchLo2", "WatchLo3",
68        "WatchLo4", "WatchLo5", "WatchLo6", "WatchLo7",
69    "WatchHi0", "WatchHi1", "WatchHi2", "WatchHi3",
70        "WatchHi4", "WatchHi5", "WatchHi6", "WatchHi7",
71    "XCContext64", "", "", "", "", "", "", "",
72    "", "", "", "", "", "", "", "",
73    "", "", "", "", "", "", "", "",
74    "Debug", "TraceControl1", "TraceControl2", "UserTraceData",
75        "TraceBPC", "", "", "",
76    "DEPC", "", "", "", "", "", "", "",
77    "PerfCnt0", "PerfCnt1", "PerfCnt2", "PerfCnt3",
78        "PerfCnt4", "PerfCnt5", "PerfCnt6", "PerfCnt7",
79    "ErrCtl", "", "", "", "", "", "", "",
80    "CacheErr0", "CacheErr1", "CacheErr2", "CacheErr3", "", "", "", "",
81    "TagLo0", "DataLo1", "TagLo2", "DataLo3",
82        "TagLo4", "DataLo5", "TagLo6", "DataLo7",
83    "TagHi0", "DataHi1", "TagHi2", "DataHi3",
84        "TagHi4", "DataHi5", "TagHi6", "DataHi7",
85    "ErrorEPC", "", "", "", "", "", "", "",
86    "DESAVE", "", "", "", "", "", "", "",
87    "LLFlag"
88};
89
90ISA::ISA(uint8_t num_threads, uint8_t num_vpes)
91{
92    numThreads = num_threads;
93    numVpes = num_vpes;
94
95    miscRegFile.resize(NumMiscRegs);
96    bankType.resize(NumMiscRegs);
97
98    for (int i=0; i < NumMiscRegs; i++) {
99        miscRegFile[i].resize(1);
100        bankType[i] = perProcessor;
101    }
102
103    miscRegFile_WriteMask.resize(NumMiscRegs);
104
105    for (int i = 0; i < NumMiscRegs; i++) {
106        miscRegFile_WriteMask[i].push_back(0);
107    }
108
109    // Initialize all Per-VPE regs
110    uint32_t per_vpe_regs[] = { MISCREG_VPE_CONTROL,
111                                MISCREG_VPE_CONF0, MISCREG_VPE_CONF1,
112                                MISCREG_YQMASK,
113                                MISCREG_VPE_SCHEDULE, MISCREG_VPE_SCHEFBACK,
114                                MISCREG_VPE_OPT, MISCREG_SRS_CONF0,
115                                MISCREG_SRS_CONF1, MISCREG_SRS_CONF2,
116                                MISCREG_SRS_CONF3, MISCREG_SRS_CONF4,
117                                MISCREG_EBASE
118                              };
119    uint32_t num_vpe_regs = sizeof(per_vpe_regs) / 4;
120    for (int i = 0; i < num_vpe_regs; i++) {
121        if (numVpes > 1) {
122            miscRegFile[per_vpe_regs[i]].resize(numVpes);
123        }
124        bankType[per_vpe_regs[i]] = perVirtProcessor;
125    }
126
127    // Initialize all Per-TC regs
128    uint32_t per_tc_regs[] = { MISCREG_STATUS,
129                               MISCREG_TC_STATUS, MISCREG_TC_BIND,
130                               MISCREG_TC_RESTART, MISCREG_TC_HALT,
131                               MISCREG_TC_CONTEXT, MISCREG_TC_SCHEDULE,
132                               MISCREG_TC_SCHEFBACK,
133                               MISCREG_DEBUG, MISCREG_LLADDR
134                             };
135    uint32_t num_tc_regs = sizeof(per_tc_regs) /  4;
136
137    for (int i = 0; i < num_tc_regs; i++) {
138        miscRegFile[per_tc_regs[i]].resize(numThreads);
139        bankType[per_tc_regs[i]] = perThreadContext;
140    }
141
142    clear();
143}
144
145void
146ISA::clear()
147{
148    for(int i = 0; i < NumMiscRegs; i++) {
149        for (int j = 0; j < miscRegFile[i].size(); j++)
150            miscRegFile[i][j] = 0;
151
152        for (int k = 0; k < miscRegFile_WriteMask[i].size(); k++)
153            miscRegFile_WriteMask[i][k] = (long unsigned int)(-1);
154    }
155}
156
157
158void
159ISA::configCP()
160{
161    DPRINTF(MipsPRA, "Resetting CP0 State with %i TCs and %i VPEs\n",
162            numThreads, numVpes);
163
164    CoreSpecific cp;
165    panic("CP state must be set before the following code is used");
166
167    // Do Default CP0 initialization HERE
168
169    // Do Initialization for MT cores here (eventually use
170    // core_name parameter to toggle this initialization)
171    // ===================================================
172    DPRINTF(MipsPRA, "Initializing CP0 State.... ");
173
174    PRIdReg procId = readMiscRegNoEffect(MISCREG_PRID);
175    procId.coOp = cp.CP0_PRId_CompanyOptions;
176    procId.coId = cp.CP0_PRId_CompanyID;
177    procId.procId = cp.CP0_PRId_ProcessorID;
178    procId.rev = cp.CP0_PRId_Revision;
179    setMiscRegNoEffect(MISCREG_PRID, procId);
180
181    // Now, create Write Mask for ProcID register
182    MiscReg procIDMask = 0; // Read-Only register
183    replaceBits(procIDMask, 0, 32, 0);
184    setRegMask(MISCREG_PRID, procIDMask);
185
186    // Config
187    ConfigReg cfg = readMiscRegNoEffect(MISCREG_CONFIG);
188    cfg.be = cp.CP0_Config_BE;
189    cfg.at = cp.CP0_Config_AT;
190    cfg.ar = cp.CP0_Config_AR;
191    cfg.mt = cp.CP0_Config_MT;
192    cfg.vi = cp.CP0_Config_VI;
193    cfg.m = 1;
194    setMiscRegNoEffect(MISCREG_CONFIG, cfg);
195    // Now, create Write Mask for Config register
196    MiscReg cfg_Mask = 0x7FFF0007;
197    replaceBits(cfg_Mask, 0, 32, 0);
198    setRegMask(MISCREG_CONFIG, cfg_Mask);
199
200    // Config1
201    Config1Reg cfg1 = readMiscRegNoEffect(MISCREG_CONFIG1);
202    cfg1.mmuSize = cp.CP0_Config1_MMU;
203    cfg1.is = cp.CP0_Config1_IS;
204    cfg1.il = cp.CP0_Config1_IL;
205    cfg1.ia = cp.CP0_Config1_IA;
206    cfg1.ds = cp.CP0_Config1_DS;
207    cfg1.dl = cp.CP0_Config1_DL;
208    cfg1.da = cp.CP0_Config1_DA;
209    cfg1.fp = cp.CP0_Config1_FP;
210    cfg1.ep = cp.CP0_Config1_EP;
211    cfg1.wr = cp.CP0_Config1_WR;
212    cfg1.md = cp.CP0_Config1_MD;
213    cfg1.c2 = cp.CP0_Config1_C2;
214    cfg1.pc = cp.CP0_Config1_PC;
215    cfg1.m = cp.CP0_Config1_M;
216    setMiscRegNoEffect(MISCREG_CONFIG1, cfg1);
217    // Now, create Write Mask for Config register
218    MiscReg cfg1_Mask = 0; // Read Only Register
219    replaceBits(cfg1_Mask, 0, 32, 0);
220    setRegMask(MISCREG_CONFIG1, cfg1_Mask);
221
222    // Config2
223    Config2Reg cfg2 = readMiscRegNoEffect(MISCREG_CONFIG2);
224    cfg2.tu = cp.CP0_Config2_TU;
225    cfg2.ts = cp.CP0_Config2_TS;
226    cfg2.tl = cp.CP0_Config2_TL;
227    cfg2.ta = cp.CP0_Config2_TA;
228    cfg2.su = cp.CP0_Config2_SU;
229    cfg2.ss = cp.CP0_Config2_SS;
230    cfg2.sl = cp.CP0_Config2_SL;
231    cfg2.sa = cp.CP0_Config2_SA;
232    cfg2.m = cp.CP0_Config2_M;
233    setMiscRegNoEffect(MISCREG_CONFIG2, cfg2);
234    // Now, create Write Mask for Config register
235    MiscReg cfg2_Mask = 0x7000F000; // Read Only Register
236    replaceBits(cfg2_Mask, 0, 32, 0);
237    setRegMask(MISCREG_CONFIG2, cfg2_Mask);
238
239    // Config3
240    Config3Reg cfg3 = readMiscRegNoEffect(MISCREG_CONFIG3);
241    cfg3.dspp = cp.CP0_Config3_DSPP;
242    cfg3.lpa = cp.CP0_Config3_LPA;
243    cfg3.veic = cp.CP0_Config3_VEIC;
244    cfg3.vint = cp.CP0_Config3_VInt;
245    cfg3.sp = cp.CP0_Config3_SP;
246    cfg3.mt = cp.CP0_Config3_MT;
247    cfg3.sm = cp.CP0_Config3_SM;
248    cfg3.tl = cp.CP0_Config3_TL;
249    setMiscRegNoEffect(MISCREG_CONFIG3, cfg3);
250    // Now, create Write Mask for Config register
251    MiscReg cfg3_Mask = 0; // Read Only Register
252    replaceBits(cfg3_Mask, 0, 32, 0);
253    setRegMask(MISCREG_CONFIG3, cfg3_Mask);
254
255    // EBase - CPUNum
256    EBaseReg eBase = readMiscRegNoEffect(MISCREG_EBASE);
257    eBase.cpuNum = cp.CP0_EBase_CPUNum;
258    replaceBits(eBase, 31, 31, 1);
259    setMiscRegNoEffect(MISCREG_EBASE, eBase);
260    // Now, create Write Mask for Config register
261    MiscReg EB_Mask = 0x3FFFF000;// Except Exception Base, the
262                                 // entire register is read only
263    replaceBits(EB_Mask, 0, 32, 0);
264    setRegMask(MISCREG_EBASE, EB_Mask);
265
266    // SRS Control - HSS (Highest Shadow Set)
267    SRSCtlReg scsCtl = readMiscRegNoEffect(MISCREG_SRSCTL);
268    scsCtl.hss = cp.CP0_SrsCtl_HSS;
269    setMiscRegNoEffect(MISCREG_SRSCTL, scsCtl);
270    // Now, create Write Mask for the SRS Ctl register
271    MiscReg SC_Mask = 0x0000F3C0;
272    replaceBits(SC_Mask, 0, 32, 0);
273    setRegMask(MISCREG_SRSCTL, SC_Mask);
274
275    // IntCtl - IPTI, IPPCI
276    IntCtlReg intCtl = readMiscRegNoEffect(MISCREG_INTCTL);
277    intCtl.ipti = cp.CP0_IntCtl_IPTI;
278    intCtl.ippci = cp.CP0_IntCtl_IPPCI;
279    setMiscRegNoEffect(MISCREG_INTCTL, intCtl);
280    // Now, create Write Mask for the IntCtl register
281    MiscReg IC_Mask = 0x000003E0;
282    replaceBits(IC_Mask, 0, 32, 0);
283    setRegMask(MISCREG_INTCTL, IC_Mask);
284
285    // Watch Hi - M - FIXME (More than 1 Watch register)
286    WatchHiReg watchHi = readMiscRegNoEffect(MISCREG_WATCHHI0);
287    watchHi.m = cp.CP0_WatchHi_M;
288    setMiscRegNoEffect(MISCREG_WATCHHI0, watchHi);
289    // Now, create Write Mask for the IntCtl register
290    MiscReg wh_Mask = 0x7FFF0FFF;
291    replaceBits(wh_Mask, 0, 32, 0);
292    setRegMask(MISCREG_WATCHHI0, wh_Mask);
293
294    // Perf Ctr - M - FIXME (More than 1 PerfCnt Pair)
295    PerfCntCtlReg perfCntCtl = readMiscRegNoEffect(MISCREG_PERFCNT0);
296    perfCntCtl.m = cp.CP0_PerfCtr_M;
297    perfCntCtl.w = cp.CP0_PerfCtr_W;
298    setMiscRegNoEffect(MISCREG_PERFCNT0, perfCntCtl);
299    // Now, create Write Mask for the IntCtl register
300    MiscReg pc_Mask = 0x00007FF;
301    replaceBits(pc_Mask, 0, 32, 0);
302    setRegMask(MISCREG_PERFCNT0, pc_Mask);
303
304    // Random
305    setMiscRegNoEffect(MISCREG_CP0_RANDOM, 63);
306    // Now, create Write Mask for the IntCtl register
307    MiscReg random_Mask = 0;
308    replaceBits(random_Mask, 0, 32, 0);
309    setRegMask(MISCREG_CP0_RANDOM, random_Mask);
310
311    // PageGrain
312    PageGrainReg pageGrain = readMiscRegNoEffect(MISCREG_PAGEGRAIN);
313    pageGrain.esp = cp.CP0_Config3_SP;
314    setMiscRegNoEffect(MISCREG_PAGEGRAIN, pageGrain);
315    // Now, create Write Mask for the IntCtl register
316    MiscReg pg_Mask = 0x10000000;
317    replaceBits(pg_Mask, 0, 32, 0);
318    setRegMask(MISCREG_PAGEGRAIN, pg_Mask);
319
320    // Status
321    StatusReg status = readMiscRegNoEffect(MISCREG_STATUS);
322    // Only CU0 and IE are modified on a reset - everything else needs
323    // to be controlled on a per CPU model basis
324
325    // Enable CP0 on reset
326    // status.cu0 = 1;
327
328    // Enable ERL bit on a reset
329    status.erl = 1;
330    // Enable BEV bit on a reset
331    status.bev = 1;
332
333    setMiscRegNoEffect(MISCREG_STATUS, status);
334    // Now, create Write Mask for the Status register
335    MiscReg stat_Mask = 0xFF78FF17;
336    replaceBits(stat_Mask, 0, 32, 0);
337    setRegMask(MISCREG_STATUS, stat_Mask);
338
339
340    // MVPConf0
341    MVPConf0Reg mvpConf0 = readMiscRegNoEffect(MISCREG_MVP_CONF0);
342    mvpConf0.tca = 1;
343    mvpConf0.pvpe = numVpes - 1;
344    mvpConf0.ptc = numThreads - 1;
345    setMiscRegNoEffect(MISCREG_MVP_CONF0, mvpConf0);
346
347    // VPEConf0
348    VPEConf0Reg vpeConf0 = readMiscRegNoEffect(MISCREG_VPE_CONF0);
349    vpeConf0.mvp = 1;
350    setMiscRegNoEffect(MISCREG_VPE_CONF0, vpeConf0);
351
352    // TCBind
353    for (ThreadID tid = 0; tid < numThreads; tid++) {
354        TCBindReg tcBind = readMiscRegNoEffect(MISCREG_TC_BIND, tid);
355        tcBind.curTC = tid;
356        setMiscRegNoEffect(MISCREG_TC_BIND, tcBind, tid);
357    }
358    // TCHalt
359    TCHaltReg tcHalt = readMiscRegNoEffect(MISCREG_TC_HALT);
360    tcHalt.h = 0;
361    setMiscRegNoEffect(MISCREG_TC_HALT, tcHalt);
362
363    // TCStatus
364    // Set TCStatus Activated to 1 for the initial thread that is running
365    TCStatusReg tcStatus = readMiscRegNoEffect(MISCREG_TC_STATUS);
366    tcStatus.a = 1;
367    setMiscRegNoEffect(MISCREG_TC_STATUS, tcStatus);
368
369    // Set Dynamically Allocatable bit to 1 for all other threads
370    for (ThreadID tid = 1; tid < numThreads; tid++) {
371        tcStatus = readMiscRegNoEffect(MISCREG_TC_STATUS, tid);
372        tcStatus.da = 1;
373        setMiscRegNoEffect(MISCREG_TC_STATUS, tcStatus, tid);
374    }
375
376
377    MiscReg mask = 0x7FFFFFFF;
378
379    // Now, create Write Mask for the Index register
380    replaceBits(mask, 0, 32, 0);
381    setRegMask(MISCREG_INDEX, mask);
382
383    mask = 0x3FFFFFFF;
384    replaceBits(mask, 0, 32, 0);
385    setRegMask(MISCREG_ENTRYLO0, mask);
386    setRegMask(MISCREG_ENTRYLO1, mask);
387
388    mask = 0xFF800000;
389    replaceBits(mask, 0, 32, 0);
390    setRegMask(MISCREG_CONTEXT, mask);
391
392    mask = 0x1FFFF800;
393    replaceBits(mask, 0, 32, 0);
394    setRegMask(MISCREG_PAGEMASK, mask);
395
396    mask = 0x0;
397    replaceBits(mask, 0, 32, 0);
398    setRegMask(MISCREG_BADVADDR, mask);
399    setRegMask(MISCREG_LLADDR, mask);
400
401    mask = 0x08C00300;
402    replaceBits(mask, 0, 32, 0);
403    setRegMask(MISCREG_CAUSE, mask);
404
405}
406
407inline unsigned
408ISA::getVPENum(ThreadID tid)
409{
410    TCBindReg tcBind = miscRegFile[MISCREG_TC_BIND][tid];
411    return tcBind.curVPE;
412}
413
414MiscReg
415ISA::readMiscRegNoEffect(int misc_reg, ThreadID tid)
416{
417    unsigned reg_sel = (bankType[misc_reg] == perThreadContext)
418        ? tid : getVPENum(tid);
419    DPRINTF(MipsPRA, "Reading CP0 Register:%u Select:%u (%s) (%lx).\n",
420            misc_reg / 8, misc_reg % 8, miscRegNames[misc_reg],
421            miscRegFile[misc_reg][reg_sel]);
422    return miscRegFile[misc_reg][reg_sel];
423}
424
425//@TODO: MIPS MT's register view automatically connects
426//       Status to TCStatus depending on current thread
427//template <class TC>
428MiscReg
429ISA::readMiscReg(int misc_reg, ThreadContext *tc,  ThreadID tid)
430{
431    unsigned reg_sel = (bankType[misc_reg] == perThreadContext)
432        ? tid : getVPENum(tid);
433    DPRINTF(MipsPRA,
434            "Reading CP0 Register:%u Select:%u (%s) with effect (%lx).\n",
435            misc_reg / 8, misc_reg % 8, miscRegNames[misc_reg],
436            miscRegFile[misc_reg][reg_sel]);
437
438    return miscRegFile[misc_reg][reg_sel];
439}
440
441void
442ISA::setMiscRegNoEffect(int misc_reg, const MiscReg &val, ThreadID tid)
443{
444    unsigned reg_sel = (bankType[misc_reg] == perThreadContext)
445        ? tid : getVPENum(tid);
446    DPRINTF(MipsPRA,
447            "[tid:%i]: Setting (direct set) CP0 Register:%u "
448            "Select:%u (%s) to %#x.\n",
449            tid, misc_reg / 8, misc_reg % 8, miscRegNames[misc_reg], val);
450
451    miscRegFile[misc_reg][reg_sel] = val;
452}
453
454void
455ISA::setRegMask(int misc_reg, const MiscReg &val, ThreadID tid)
456{
457    unsigned reg_sel = (bankType[misc_reg] == perThreadContext)
458        ? tid : getVPENum(tid);
459    DPRINTF(MipsPRA,
460            "[tid:%i]: Setting CP0 Register: %u Select: %u (%s) to %#x\n",
461            tid, misc_reg / 8, misc_reg % 8, miscRegNames[misc_reg], val);
462    miscRegFile_WriteMask[misc_reg][reg_sel] = val;
463}
464
465// PROGRAMMER'S NOTES:
466// (1) Some CP0 Registers have fields that cannot
467// be overwritten. Make sure to handle those particular registers
468// with care!
469void
470ISA::setMiscReg(int misc_reg, const MiscReg &val,
471                    ThreadContext *tc, ThreadID tid)
472{
473    int reg_sel = (bankType[misc_reg] == perThreadContext)
474        ? tid : getVPENum(tid);
475
476    DPRINTF(MipsPRA,
477            "[tid:%i]: Setting CP0 Register:%u "
478            "Select:%u (%s) to %#x, with effect.\n",
479            tid, misc_reg / 8, misc_reg % 8, miscRegNames[misc_reg], val);
480
481    MiscReg cp0_val = filterCP0Write(misc_reg, reg_sel, val);
482
483    miscRegFile[misc_reg][reg_sel] = cp0_val;
484
485    scheduleCP0Update(tc->getCpuPtr(), 1);
486}
487
488/**
489 * This method doesn't need to adjust the Control Register Offset
490 * since it has already been done in the calling method
491 * (setRegWithEffect)
492*/
493MiscReg
494ISA::filterCP0Write(int misc_reg, int reg_sel, const MiscReg &val)
495{
496    MiscReg retVal = val;
497
498    // Mask off read-only regions
499    retVal &= miscRegFile_WriteMask[misc_reg][reg_sel];
500    MiscReg curVal = miscRegFile[misc_reg][reg_sel];
501    // Mask off current alue with inverse mask (clear writeable bits)
502    curVal &= (~miscRegFile_WriteMask[misc_reg][reg_sel]);
503    retVal |= curVal; // Combine the two
504    DPRINTF(MipsPRA,
505            "filterCP0Write: Mask: %lx, Inverse Mask: %lx, write Val: %x, "
506            "current val: %lx, written val: %x\n",
507            miscRegFile_WriteMask[misc_reg][reg_sel],
508            ~miscRegFile_WriteMask[misc_reg][reg_sel],
509            val, miscRegFile[misc_reg][reg_sel], retVal);
510    return retVal;
511}
512
513void
514ISA::scheduleCP0Update(BaseCPU *cpu, int delay)
515{
516    if (!cp0Updated) {
517        cp0Updated = true;
518
519        //schedule UPDATE
520        CP0Event *cp0_event = new CP0Event(this, cpu, UpdateCP0);
521        cpu->schedule(cp0_event, curTick() + cpu->ticks(delay));
522    }
523}
524
525void
526ISA::updateCPU(BaseCPU *cpu)
527{
528    ///////////////////////////////////////////////////////////////////
529    //
530    // EVALUATE CP0 STATE FOR MIPS MT
531    //
532    ///////////////////////////////////////////////////////////////////
533    MVPConf0Reg mvpConf0 = readMiscRegNoEffect(MISCREG_MVP_CONF0);
534    ThreadID num_threads = mvpConf0.ptc + 1;
535
536    for (ThreadID tid = 0; tid < num_threads; tid++) {
537        TCStatusReg tcStatus = readMiscRegNoEffect(MISCREG_TC_STATUS, tid);
538        TCHaltReg tcHalt = readMiscRegNoEffect(MISCREG_TC_HALT, tid);
539
540        //@todo: add vpe/mt check here thru mvpcontrol & vpecontrol regs
541        if (tcHalt.h == 1 || tcStatus.a == 0)  {
542            haltThread(cpu->getContext(tid));
543        } else if (tcHalt.h == 0 && tcStatus.a == 1) {
544            restoreThread(cpu->getContext(tid));
545        }
546    }
547
548    num_threads = mvpConf0.ptc + 1;
549
550    // Toggle update flag after we finished updating
551    cp0Updated = false;
552}
553
554ISA::CP0Event::CP0Event(CP0 *_cp0, BaseCPU *_cpu, CP0EventType e_type)
555    : Event(CPU_Tick_Pri), cp0(_cp0), cpu(_cpu), cp0EventType(e_type)
556{  }
557
558void
559ISA::CP0Event::process()
560{
561    switch (cp0EventType)
562    {
563      case UpdateCP0:
564        cp0->updateCPU(cpu);
565        break;
566    }
567}
568
569const char *
570ISA::CP0Event::description() const
571{
572    return "Coprocessor-0 event";
573}
574
575void
576ISA::CP0Event::scheduleEvent(int delay)
577{
578    cpu->reschedule(this, curTick() + cpu->ticks(delay), true);
579}
580
581void
582ISA::CP0Event::unscheduleEvent()
583{
584    if (scheduled())
585        squash();
586}
587
588}
589