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 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 BUF_SIZE (4096) 30 #define __ masm-> 31 32 void GenerateSwapInt32(MacroAssembler* masm) { 33 { 34 // In this scope the register x2 will be used by the macro-assembler 35 // as the stack pointer (via peek, poke, push, etc). 36 const Register old_stack_pointer = __ StackPointer(); 37 __ Mov(x2, __ StackPointer()); 38 __ SetStackPointer(x2); 39 40 // This call to Claim is not 16-byte aligned and would have failed 41 // if the current stack pointer was sp. 42 __ Claim(8); 43 44 __ Poke(w0, 0); 45 __ Poke(w1, 4); 46 __ Peek(w1, 0); 47 __ Peek(w0, 4); 48 49 __ Drop(8); 50 51 // Even if we didn't use the system stack pointer, sp might have been 52 // modified because the ABI forbids access to memory below the stack 53 // pointer. 54 __ Mov(old_stack_pointer, __ StackPointer()); 55 __ SetStackPointer(old_stack_pointer); 56 } 57 58 // The stack pointer has now been switched back to sp. 59 __ Ret(); 60 } 61 62 63 #ifndef TEST_EXAMPLES 64 #ifdef VIXL_INCLUDE_SIMULATOR 65 int main(void) { 66 // Create and initialize the assembler and the simulator. 67 byte assm_buf[BUF_SIZE]; 68 MacroAssembler masm(assm_buf, BUF_SIZE); 69 Decoder decoder; 70 Simulator simulator(&decoder); 71 72 // Generate the code for the example function. 73 Label swap_int32; 74 masm.Bind(&swap_int32); 75 GenerateSwapInt32(&masm); 76 masm.FinalizeCode(); 77 78 // Run the example function. 79 simulator.set_wreg(0, 0x11111111); 80 simulator.set_wreg(1, 0x22222222); 81 82 printf("Before swap_int32:\n" 83 "x0 = 0x%" PRIx32 "\n" 84 "x1 = 0x%" PRIx32 "\n", 85 simulator.wreg(0), simulator.wreg(1)); 86 87 simulator.RunFrom(masm.GetLabelAddress<Instruction*>(&swap_int32)); 88 89 printf("After swap_int32:\n" 90 "x0 = 0x%" PRIx32 "\n" 91 "x1 = 0x%" PRIx32 "\n", 92 simulator.wreg(0), simulator.wreg(1)); 93 94 return 0; 95 } 96 #else 97 // Without the simulator there is nothing to test. 98 int main(void) { return 0; } 99 #endif // VIXL_INCLUDE_SIMULATOR 100 #endif // TEST_EXAMPLES 101
