1 // Copyright 2015, 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 GenerateCrc32(MacroAssembler* masm) { 33 // uint32_t crc32(const char *msg, size_t length) 34 // Argument location: 35 // msg (pointer) -> x0 36 // length (integer) -> x1 37 38 // This example computes CRC32CB on an input array of a given size 39 // and returns the resulting checksum in w0. 40 41 Label loop, end; 42 43 // Move input array to temp register so we can re-use w0 as return register. 44 __ Mov(x2, x0); 45 46 // Initial remainder for the checksum. If length=0, then this value will 47 // be returned. 48 __ Mov(w0, 0xffffffff); 49 50 // Loop for iterating through the array, starting at msg[0]. 51 __ Bind(&loop); 52 53 // If no more elements to process, then exit function. 54 __ Cbz(x1, &end); 55 __ Sub(x1, x1, 1); 56 57 // Compute checksum for msg[i]. 58 __ Ldrb(w3, MemOperand(x2, 1, PostIndex)); 59 __ Crc32b(w0, w0, w3); 60 __ B(&loop); 61 62 __ Bind(&end); 63 64 __ Ret(); 65 } 66 67 #ifndef TEST_EXAMPLES 68 69 void runExample(const char *msg) { 70 // Create and initialize the assembler and the simulator. 71 byte assm_buf[BUF_SIZE]; 72 MacroAssembler masm(assm_buf, BUF_SIZE); 73 74 // Generate the code for the example function. 75 Label func; 76 masm.Bind(&func); 77 GenerateCrc32(&masm); 78 masm.FinalizeCode(); 79 80 #ifdef VIXL_INCLUDE_SIMULATOR 81 // Run example function in the simulator. 82 uintptr_t msg_addr = reinterpret_cast<uintptr_t>(msg); 83 size_t msg_size = strlen(msg); 84 Decoder decoder; 85 Simulator simulator(&decoder); 86 simulator.set_xreg(0, msg_addr); 87 simulator.set_xreg(1, msg_size); 88 simulator.RunFrom(masm.GetLabelAddress<Instruction*>(&func)); 89 printf("crc32(\"%s\")=0x%x\n", msg, simulator.wreg(0)); 90 #else 91 // Run example function natively. 92 printf("Not yet implemented.\n"); 93 USE(msg); 94 #endif // VIXL_INCLUDE_SIMULATOR 95 } 96 97 98 int main(void) { 99 runExample("Hello World!"); 100 runExample("do"); 101 runExample("1"); 102 runExample(""); 103 104 return 0; 105 } 106 #endif // TEST_EXAMPLES 107
