1 /*
   2  * Copyright (c) 2002, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2012, 2018, SAP SE. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #ifndef CPU_PPC_VM_MACROASSEMBLER_PPC_HPP
  27 #define CPU_PPC_VM_MACROASSEMBLER_PPC_HPP
  28 
  29 #include "asm/assembler.hpp"
  30 #include "oops/accessDecorators.hpp"
  31 #include "runtime/rtmLocking.hpp"
  32 #include "utilities/macros.hpp"
  33 
  34 // MacroAssembler extends Assembler by a few frequently used macros.
  35 
  36 class ciTypeArray;
  37 
  38 class MacroAssembler: public Assembler {
  39  public:
  40   MacroAssembler(CodeBuffer* code) : Assembler(code) {}
  41 
  42   //
  43   // Optimized instruction emitters
  44   //
  45 
  46   inline static int largeoffset_si16_si16_hi(int si31) { return (si31 + (1<<15)) >> 16; }
  47   inline static int largeoffset_si16_si16_lo(int si31) { return si31 - (((si31 + (1<<15)) >> 16) << 16); }
  48 
  49   // load d = *[a+si31]
  50   // Emits several instructions if the offset is not encodable in one instruction.
  51   void ld_largeoffset_unchecked(Register d, int si31, Register a, int emit_filler_nop);
  52   void ld_largeoffset          (Register d, int si31, Register a, int emit_filler_nop);
  53   inline static bool is_ld_largeoffset(address a);
  54   inline static int get_ld_largeoffset_offset(address a);
  55 
  56   inline void round_to(Register r, int modulus);
  57 
  58   // Load/store with type given by parameter.
  59   void load_sized_value( Register dst, RegisterOrConstant offs, Register base, size_t size_in_bytes, bool is_signed);
  60   void store_sized_value(Register dst, RegisterOrConstant offs, Register base, size_t size_in_bytes);
  61 
  62   // Move register if destination register and target register are different
  63   inline void mr_if_needed(Register rd, Register rs);
  64   inline void fmr_if_needed(FloatRegister rd, FloatRegister rs);
  65   // This is dedicated for emitting scheduled mach nodes. For better
  66   // readability of the ad file I put it here.
  67   // Endgroups are not needed if
  68   //  - the scheduler is off
  69   //  - the scheduler found that there is a natural group end, in that
  70   //    case it reduced the size of the instruction used in the test
  71   //    yielding 'needed'.
  72   inline void endgroup_if_needed(bool needed);
  73 
  74   // Memory barriers.
  75   inline void membar(int bits);
  76   inline void release();
  77   inline void acquire();
  78   inline void fence();
  79 
  80   // nop padding
  81   void align(int modulus, int max = 252, int rem = 0);
  82 
  83   //
  84   // Constants, loading constants, TOC support
  85   //
  86 
  87   // Address of the global TOC.
  88   inline static address global_toc();
  89   // Offset of given address to the global TOC.
  90   inline static int offset_to_global_toc(const address addr);
  91 
  92   // Address of TOC of the current method.
  93   inline address method_toc();
  94   // Offset of given address to TOC of the current method.
  95   inline int offset_to_method_toc(const address addr);
  96 
  97   // Global TOC.
  98   void calculate_address_from_global_toc(Register dst, address addr,
  99                                          bool hi16 = true, bool lo16 = true,
 100                                          bool add_relocation = true, bool emit_dummy_addr = false);
 101   inline void calculate_address_from_global_toc_hi16only(Register dst, address addr) {
 102     calculate_address_from_global_toc(dst, addr, true, false);
 103   };
 104   inline void calculate_address_from_global_toc_lo16only(Register dst, address addr) {
 105     calculate_address_from_global_toc(dst, addr, false, true);
 106   };
 107 
 108   inline static bool is_calculate_address_from_global_toc_at(address a, address bound);
 109   // Returns address of first instruction in sequence.
 110   static address patch_calculate_address_from_global_toc_at(address a, address bound, address addr);
 111   static address get_address_of_calculate_address_from_global_toc_at(address a, address addr);
 112 
 113 #ifdef _LP64
 114   // Patch narrow oop constant.
 115   inline static bool is_set_narrow_oop(address a, address bound);
 116   // Returns address of first instruction in sequence.
 117   static address patch_set_narrow_oop(address a, address bound, narrowOop data);
 118   static narrowOop get_narrow_oop(address a, address bound);
 119 #endif
 120 
 121   inline static bool is_load_const_at(address a);
 122 
 123   // Emits an oop const to the constant pool, loads the constant, and
 124   // sets a relocation info with address current_pc.
 125   // Returns true if successful.
 126   bool load_const_from_method_toc(Register dst, AddressLiteral& a, Register toc, bool fixed_size = false);
 127 
 128   static bool is_load_const_from_method_toc_at(address a);
 129   static int get_offset_of_load_const_from_method_toc_at(address a);
 130 
 131   // Get the 64 bit constant from a `load_const' sequence.
 132   static long get_const(address load_const);
 133 
 134   // Patch the 64 bit constant of a `load_const' sequence. This is a
 135   // low level procedure. It neither flushes the instruction cache nor
 136   // is it atomic.
 137   static void patch_const(address load_const, long x);
 138 
 139   // Metadata in code that we have to keep track of.
 140   AddressLiteral allocate_metadata_address(Metadata* obj); // allocate_index
 141   AddressLiteral constant_metadata_address(Metadata* obj); // find_index
 142   // Oops used directly in compiled code are stored in the constant pool,
 143   // and loaded from there.
 144   // Allocate new entry for oop in constant pool. Generate relocation.
 145   AddressLiteral allocate_oop_address(jobject obj);
 146   // Find oop obj in constant pool. Return relocation with it's index.
 147   AddressLiteral constant_oop_address(jobject obj);
 148 
 149   // Find oop in constant pool and emit instructions to load it.
 150   // Uses constant_oop_address.
 151   inline void set_oop_constant(jobject obj, Register d);
 152   // Same as load_address.
 153   inline void set_oop         (AddressLiteral obj_addr, Register d);
 154 
 155   // Read runtime constant:  Issue load if constant not yet established,
 156   // else use real constant.
 157   virtual RegisterOrConstant delayed_value_impl(intptr_t* delayed_value_addr,
 158                                                 Register tmp,
 159                                                 int offset);
 160 
 161   //
 162   // branch, jump
 163   //
 164 
 165   inline void pd_patch_instruction(address branch, address target, const char* file, int line);
 166   NOT_PRODUCT(static void pd_print_patched_instruction(address branch);)
 167 
 168   // Conditional far branch for destinations encodable in 24+2 bits.
 169   // Same interface as bc, e.g. no inverse boint-field.
 170   enum {
 171     bc_far_optimize_not         = 0,
 172     bc_far_optimize_on_relocate = 1
 173   };
 174   // optimize: flag for telling the conditional far branch to optimize
 175   //           itself when relocated.
 176   void bc_far(int boint, int biint, Label& dest, int optimize);
 177   void bc_far_optimized(int boint, int biint, Label& dest); // 1 or 2 instructions
 178   // Relocation of conditional far branches.
 179   static bool    is_bc_far_at(address instruction_addr);
 180   static address get_dest_of_bc_far_at(address instruction_addr);
 181   static void    set_dest_of_bc_far_at(address instruction_addr, address dest);
 182  private:
 183   static bool inline is_bc_far_variant1_at(address instruction_addr);
 184   static bool inline is_bc_far_variant2_at(address instruction_addr);
 185   static bool inline is_bc_far_variant3_at(address instruction_addr);
 186  public:
 187 
 188   // Convenience bc_far versions.
 189   inline void blt_far(ConditionRegister crx, Label& L, int optimize);
 190   inline void bgt_far(ConditionRegister crx, Label& L, int optimize);
 191   inline void beq_far(ConditionRegister crx, Label& L, int optimize);
 192   inline void bso_far(ConditionRegister crx, Label& L, int optimize);
 193   inline void bge_far(ConditionRegister crx, Label& L, int optimize);
 194   inline void ble_far(ConditionRegister crx, Label& L, int optimize);
 195   inline void bne_far(ConditionRegister crx, Label& L, int optimize);
 196   inline void bns_far(ConditionRegister crx, Label& L, int optimize);
 197 
 198   // Emit, identify and patch a NOT mt-safe patchable 64 bit absolute call/jump.
 199  private:
 200   enum {
 201     bxx64_patchable_instruction_count = (2/*load_codecache_const*/ + 3/*5load_const*/ + 1/*mtctr*/ + 1/*bctrl*/),
 202     bxx64_patchable_size              = bxx64_patchable_instruction_count * BytesPerInstWord,
 203     bxx64_patchable_ret_addr_offset   = bxx64_patchable_size
 204   };
 205   void bxx64_patchable(address target, relocInfo::relocType rt, bool link);
 206   static bool is_bxx64_patchable_at(            address instruction_addr, bool link);
 207   // Does the instruction use a pc-relative encoding of the destination?
 208   static bool is_bxx64_patchable_pcrelative_at( address instruction_addr, bool link);
 209   static bool is_bxx64_patchable_variant1_at(   address instruction_addr, bool link);
 210   // Load destination relative to global toc.
 211   static bool is_bxx64_patchable_variant1b_at(  address instruction_addr, bool link);
 212   static bool is_bxx64_patchable_variant2_at(   address instruction_addr, bool link);
 213   static void set_dest_of_bxx64_patchable_at(   address instruction_addr, address target, bool link);
 214   static address get_dest_of_bxx64_patchable_at(address instruction_addr, bool link);
 215 
 216  public:
 217   // call
 218   enum {
 219     bl64_patchable_instruction_count = bxx64_patchable_instruction_count,
 220     bl64_patchable_size              = bxx64_patchable_size,
 221     bl64_patchable_ret_addr_offset   = bxx64_patchable_ret_addr_offset
 222   };
 223   inline void bl64_patchable(address target, relocInfo::relocType rt) {
 224     bxx64_patchable(target, rt, /*link=*/true);
 225   }
 226   inline static bool is_bl64_patchable_at(address instruction_addr) {
 227     return is_bxx64_patchable_at(instruction_addr, /*link=*/true);
 228   }
 229   inline static bool is_bl64_patchable_pcrelative_at(address instruction_addr) {
 230     return is_bxx64_patchable_pcrelative_at(instruction_addr, /*link=*/true);
 231   }
 232   inline static void set_dest_of_bl64_patchable_at(address instruction_addr, address target) {
 233     set_dest_of_bxx64_patchable_at(instruction_addr, target, /*link=*/true);
 234   }
 235   inline static address get_dest_of_bl64_patchable_at(address instruction_addr) {
 236     return get_dest_of_bxx64_patchable_at(instruction_addr, /*link=*/true);
 237   }
 238   // jump
 239   enum {
 240     b64_patchable_instruction_count = bxx64_patchable_instruction_count,
 241     b64_patchable_size              = bxx64_patchable_size,
 242   };
 243   inline void b64_patchable(address target, relocInfo::relocType rt) {
 244     bxx64_patchable(target, rt, /*link=*/false);
 245   }
 246   inline static bool is_b64_patchable_at(address instruction_addr) {
 247     return is_bxx64_patchable_at(instruction_addr, /*link=*/false);
 248   }
 249   inline static bool is_b64_patchable_pcrelative_at(address instruction_addr) {
 250     return is_bxx64_patchable_pcrelative_at(instruction_addr, /*link=*/false);
 251   }
 252   inline static void set_dest_of_b64_patchable_at(address instruction_addr, address target) {
 253     set_dest_of_bxx64_patchable_at(instruction_addr, target, /*link=*/false);
 254   }
 255   inline static address get_dest_of_b64_patchable_at(address instruction_addr) {
 256     return get_dest_of_bxx64_patchable_at(instruction_addr, /*link=*/false);
 257   }
 258 
 259   //
 260   // Support for frame handling
 261   //
 262 
 263   // some ABI-related functions
 264   void save_nonvolatile_gprs(   Register dst_base, int offset);
 265   void restore_nonvolatile_gprs(Register src_base, int offset);
 266   enum { num_volatile_regs = 11 + 14 }; // GPR + FPR
 267   void save_volatile_gprs(   Register dst_base, int offset);
 268   void restore_volatile_gprs(Register src_base, int offset);
 269   void save_LR_CR(   Register tmp);     // tmp contains LR on return.
 270   void restore_LR_CR(Register tmp);
 271 
 272   // Get current PC using bl-next-instruction trick.
 273   address get_PC_trash_LR(Register result);
 274 
 275   // Resize current frame either relatively wrt to current SP or absolute.
 276   void resize_frame(Register offset, Register tmp);
 277   void resize_frame(int      offset, Register tmp);
 278   void resize_frame_absolute(Register addr, Register tmp1, Register tmp2);
 279 
 280   // Push a frame of size bytes.
 281   void push_frame(Register bytes, Register tmp);
 282 
 283   // Push a frame of size `bytes'. No abi space provided.
 284   void push_frame(unsigned int bytes, Register tmp);
 285 
 286   // Push a frame of size `bytes' plus abi_reg_args on top.
 287   void push_frame_reg_args(unsigned int bytes, Register tmp);
 288 
 289   // Setup up a new C frame with a spill area for non-volatile GPRs and additional
 290   // space for local variables
 291   void push_frame_reg_args_nonvolatiles(unsigned int bytes, Register tmp);
 292 
 293   // pop current C frame
 294   void pop_frame();
 295 
 296   //
 297   // Calls
 298   //
 299 
 300  private:
 301   address _last_calls_return_pc;
 302 
 303 #if defined(ABI_ELFv2)
 304   // Generic version of a call to C function.
 305   // Updates and returns _last_calls_return_pc.
 306   address branch_to(Register function_entry, bool and_link);
 307 #else
 308   // Generic version of a call to C function via a function descriptor
 309   // with variable support for C calling conventions (TOC, ENV, etc.).
 310   // updates and returns _last_calls_return_pc.
 311   address branch_to(Register function_descriptor, bool and_link, bool save_toc_before_call,
 312                     bool restore_toc_after_call, bool load_toc_of_callee, bool load_env_of_callee);
 313 #endif
 314 
 315  public:
 316 
 317   // Get the pc where the last call will return to. returns _last_calls_return_pc.
 318   inline address last_calls_return_pc();
 319 
 320 #if defined(ABI_ELFv2)
 321   // Call a C function via a function descriptor and use full C
 322   // calling conventions. Updates and returns _last_calls_return_pc.
 323   address call_c(Register function_entry);
 324   // For tail calls: only branch, don't link, so callee returns to caller of this function.
 325   address call_c_and_return_to_caller(Register function_entry);
 326   address call_c(address function_entry, relocInfo::relocType rt);
 327 #else
 328   // Call a C function via a function descriptor and use full C
 329   // calling conventions. Updates and returns _last_calls_return_pc.
 330   address call_c(Register function_descriptor);
 331   // For tail calls: only branch, don't link, so callee returns to caller of this function.
 332   address call_c_and_return_to_caller(Register function_descriptor);
 333   address call_c(const FunctionDescriptor* function_descriptor, relocInfo::relocType rt);
 334   address call_c_using_toc(const FunctionDescriptor* function_descriptor, relocInfo::relocType rt,
 335                            Register toc);
 336 #endif
 337 
 338  protected:
 339 
 340   // It is imperative that all calls into the VM are handled via the
 341   // call_VM macros. They make sure that the stack linkage is setup
 342   // correctly. call_VM's correspond to ENTRY/ENTRY_X entry points
 343   // while call_VM_leaf's correspond to LEAF entry points.
 344   //
 345   // This is the base routine called by the different versions of
 346   // call_VM. The interpreter may customize this version by overriding
 347   // it for its purposes (e.g., to save/restore additional registers
 348   // when doing a VM call).
 349   //
 350   // If no last_java_sp is specified (noreg) then SP will be used instead.
 351   virtual void call_VM_base(
 352      // where an oop-result ends up if any; use noreg otherwise
 353     Register        oop_result,
 354     // to set up last_Java_frame in stubs; use noreg otherwise
 355     Register        last_java_sp,
 356     // the entry point
 357     address         entry_point,
 358     // flag which indicates if exception should be checked
 359     bool            check_exception = true
 360   );
 361 
 362   // Support for VM calls. This is the base routine called by the
 363   // different versions of call_VM_leaf. The interpreter may customize
 364   // this version by overriding it for its purposes (e.g., to
 365   // save/restore additional registers when doing a VM call).
 366   void call_VM_leaf_base(address entry_point);
 367 
 368  public:
 369   // Call into the VM.
 370   // Passes the thread pointer (in R3_ARG1) as a prepended argument.
 371   // Makes sure oop return values are visible to the GC.
 372   void call_VM(Register oop_result, address entry_point, bool check_exceptions = true);
 373   void call_VM(Register oop_result, address entry_point, Register arg_1, bool check_exceptions = true);
 374   void call_VM(Register oop_result, address entry_point, Register arg_1, Register arg_2, bool check_exceptions = true);
 375   void call_VM(Register oop_result, address entry_point, Register arg_1, Register arg_2, Register arg3, bool check_exceptions = true);
 376   void call_VM_leaf(address entry_point);
 377   void call_VM_leaf(address entry_point, Register arg_1);
 378   void call_VM_leaf(address entry_point, Register arg_1, Register arg_2);
 379   void call_VM_leaf(address entry_point, Register arg_1, Register arg_2, Register arg_3);
 380 
 381   // Call a stub function via a function descriptor, but don't save
 382   // TOC before call, don't setup TOC and ENV for call, and don't
 383   // restore TOC after call. Updates and returns _last_calls_return_pc.
 384   inline address call_stub(Register function_entry);
 385   inline void call_stub_and_return_to(Register function_entry, Register return_pc);
 386 
 387   //
 388   // Java utilities
 389   //
 390 
 391   // Read from the polling page, its address is already in a register.
 392   inline void load_from_polling_page(Register polling_page_address, int offset = 0);
 393   // Check whether instruction is a read access to the polling page
 394   // which was emitted by load_from_polling_page(..).
 395   static bool is_load_from_polling_page(int instruction, void* ucontext/*may be NULL*/,
 396                                         address* polling_address_ptr = NULL);
 397 
 398   // Check whether instruction is a write access to the memory
 399   // serialization page realized by one of the instructions stw, stwu,
 400   // stwx, or stwux.
 401   static bool is_memory_serialization(int instruction, JavaThread* thread, void* ucontext);
 402 
 403   // Support for NULL-checks
 404   //
 405   // Generates code that causes a NULL OS exception if the content of reg is NULL.
 406   // If the accessed location is M[reg + offset] and the offset is known, provide the
 407   // offset. No explicit code generation is needed if the offset is within a certain
 408   // range (0 <= offset <= page_size).
 409 
 410   // Stack overflow checking
 411   void bang_stack_with_offset(int offset);
 412 
 413   // If instruction is a stack bang of the form ld, stdu, or
 414   // stdux, return the banged address. Otherwise, return 0.
 415   static address get_stack_bang_address(int instruction, void* ucontext);
 416 
 417   // Check for reserved stack access in method being exited. If the reserved
 418   // stack area was accessed, protect it again and throw StackOverflowError.
 419   void reserved_stack_check(Register return_pc);
 420 
 421   // Atomics
 422   // CmpxchgX sets condition register to cmpX(current, compare).
 423   // (flag == ne) => (dest_current_value != compare_value), (!swapped)
 424   // (flag == eq) => (dest_current_value == compare_value), ( swapped)
 425   static inline bool cmpxchgx_hint_acquire_lock()  { return true; }
 426   // The stxcx will probably not be succeeded by a releasing store.
 427   static inline bool cmpxchgx_hint_release_lock()  { return false; }
 428   static inline bool cmpxchgx_hint_atomic_update() { return false; }
 429 
 430   // Cmpxchg semantics
 431   enum {
 432     MemBarNone = 0,
 433     MemBarRel  = 1,
 434     MemBarAcq  = 2,
 435     MemBarFenceAfter = 4 // use powers of 2
 436   };
 437  private:
 438   // Helper functions for word/sub-word atomics.
 439   void atomic_get_and_modify_generic(Register dest_current_value, Register exchange_value,
 440                                      Register addr_base, Register tmp1, Register tmp2, Register tmp3,
 441                                      bool cmpxchgx_hint, bool is_add, int size);
 442   void cmpxchg_loop_body(ConditionRegister flag, Register dest_current_value,
 443                          Register compare_value, Register exchange_value,
 444                          Register addr_base, Register tmp1, Register tmp2,
 445                          Label &retry, Label &failed, bool cmpxchgx_hint, int size);
 446   void cmpxchg_generic(ConditionRegister flag,
 447                        Register dest_current_value, Register compare_value, Register exchange_value, Register addr_base,
 448                        Register tmp1, Register tmp2,
 449                        int semantics, bool cmpxchgx_hint, Register int_flag_success, bool contention_hint, bool weak, int size);
 450  public:
 451   // Temps and addr_base are killed if processor does not support Power 8 instructions.
 452   // Result will be sign extended.
 453   void getandsetb(Register dest_current_value, Register exchange_value, Register addr_base,
 454                   Register tmp1, Register tmp2, Register tmp3, bool cmpxchgx_hint) {
 455     atomic_get_and_modify_generic(dest_current_value, exchange_value, addr_base, tmp1, tmp2, tmp3, cmpxchgx_hint, false, 1);
 456   }
 457   // Temps and addr_base are killed if processor does not support Power 8 instructions.
 458   // Result will be sign extended.
 459   void getandseth(Register dest_current_value, Register exchange_value, Register addr_base,
 460                   Register tmp1, Register tmp2, Register tmp3, bool cmpxchgx_hint) {
 461     atomic_get_and_modify_generic(dest_current_value, exchange_value, addr_base, tmp1, tmp2, tmp3, cmpxchgx_hint, false, 2);
 462   }
 463   void getandsetw(Register dest_current_value, Register exchange_value, Register addr_base,
 464                   bool cmpxchgx_hint) {
 465     atomic_get_and_modify_generic(dest_current_value, exchange_value, addr_base, noreg, noreg, noreg, cmpxchgx_hint, false, 4);
 466   }
 467   void getandsetd(Register dest_current_value, Register exchange_value, Register addr_base,
 468                   bool cmpxchgx_hint);
 469   // tmp2/3 and addr_base are killed if processor does not support Power 8 instructions (tmp1 is always needed).
 470   // Result will be sign extended.
 471   void getandaddb(Register dest_current_value, Register inc_value, Register addr_base,
 472                   Register tmp1, Register tmp2, Register tmp3, bool cmpxchgx_hint) {
 473     atomic_get_and_modify_generic(dest_current_value, inc_value, addr_base, tmp1, tmp2, tmp3, cmpxchgx_hint, true, 1);
 474   }
 475   // tmp2/3 and addr_base are killed if processor does not support Power 8 instructions (tmp1 is always needed).
 476   // Result will be sign extended.
 477   void getandaddh(Register dest_current_value, Register inc_value, Register addr_base,
 478                   Register tmp1, Register tmp2, Register tmp3, bool cmpxchgx_hint) {
 479     atomic_get_and_modify_generic(dest_current_value, inc_value, addr_base, tmp1, tmp2, tmp3, cmpxchgx_hint, true, 2);
 480   }
 481   void getandaddw(Register dest_current_value, Register inc_value, Register addr_base,
 482                   Register tmp1, bool cmpxchgx_hint) {
 483     atomic_get_and_modify_generic(dest_current_value, inc_value, addr_base, tmp1, noreg, noreg, cmpxchgx_hint, true, 4);
 484   }
 485   void getandaddd(Register dest_current_value, Register exchange_value, Register addr_base,
 486                   Register tmp, bool cmpxchgx_hint);
 487   // Temps, addr_base and exchange_value are killed if processor does not support Power 8 instructions.
 488   // compare_value must be at least 32 bit sign extended. Result will be sign extended.
 489   void cmpxchgb(ConditionRegister flag,
 490                 Register dest_current_value, Register compare_value, Register exchange_value, Register addr_base,
 491                 Register tmp1, Register tmp2, int semantics, bool cmpxchgx_hint = false,
 492                 Register int_flag_success = noreg, bool contention_hint = false, bool weak = false) {
 493     cmpxchg_generic(flag, dest_current_value, compare_value, exchange_value, addr_base, tmp1, tmp2,
 494                     semantics, cmpxchgx_hint, int_flag_success, contention_hint, weak, 1);
 495   }
 496   // Temps, addr_base and exchange_value are killed if processor does not support Power 8 instructions.
 497   // compare_value must be at least 32 bit sign extended. Result will be sign extended.
 498   void cmpxchgh(ConditionRegister flag,
 499                 Register dest_current_value, Register compare_value, Register exchange_value, Register addr_base,
 500                 Register tmp1, Register tmp2, int semantics, bool cmpxchgx_hint = false,
 501                 Register int_flag_success = noreg, bool contention_hint = false, bool weak = false) {
 502     cmpxchg_generic(flag, dest_current_value, compare_value, exchange_value, addr_base, tmp1, tmp2,
 503                     semantics, cmpxchgx_hint, int_flag_success, contention_hint, weak, 2);
 504   }
 505   void cmpxchgw(ConditionRegister flag,
 506                 Register dest_current_value, Register compare_value, Register exchange_value, Register addr_base,
 507                 int semantics, bool cmpxchgx_hint = false,
 508                 Register int_flag_success = noreg, bool contention_hint = false, bool weak = false) {
 509     cmpxchg_generic(flag, dest_current_value, compare_value, exchange_value, addr_base, noreg, noreg,
 510                     semantics, cmpxchgx_hint, int_flag_success, contention_hint, weak, 4);
 511   }
 512   void cmpxchgd(ConditionRegister flag,
 513                 Register dest_current_value, RegisterOrConstant compare_value, Register exchange_value,
 514                 Register addr_base, int semantics, bool cmpxchgx_hint = false,
 515                 Register int_flag_success = noreg, Label* failed = NULL, bool contention_hint = false, bool weak = false);
 516 
 517   // interface method calling
 518   void lookup_interface_method(Register recv_klass,
 519                                Register intf_klass,
 520                                RegisterOrConstant itable_index,
 521                                Register method_result,
 522                                Register temp_reg, Register temp2_reg,
 523                                Label& no_such_interface,
 524                                bool return_method = true);
 525 
 526   // virtual method calling
 527   void lookup_virtual_method(Register recv_klass,
 528                              RegisterOrConstant vtable_index,
 529                              Register method_result);
 530 
 531   // Test sub_klass against super_klass, with fast and slow paths.
 532 
 533   // The fast path produces a tri-state answer: yes / no / maybe-slow.
 534   // One of the three labels can be NULL, meaning take the fall-through.
 535   // If super_check_offset is -1, the value is loaded up from super_klass.
 536   // No registers are killed, except temp_reg and temp2_reg.
 537   // If super_check_offset is not -1, temp2_reg is not used and can be noreg.
 538   void check_klass_subtype_fast_path(Register sub_klass,
 539                                      Register super_klass,
 540                                      Register temp1_reg,
 541                                      Register temp2_reg,
 542                                      Label* L_success,
 543                                      Label* L_failure,
 544                                      Label* L_slow_path = NULL, // default fall through
 545                                      RegisterOrConstant super_check_offset = RegisterOrConstant(-1));
 546 
 547   // The rest of the type check; must be wired to a corresponding fast path.
 548   // It does not repeat the fast path logic, so don't use it standalone.
 549   // The temp_reg can be noreg, if no temps are available.
 550   // It can also be sub_klass or super_klass, meaning it's OK to kill that one.
 551   // Updates the sub's secondary super cache as necessary.
 552   void check_klass_subtype_slow_path(Register sub_klass,
 553                                      Register super_klass,
 554                                      Register temp1_reg,
 555                                      Register temp2_reg,
 556                                      Label* L_success = NULL,
 557                                      Register result_reg = noreg);
 558 
 559   // Simplified, combined version, good for typical uses.
 560   // Falls through on failure.
 561   void check_klass_subtype(Register sub_klass,
 562                            Register super_klass,
 563                            Register temp1_reg,
 564                            Register temp2_reg,
 565                            Label& L_success);
 566 
 567   // Method handle support (JSR 292).
 568   void check_method_handle_type(Register mtype_reg, Register mh_reg, Register temp_reg, Label& wrong_method_type);
 569 
 570   RegisterOrConstant argument_offset(RegisterOrConstant arg_slot, Register temp_reg, int extra_slot_offset = 0);
 571 
 572   // Biased locking support
 573   // Upon entry,obj_reg must contain the target object, and mark_reg
 574   // must contain the target object's header.
 575   // Destroys mark_reg if an attempt is made to bias an anonymously
 576   // biased lock. In this case a failure will go either to the slow
 577   // case or fall through with the notEqual condition code set with
 578   // the expectation that the slow case in the runtime will be called.
 579   // In the fall-through case where the CAS-based lock is done,
 580   // mark_reg is not destroyed.
 581   void biased_locking_enter(ConditionRegister cr_reg, Register obj_reg, Register mark_reg, Register temp_reg,
 582                             Register temp2_reg, Label& done, Label* slow_case = NULL);
 583   // Upon entry, the base register of mark_addr must contain the oop.
 584   // Destroys temp_reg.
 585   // If allow_delay_slot_filling is set to true, the next instruction
 586   // emitted after this one will go in an annulled delay slot if the
 587   // biased locking exit case failed.
 588   void biased_locking_exit(ConditionRegister cr_reg, Register mark_addr, Register temp_reg, Label& done);
 589 
 590   // allocation (for C1)
 591   void eden_allocate(
 592     Register obj,                      // result: pointer to object after successful allocation
 593     Register var_size_in_bytes,        // object size in bytes if unknown at compile time; invalid otherwise
 594     int      con_size_in_bytes,        // object size in bytes if   known at compile time
 595     Register t1,                       // temp register
 596     Register t2,                       // temp register
 597     Label&   slow_case                 // continuation point if fast allocation fails
 598   );
 599   void tlab_allocate(
 600     Register obj,                      // result: pointer to object after successful allocation
 601     Register var_size_in_bytes,        // object size in bytes if unknown at compile time; invalid otherwise
 602     int      con_size_in_bytes,        // object size in bytes if   known at compile time
 603     Register t1,                       // temp register
 604     Label&   slow_case                 // continuation point if fast allocation fails
 605   );
 606   void incr_allocated_bytes(RegisterOrConstant size_in_bytes, Register t1, Register t2);
 607 
 608   enum { trampoline_stub_size = 6 * 4 };
 609   address emit_trampoline_stub(int destination_toc_offset, int insts_call_instruction_offset, Register Rtoc = noreg);
 610 
 611   void atomic_inc_ptr(Register addr, Register result, int simm16 = 1);
 612   void atomic_ori_int(Register addr, Register result, int uimm16);
 613 
 614 #if INCLUDE_RTM_OPT
 615   void rtm_counters_update(Register abort_status, Register rtm_counters);
 616   void branch_on_random_using_tb(Register tmp, int count, Label& brLabel);
 617   void rtm_abort_ratio_calculation(Register rtm_counters_reg, RTMLockingCounters* rtm_counters,
 618                                    Metadata* method_data);
 619   void rtm_profiling(Register abort_status_Reg, Register temp_Reg,
 620                      RTMLockingCounters* rtm_counters, Metadata* method_data, bool profile_rtm);
 621   void rtm_retry_lock_on_abort(Register retry_count, Register abort_status,
 622                                Label& retryLabel, Label* checkRetry = NULL);
 623   void rtm_retry_lock_on_busy(Register retry_count, Register owner_addr, Label& retryLabel);
 624   void rtm_stack_locking(ConditionRegister flag, Register obj, Register mark_word, Register tmp,
 625                          Register retry_on_abort_count,
 626                          RTMLockingCounters* stack_rtm_counters,
 627                          Metadata* method_data, bool profile_rtm,
 628                          Label& DONE_LABEL, Label& IsInflated);
 629   void rtm_inflated_locking(ConditionRegister flag, Register obj, Register mark_word, Register box,
 630                             Register retry_on_busy_count, Register retry_on_abort_count,
 631                             RTMLockingCounters* rtm_counters,
 632                             Metadata* method_data, bool profile_rtm,
 633                             Label& DONE_LABEL);
 634 #endif
 635 
 636   void compiler_fast_lock_object(ConditionRegister flag, Register oop, Register box,
 637                                  Register tmp1, Register tmp2, Register tmp3,
 638                                  bool try_bias = UseBiasedLocking,
 639                                  RTMLockingCounters* rtm_counters = NULL,
 640                                  RTMLockingCounters* stack_rtm_counters = NULL,
 641                                  Metadata* method_data = NULL,
 642                                  bool use_rtm = false, bool profile_rtm = false);
 643 
 644   void compiler_fast_unlock_object(ConditionRegister flag, Register oop, Register box,
 645                                    Register tmp1, Register tmp2, Register tmp3,
 646                                    bool try_bias = UseBiasedLocking, bool use_rtm = false);
 647 
 648   // Support for serializing memory accesses between threads
 649   void serialize_memory(Register thread, Register tmp1, Register tmp2);
 650 
 651   // Check if safepoint requested and if so branch
 652   void safepoint_poll(Label& slow_path, Register temp_reg);
 653 
 654   void resolve_jobject(Register value, Register tmp1, Register tmp2, bool needs_frame);
 655 
 656   // Support for managing the JavaThread pointer (i.e.; the reference to
 657   // thread-local information).
 658 
 659   // Support for last Java frame (but use call_VM instead where possible):
 660   // access R16_thread->last_Java_sp.
 661   void set_last_Java_frame(Register last_java_sp, Register last_Java_pc);
 662   void reset_last_Java_frame(void);
 663   void set_top_ijava_frame_at_SP_as_last_Java_frame(Register sp, Register tmp1);
 664 
 665   // Read vm result from thread: oop_result = R16_thread->result;
 666   void get_vm_result  (Register oop_result);
 667   void get_vm_result_2(Register metadata_result);
 668 
 669   static bool needs_explicit_null_check(intptr_t offset);
 670   static bool uses_implicit_null_check(void* address);
 671 
 672   // Trap-instruction-based checks.
 673   // Range checks can be distinguished from zero checks as they check 32 bit,
 674   // zero checks all 64 bits (tw, td).
 675   inline void trap_null_check(Register a, trap_to_bits cmp = traptoEqual);
 676   static bool is_trap_null_check(int x) {
 677     return is_tdi(x, traptoEqual,               -1/*any reg*/, 0) ||
 678            is_tdi(x, traptoGreaterThanUnsigned, -1/*any reg*/, 0);
 679   }
 680 
 681   inline void trap_zombie_not_entrant();
 682   static bool is_trap_zombie_not_entrant(int x) { return is_tdi(x, traptoUnconditional, 0/*reg 0*/, 1); }
 683 
 684   inline void trap_should_not_reach_here();
 685   static bool is_trap_should_not_reach_here(int x) { return is_tdi(x, traptoUnconditional, 0/*reg 0*/, 2); }
 686 
 687   inline void trap_ic_miss_check(Register a, Register b);
 688   static bool is_trap_ic_miss_check(int x) {
 689     return is_td(x, traptoGreaterThanUnsigned | traptoLessThanUnsigned, -1/*any reg*/, -1/*any reg*/);
 690   }
 691 
 692   // Implicit or explicit null check, jumps to static address exception_entry.
 693   inline void null_check_throw(Register a, int offset, Register temp_reg, address exception_entry);
 694   inline void null_check(Register a, int offset, Label *Lis_null); // implicit only if Lis_null not provided
 695 
 696   // Access heap oop, handle encoding and GC barriers.
 697   // Some GC barriers call C so use needs_frame = true if an extra frame is needed at the current call site.
 698  private:
 699   inline void access_store_at(BasicType type, DecoratorSet decorators,
 700                               Register base, RegisterOrConstant ind_or_offs, Register val,
 701                               Register tmp1, Register tmp2, Register tmp3, bool needs_frame);
 702   inline void access_load_at(BasicType type, DecoratorSet decorators,
 703                              Register base, RegisterOrConstant ind_or_offs, Register dst,
 704                              Register tmp1, Register tmp2, bool needs_frame, Label *L_handle_null = NULL);
 705 
 706  public:
 707   // Specify tmp1 for better code in certain compressed oops cases. Specify Label to bail out on null oop.
 708   // tmp1, tmp2 and needs_frame are used with decorators ON_PHANTOM_OOP_REF or ON_WEAK_OOP_REF.
 709   inline void load_heap_oop(Register d, RegisterOrConstant offs, Register s1,
 710                             Register tmp1, Register tmp2, bool needs_frame,
 711                             DecoratorSet decorators = 0, Label *L_handle_null = NULL);
 712 
 713   inline void store_heap_oop(Register d, RegisterOrConstant offs, Register s1,
 714                              Register tmp1, Register tmp2, Register tmp3, bool needs_frame,
 715                              DecoratorSet decorators = 0);
 716 
 717   // Encode/decode heap oop. Oop may not be null, else en/decoding goes wrong.
 718   // src == d allowed.
 719   inline Register encode_heap_oop_not_null(Register d, Register src = noreg);
 720   inline Register decode_heap_oop_not_null(Register d, Register src = noreg);
 721 
 722   // Null allowed.
 723   inline Register encode_heap_oop(Register d, Register src); // Prefer null check in GC barrier!
 724   inline void decode_heap_oop(Register d);
 725 
 726   // Load/Store klass oop from klass field. Compress.
 727   void load_klass(Register dst, Register src);
 728   void store_klass(Register dst_oop, Register klass, Register tmp = R0);
 729   void store_klass_gap(Register dst_oop, Register val = noreg); // Will store 0 if val not specified.
 730 
 731   void resolve_oop_handle(Register result);
 732   void load_mirror_from_const_method(Register mirror, Register const_method);
 733 
 734   static int instr_size_for_decode_klass_not_null();
 735   void decode_klass_not_null(Register dst, Register src = noreg);
 736   Register encode_klass_not_null(Register dst, Register src = noreg);
 737 
 738   // SIGTRAP-based range checks for arrays.
 739   inline void trap_range_check_l(Register a, Register b);
 740   inline void trap_range_check_l(Register a, int si16);
 741   static bool is_trap_range_check_l(int x) {
 742     return (is_tw (x, traptoLessThanUnsigned, -1/*any reg*/, -1/*any reg*/) ||
 743             is_twi(x, traptoLessThanUnsigned, -1/*any reg*/)                  );
 744   }
 745   inline void trap_range_check_le(Register a, int si16);
 746   static bool is_trap_range_check_le(int x) {
 747     return is_twi(x, traptoEqual | traptoLessThanUnsigned, -1/*any reg*/);
 748   }
 749   inline void trap_range_check_g(Register a, int si16);
 750   static bool is_trap_range_check_g(int x) {
 751     return is_twi(x, traptoGreaterThanUnsigned, -1/*any reg*/);
 752   }
 753   inline void trap_range_check_ge(Register a, Register b);
 754   inline void trap_range_check_ge(Register a, int si16);
 755   static bool is_trap_range_check_ge(int x) {
 756     return (is_tw (x, traptoEqual | traptoGreaterThanUnsigned, -1/*any reg*/, -1/*any reg*/) ||
 757             is_twi(x, traptoEqual | traptoGreaterThanUnsigned, -1/*any reg*/)                  );
 758   }
 759   static bool is_trap_range_check(int x) {
 760     return is_trap_range_check_l(x) || is_trap_range_check_le(x) ||
 761            is_trap_range_check_g(x) || is_trap_range_check_ge(x);
 762   }
 763 
 764   void clear_memory_unrolled(Register base_ptr, int cnt_dwords, Register tmp = R0, int offset = 0);
 765   void clear_memory_constlen(Register base_ptr, int cnt_dwords, Register tmp = R0);
 766   void clear_memory_doubleword(Register base_ptr, Register cnt_dwords, Register tmp = R0, long const_cnt = -1);
 767 
 768 #ifdef COMPILER2
 769   // Intrinsics for CompactStrings
 770   // Compress char[] to byte[] by compressing 16 bytes at once.
 771   void string_compress_16(Register src, Register dst, Register cnt,
 772                           Register tmp1, Register tmp2, Register tmp3, Register tmp4, Register tmp5,
 773                           Label& Lfailure);
 774 
 775   // Compress char[] to byte[]. cnt must be positive int.
 776   void string_compress(Register src, Register dst, Register cnt, Register tmp, Label& Lfailure);
 777 
 778   // Inflate byte[] to char[] by inflating 16 bytes at once.
 779   void string_inflate_16(Register src, Register dst, Register cnt,
 780                          Register tmp1, Register tmp2, Register tmp3, Register tmp4, Register tmp5);
 781 
 782   // Inflate byte[] to char[]. cnt must be positive int.
 783   void string_inflate(Register src, Register dst, Register cnt, Register tmp);
 784 
 785   void string_compare(Register str1, Register str2, Register cnt1, Register cnt2,
 786                       Register tmp1, Register result, int ae);
 787 
 788   void array_equals(bool is_array_equ, Register ary1, Register ary2,
 789                     Register limit, Register tmp1, Register result, bool is_byte);
 790 
 791   void string_indexof(Register result, Register haystack, Register haycnt,
 792                       Register needle, ciTypeArray* needle_values, Register needlecnt, int needlecntval,
 793                       Register tmp1, Register tmp2, Register tmp3, Register tmp4, int ae);
 794 
 795   void string_indexof_char(Register result, Register haystack, Register haycnt,
 796                            Register needle, jchar needleChar, Register tmp1, Register tmp2, bool is_byte);
 797 
 798   void has_negatives(Register src, Register cnt, Register result, Register tmp1, Register tmp2);
 799 #endif
 800 
 801   // Emitters for BigInteger.multiplyToLen intrinsic.
 802   inline void multiply64(Register dest_hi, Register dest_lo,
 803                          Register x, Register y);
 804   void add2_with_carry(Register dest_hi, Register dest_lo,
 805                        Register src1, Register src2);
 806   void multiply_64_x_64_loop(Register x, Register xstart, Register x_xstart,
 807                              Register y, Register y_idx, Register z,
 808                              Register carry, Register product_high, Register product,
 809                              Register idx, Register kdx, Register tmp);
 810   void multiply_add_128_x_128(Register x_xstart, Register y, Register z,
 811                               Register yz_idx, Register idx, Register carry,
 812                               Register product_high, Register product, Register tmp,
 813                               int offset);
 814   void multiply_128_x_128_loop(Register x_xstart,
 815                                Register y, Register z,
 816                                Register yz_idx, Register idx, Register carry,
 817                                Register product_high, Register product,
 818                                Register carry2, Register tmp);
 819   void muladd(Register out, Register in, Register offset, Register len, Register k,
 820               Register tmp1, Register tmp2, Register carry);
 821   void multiply_to_len(Register x, Register xlen,
 822                        Register y, Register ylen,
 823                        Register z, Register zlen,
 824                        Register tmp1, Register tmp2, Register tmp3, Register tmp4, Register tmp5,
 825                        Register tmp6, Register tmp7, Register tmp8, Register tmp9, Register tmp10,
 826                        Register tmp11, Register tmp12, Register tmp13);
 827 
 828   // Emitters for CRC32 calculation.
 829   // A note on invertCRC:
 830   //   Unfortunately, internal representation of crc differs between CRC32 and CRC32C.
 831   //   CRC32 holds it's current crc value in the externally visible representation.
 832   //   CRC32C holds it's current crc value in internal format, ready for updating.
 833   //   Thus, the crc value must be bit-flipped before updating it in the CRC32 case.
 834   //   In the CRC32C case, it must be bit-flipped when it is given to the outside world (getValue()).
 835   //   The bool invertCRC parameter indicates whether bit-flipping is required before updates.
 836   void load_reverse_32(Register dst, Register src);
 837   int  crc32_table_columns(Register table, Register tc0, Register tc1, Register tc2, Register tc3);
 838   void fold_byte_crc32(Register crc, Register val, Register table, Register tmp);
 839   void fold_8bit_crc32(Register crc, Register table, Register tmp);
 840   void update_byte_crc32(Register crc, Register val, Register table);
 841   void update_byteLoop_crc32(Register crc, Register buf, Register len, Register table,
 842                              Register data, bool loopAlignment);
 843   void update_1word_crc32(Register crc, Register buf, Register table, int bufDisp, int bufInc,
 844                           Register t0,  Register t1,  Register t2,  Register t3,
 845                           Register tc0, Register tc1, Register tc2, Register tc3);
 846   void kernel_crc32_2word(Register crc, Register buf, Register len, Register table,
 847                           Register t0,  Register t1,  Register t2,  Register t3,
 848                           Register tc0, Register tc1, Register tc2, Register tc3,
 849                           bool invertCRC);
 850   void kernel_crc32_1word(Register crc, Register buf, Register len, Register table,
 851                           Register t0,  Register t1,  Register t2,  Register t3,
 852                           Register tc0, Register tc1, Register tc2, Register tc3,
 853                           bool invertCRC);
 854   void kernel_crc32_1byte(Register crc, Register buf, Register len, Register table,
 855                           Register t0,  Register t1,  Register t2,  Register t3,
 856                           bool invertCRC);
 857   void kernel_crc32_1word_vpmsum(Register crc, Register buf, Register len, Register table,
 858                           Register constants, Register barretConstants,
 859                           Register t0,  Register t1, Register t2, Register t3, Register t4,
 860                           bool invertCRC);
 861   void kernel_crc32_1word_aligned(Register crc, Register buf, Register len,
 862                           Register constants, Register barretConstants,
 863                           Register t0, Register t1, Register t2, Register t3, Register t4);
 864 
 865   void kernel_crc32_singleByte(Register crc, Register buf, Register len, Register table, Register tmp,
 866                                bool invertCRC);
 867   void kernel_crc32_singleByteReg(Register crc, Register val, Register table,
 868                                   bool invertCRC);
 869 
 870   // SHA-2 auxiliary functions and public interfaces
 871  private:
 872   void sha256_deque(const VectorRegister src,
 873       const VectorRegister dst1, const VectorRegister dst2, const VectorRegister dst3);
 874   void sha256_load_h_vec(const VectorRegister a, const VectorRegister e, const Register hptr);
 875   void sha256_round(const VectorRegister* hs, const int total_hs, int& h_cnt, const VectorRegister kpw);
 876   void sha256_load_w_plus_k_vec(const Register buf_in, const VectorRegister* ws,
 877       const int total_ws, const Register k, const VectorRegister* kpws,
 878       const int total_kpws);
 879   void sha256_calc_4w(const VectorRegister w0, const VectorRegister w1,
 880       const VectorRegister w2, const VectorRegister w3, const VectorRegister kpw0,
 881       const VectorRegister kpw1, const VectorRegister kpw2, const VectorRegister kpw3,
 882       const Register j, const Register k);
 883   void sha256_update_sha_state(const VectorRegister a, const VectorRegister b,
 884       const VectorRegister c, const VectorRegister d, const VectorRegister e,
 885       const VectorRegister f, const VectorRegister g, const VectorRegister h,
 886       const Register hptr);
 887 
 888   void sha512_load_w_vec(const Register buf_in, const VectorRegister* ws, const int total_ws);
 889   void sha512_update_sha_state(const Register state, const VectorRegister* hs, const int total_hs);
 890   void sha512_round(const VectorRegister* hs, const int total_hs, int& h_cnt, const VectorRegister kpw);
 891   void sha512_load_h_vec(const Register state, const VectorRegister* hs, const int total_hs);
 892   void sha512_calc_2w(const VectorRegister w0, const VectorRegister w1,
 893       const VectorRegister w2, const VectorRegister w3,
 894       const VectorRegister w4, const VectorRegister w5,
 895       const VectorRegister w6, const VectorRegister w7,
 896       const VectorRegister kpw0, const VectorRegister kpw1, const Register j,
 897       const VectorRegister vRb, const Register k);
 898 
 899  public:
 900   void sha256(bool multi_block);
 901   void sha512(bool multi_block);
 902 
 903 
 904   //
 905   // Debugging
 906   //
 907 
 908   // assert on cr0
 909   void asm_assert(bool check_equal, const char* msg, int id);
 910   void asm_assert_eq(const char* msg, int id) { asm_assert(true, msg, id); }
 911   void asm_assert_ne(const char* msg, int id) { asm_assert(false, msg, id); }
 912 
 913  private:
 914   void asm_assert_mems_zero(bool check_equal, int size, int mem_offset, Register mem_base,
 915                             const char* msg, int id);
 916 
 917  public:
 918 
 919   void asm_assert_mem8_is_zero(int mem_offset, Register mem_base, const char* msg, int id) {
 920     asm_assert_mems_zero(true,  8, mem_offset, mem_base, msg, id);
 921   }
 922   void asm_assert_mem8_isnot_zero(int mem_offset, Register mem_base, const char* msg, int id) {
 923     asm_assert_mems_zero(false, 8, mem_offset, mem_base, msg, id);
 924   }
 925 
 926   // Verify R16_thread contents.
 927   void verify_thread();
 928 
 929   // Emit code to verify that reg contains a valid oop if +VerifyOops is set.
 930   void verify_oop(Register reg, const char* s = "broken oop");
 931   void verify_oop_addr(RegisterOrConstant offs, Register base, const char* s = "contains broken oop");
 932 
 933   // TODO: verify method and klass metadata (compare against vptr?)
 934   void _verify_method_ptr(Register reg, const char * msg, const char * file, int line) {}
 935   void _verify_klass_ptr(Register reg, const char * msg, const char * file, int line) {}
 936 
 937   // Convenience method returning function entry. For the ELFv1 case
 938   // creates function descriptor at the current address and returs
 939   // the pointer to it. For the ELFv2 case returns the current address.
 940   inline address function_entry();
 941 
 942 #define verify_method_ptr(reg) _verify_method_ptr(reg, "broken method " #reg, __FILE__, __LINE__)
 943 #define verify_klass_ptr(reg) _verify_klass_ptr(reg, "broken klass " #reg, __FILE__, __LINE__)
 944 
 945  private:
 946 
 947   enum {
 948     stop_stop                = 0,
 949     stop_untested            = 1,
 950     stop_unimplemented       = 2,
 951     stop_shouldnotreachhere  = 3,
 952     stop_end                 = 4
 953   };
 954   void stop(int type, const char* msg, int id);
 955 
 956  public:
 957   // Prints msg, dumps registers and stops execution.
 958   void stop         (const char* msg = "", int id = 0) { stop(stop_stop,               msg, id); }
 959   void untested     (const char* msg = "", int id = 0) { stop(stop_untested,           msg, id); }
 960   void unimplemented(const char* msg = "", int id = 0) { stop(stop_unimplemented,      msg, id); }
 961   void should_not_reach_here()                         { stop(stop_shouldnotreachhere,  "", -1); }
 962 
 963   void zap_from_to(Register low, int before, Register high, int after, Register val, Register addr) PRODUCT_RETURN;
 964 };
 965 
 966 // class SkipIfEqualZero:
 967 //
 968 // Instantiating this class will result in assembly code being output that will
 969 // jump around any code emitted between the creation of the instance and it's
 970 // automatic destruction at the end of a scope block, depending on the value of
 971 // the flag passed to the constructor, which will be checked at run-time.
 972 class SkipIfEqualZero : public StackObj {
 973  private:
 974   MacroAssembler* _masm;
 975   Label _label;
 976 
 977  public:
 978    // 'Temp' is a temp register that this object can use (and trash).
 979    explicit SkipIfEqualZero(MacroAssembler*, Register temp, const bool* flag_addr);
 980    static void skip_to_label_if_equal_zero(MacroAssembler*, Register temp,
 981                                            const bool* flag_addr, Label& label);
 982    ~SkipIfEqualZero();
 983 };
 984 
 985 #endif // CPU_PPC_VM_MACROASSEMBLER_PPC_HPP