1 // Copyright 2014, VIXL authors 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 22 // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 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 29 #define __ masm-> 30 31 void GenerateSwapInt32(MacroAssembler* masm) { 32 { 33 // In this scope the register x2 will be used by the macro-assembler 34 // as the stack pointer (via peek, poke, push, etc). 35 const Register old_stack_pointer = __ StackPointer(); 36 __ Mov(x2, __ StackPointer()); 37 __ SetStackPointer(x2); 38 39 // This call to Claim is not 16-byte aligned and would have failed 40 // if the current stack pointer was sp. 41 __ Claim(8); 42 43 __ Poke(w0, 0); 44 __ Poke(w1, 4); 45 __ Peek(w1, 0); 46 __ Peek(w0, 4); 47 48 __ Drop(8); 49 50 // Even if we didn't use the system stack pointer, sp might have been 51 // modified because the ABI forbids access to memory below the stack 52 // pointer. 53 __ Mov(old_stack_pointer, __ StackPointer()); 54 __ SetStackPointer(old_stack_pointer); 55 } 56 57 // The stack pointer has now been switched back to sp. 58 __ Ret(); 59 } 60 61 62 #ifndef TEST_EXAMPLES 63 #ifdef VIXL_INCLUDE_SIMULATOR_AARCH64 64 int main(void) { 65 MacroAssembler masm; 66 Decoder decoder; 67 Simulator simulator(&decoder); 68 69 // Generate the code for the example function. 70 Label swap_int32; 71 masm.Bind(&swap_int32); 72 GenerateSwapInt32(&masm); 73 masm.FinalizeCode(); 74 75 // Run the example function. 76 simulator.WriteWRegister(0, 0x11111111); 77 simulator.WriteWRegister(1, 0x22222222); 78 79 // clang-format off 80 printf("Before swap_int32:\n" 81 "x0 = 0x%" PRIx32 "\n" 82 "x1 = 0x%" PRIx32 "\n", 83 simulator.ReadWRegister(0), simulator.ReadWRegister(1)); 84 // clang-format on 85 86 simulator.RunFrom(masm.GetLabelAddress<Instruction*>(&swap_int32)); 87 88 // clang-format off 89 printf("After swap_int32:\n" 90 "x0 = 0x%" PRIx32 "\n" 91 "x1 = 0x%" PRIx32 "\n", 92 simulator.ReadWRegister(0), simulator.ReadWRegister(1)); 93 // clang-format on 94 95 return 0; 96 } 97 #else 98 // Without the simulator there is nothing to test. 99 int main(void) { return 0; } 100 #endif // VIXL_INCLUDE_SIMULATOR_AARCH64 101 #endif // TEST_EXAMPLES 102
