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      1 // Copyright 2014, ARM Limited
      2 // All rights reserved.
      3 //
      4 // Redistribution and use in source and binary forms, with or without
      5 // modification, are permitted provided that the following conditions are met:
      6 //
      7 //   * Redistributions of source code must retain the above copyright notice,
      8 //     this list of conditions and the following disclaimer.
      9 //   * Redistributions in binary form must reproduce the above copyright notice,
     10 //     this list of conditions and the following disclaimer in the documentation
     11 //     and/or other materials provided with the distribution.
     12 //   * Neither the name of ARM Limited nor the names of its contributors may be
     13 //     used to endorse or promote products derived from this software without
     14 //     specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
     17 // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     18 // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     19 // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
     20 // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21 // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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     23 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     25 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26 
     27 #include "examples.h"
     28 #include "non-const-visitor.h"
     29 
     30 #define BUF_SIZE (4096)
     31 #define __ masm->
     32 
     33 
     34 void GenerateNonConstVisitorTestCode(MacroAssembler* masm) {
     35   // int64_t foo(int64_t a, int64_t b)
     36   //  Argument locations:
     37   //    a -> x0
     38   //    b -> x1
     39   __ Sub(x0, x0, x1);
     40   // The return value is in x0.
     41   __ Ret();
     42 }
     43 
     44 
     45 int64_t RunNonConstVisitorTestGeneratedCode(const Instruction* start_instr) {
     46 #ifdef VIXL_INCLUDE_SIMULATOR
     47   Decoder simulator_decoder;
     48   Simulator simulator(&simulator_decoder);
     49 
     50   int64_t a = 5;
     51   int64_t b = 2;
     52   simulator.set_xreg(0, a);
     53   simulator.set_xreg(1, b);
     54   simulator.RunFrom(start_instr);
     55   int64_t res = simulator.xreg(0);
     56   printf("foo(%" PRId64", %" PRId64") = %" PRId64"\n", a, b, res);
     57 
     58   return res;
     59 #else
     60   // Without the simulator there is nothing to test.
     61   USE(start_instr);
     62   return 0;
     63 #endif
     64 }
     65 
     66 
     67 #ifndef TEST_EXAMPLES
     68 #ifdef VIXL_INCLUDE_SIMULATOR
     69 int main(void) {
     70   // Create and initialize the assembler.
     71   byte assm_buf[BUF_SIZE];
     72   MacroAssembler masm(assm_buf, BUF_SIZE);
     73 
     74   // Generate the code.
     75   Label code_start, code_end;
     76   masm.Bind(&code_start);
     77   GenerateNonConstVisitorTestCode(&masm);
     78   masm.Bind(&code_end);
     79   masm.FinalizeCode();
     80   Instruction* instr_start = masm.GetLabelAddress<Instruction*>(&code_start);
     81   Instruction* instr_end = masm.GetLabelAddress<Instruction*>(&code_end);
     82 
     83   // Run the code a first time.
     84   RunNonConstVisitorTestGeneratedCode(instr_start);
     85 
     86   // Instantiate a decoder, disassembler, and our custom modifying visitor.
     87   Decoder decoder;
     88   PrintDisassembler disasm(stdout);
     89   SwitchAddSubRegisterSources modifying_visitor;
     90 
     91   // Register visitors in such a way that when visiting instructions, the
     92   // decoder will first disassemble the original instruction, modify it, and
     93   // then disassemble the modified instruction.
     94   decoder.AppendVisitor(&disasm);
     95   decoder.AppendVisitor(&modifying_visitor);
     96   decoder.AppendVisitor(&disasm);
     97 
     98   // Iterate through the instructions.
     99   Instruction* instr;
    100   for (instr = instr_start; instr < instr_end; instr += kInstructionSize) {
    101     printf("---\n");
    102     decoder.Decode(instr);
    103   }
    104 
    105   // Run the modified code and observe the different output from before.
    106   RunNonConstVisitorTestGeneratedCode(instr_start);
    107 
    108   return 0;
    109 }
    110 #else
    111 // Without the simulator there is nothing to test.
    112 int main(void) { return 0; }
    113 #endif  // VIXL_INCLUDE_SIMULATOR
    114 #endif  // TEST_EXAMPLES
    115 
    116 
    117 // This is only used by the testing code.
    118 void ModifyNonConstVisitorTestGeneratedCode(Instruction* start,
    119                                             Instruction* end) {
    120   Decoder decoder;
    121   SwitchAddSubRegisterSources modifying_visitor;
    122   decoder.AppendVisitor(&modifying_visitor);
    123 
    124   Instruction* instr;
    125   for (instr = start; instr < end; instr += kInstructionSize) {
    126     printf("---\n");
    127     decoder.Decode(instr);
    128   }
    129 }
    130