examples/abs.cc

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#include "examples.h"

#define BUF_SIZE (4096)
#define __ masm->

void GenerateAbs(MacroAssembler* masm) {
  // int64_t abs(int64_t x)
  // Argument location:
  //   x -> x0

  // This example uses a conditional instruction (cneg) to compute the
  // absolute value of an integer.
  __ Cmp(x0, 0);
  __ Cneg(x0, x0, mi);
  __ Ret();
}


#ifndef TEST_EXAMPLES
#ifdef VIXL_INCLUDE_SIMULATOR
int main(void) {
  // Create and initialize the assembler and the simulator.
  byte assm_buf[BUF_SIZE];
  MacroAssembler masm(assm_buf, BUF_SIZE);
  Decoder decoder;
  Simulator simulator(&decoder);

  // Generate the code for the example function.
  Label abs;
  masm.Bind(&abs);
  GenerateAbs(&masm);
  masm.FinalizeCode();

  // Run the example function.
  int64_t input_value = -42;
  simulator.set_xreg(0, input_value);
  simulator.RunFrom(masm.GetLabelAddress<Instruction*>(&abs));
  printf("abs(%" PRId64 ") = %" PRId64 "\n", input_value, simulator.xreg(0));

  return 0;
}
#else
// Without the simulator there is nothing to test.
int main(void) { return 0; }
#endif  // VIXL_INCLUDE_SIMULATOR
#endif  // TEST_EXAMPLES