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Diffstat (limited to 'examples/aarch64/check-bounds.cc')
-rw-r--r-- | examples/aarch64/check-bounds.cc | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/examples/aarch64/check-bounds.cc b/examples/aarch64/check-bounds.cc new file mode 100644 index 00000000..9d2bcbad --- /dev/null +++ b/examples/aarch64/check-bounds.cc @@ -0,0 +1,103 @@ +// Copyright 2014, VIXL authors +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are met: +// +// * Redistributions of source code must retain the above copyright notice, +// this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above copyright notice, +// this list of conditions and the following disclaimer in the documentation +// and/or other materials provided with the distribution. +// * Neither the name of ARM Limited nor the names of its contributors may be +// used to endorse or promote products derived from this software without +// specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND +// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE +// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +#include "examples.h" + +#define __ masm-> + +void GenerateCheckBounds(MacroAssembler* masm) { + // uint64_t check_bounds(uint64_t value, uint64_t low, uint64_t high) + // Argument locations: + // value -> x0 + // low -> x1 + // high -> x2 + + // First we compare 'value' with the 'low' bound. If x1 <= x0 the N flag will + // be cleared. This configuration can be checked with the 'pl' condition. + __ Cmp(x0, x1); + + // Now we will compare 'value' and 'high' (x0 and x2) but only if the 'pl' + // condition is verified. If the condition is not verified, we will clear + // all the flags except the carry one (C flag). + __ Ccmp(x0, x2, CFlag, pl); + + // We set x0 to 1 only if the 'ls' condition is satisfied. + // 'ls' performs the following test: !(C==1 && Z==0). If the previous + // comparison has been skipped we have C==1 and Z==0, so the 'ls' test + // will fail and x0 will be set to 0. + // Otherwise if the previous comparison occurred, x0 will be set to 1 + // only if x0 is less than or equal to x2. + __ Cset(x0, ls); + + __ Ret(); +} + + +#ifndef TEST_EXAMPLES +#ifdef VIXL_INCLUDE_SIMULATOR +void run_function(Simulator* simulator, + Instruction* function, + uint64_t value, + uint64_t low, + uint64_t high) { + simulator->WriteXRegister(0, value); + simulator->WriteXRegister(1, low); + simulator->WriteXRegister(2, high); + + simulator->RunFrom(function); + printf("%" PRIu64 " %s between %" PRIu64 " and %" PRIu64 "\n", + value, + simulator->ReadXRegister(0) ? "is" : "is not", + low, + high); + + simulator->ResetState(); +} + +int main(void) { + MacroAssembler masm; + Decoder decoder; + Simulator simulator(&decoder); + + // Generate the code for the example function. + Label check_bounds; + masm.Bind(&check_bounds); + GenerateCheckBounds(&masm); + masm.FinalizeCode(); + + // Run the example function. + Instruction* function = masm.GetLabelAddress<Instruction*>(&check_bounds); + run_function(&simulator, function, 546, 50, 1000); + run_function(&simulator, function, 62, 100, 200); + run_function(&simulator, function, 200, 100, 200); + + return 0; +} +#else +// Without the simulator there is nothing to test. +int main(void) { return 0; } +#endif // VIXL_INCLUDE_SIMULATOR +#endif // TEST_EXAMPLES |