Package ghidra.pcode.emu.jit.gen.op

Enum Class LzCountOpGen

java.lang.Object
java.lang.Enum<LzCountOpGen>
ghidra.pcode.emu.jit.gen.op.LzCountOpGen
All Implemented Interfaces:
IntCountUnOpGen<JitLzCountOp>, OpGen<JitLzCountOp>, UnOpGen<JitLzCountOp>, Serializable, Comparable<LzCountOpGen>, Constable
public enum LzCountOpGen extends Enum<LzCountOpGen> implements IntCountUnOpGen<JitLzCountOp>
The generator for a lzcount.

This uses the unary operator generator and emits an invocation of Integer.numberOfLeadingZeros(int) or Long.numberOfLeadingZeros(long), depending on the type.

  • Enum Constant Details

    • GEN

      public static final LzCountOpGen GEN
      The generator singleton

  • Method Details

    • values

      public static LzCountOpGen[] values()
      Returns an array containing the constants of this enum class, in the order they are declared.
      Returns:
      an array containing the constants of this enum class, in the order they are declared

    • valueOf

      public static LzCountOpGen valueOf(String name)
      Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)
      Parameters:
      name - the name of the enum constant to be returned.
      Returns:
      the enum constant with the specified name
      Throws:
      IllegalArgumentException - if this enum class has no constant with the specified name
      NullPointerException - if the argument is null

    • isSigned

      public boolean isSigned()
      Description copied from interface: UnOpGen
      Whether this operator is signed

      In many cases, the operator itself is not affected by the signedness of the operands; however, if size adjustments to the operands are needed, this can determine how those operands are extended.

      Specified by:
      isSigned in interface UnOpGen<JitLzCountOp>
      Returns:
      true for signed, false if not

    • opForInt

      public <N1 extends Emitter.Next, N0 extends Emitter.Ent<N1, Types.TInt>> Emitter<Emitter.Ent<N1,Types.TInt>> opForInt(Emitter<N0> em, JitType.IntJitType type)
      Description copied from interface: IntCountUnOpGen
      Emit the JVM bytecode to perform the operator with int operands on the stack.
      Specified by:
      opForInt in interface IntCountUnOpGen<JitLzCountOp>
      Type Parameters:
      N1 - the tail of the incoming stack
      N0 - the incoming stack with the input operand on top
      Parameters:
      em - the emitter typed with the incoming stack
      type - the p-code type of the input operand
      Returns:
      the emitter typed with the resulting stack, i.e., the tail with the result pushed

    • opForLong

      public <N1 extends Emitter.Next, N0 extends Emitter.Ent<N1, Types.TLong>> Emitter<Emitter.Ent<N1,Types.TInt>> opForLong(Emitter<N0> em, JitType.LongJitType type)
      Description copied from interface: IntCountUnOpGen
      Emit the JVM bytecode to perform the operator with long operands on the stack.
      Specified by:
      opForLong in interface IntCountUnOpGen<JitLzCountOp>
      Type Parameters:
      N1 - the tail of the incoming stack
      N0 - the incoming stack with the input operand on top
      Parameters:
      em - the emitter typed with the incoming stack
      type - the p-code type of the input operand
      Returns:
      the emitter typed with the resulting stack, i.e., the tail with the result pushed

    • genRunMpInt

      public <THIS extends JitCompiledPassage> Emitter<Emitter.Ent<Emitter.Bot,Types.TInt>> genRunMpInt(Emitter<Emitter.Bot> em, Local<Types.TRef<THIS>> localThis, JitCodeGenerator<THIS> gen, JitLzCountOp op, JitType.MpIntJitType type, Scope scope)
      Emit the JVM bytecode to perform the operator with mp-int operands.

      The strategy here is straightforward: Start with the most-significant leg, totalling up the number of leading zeros, until we encounter a situation where the leg did not have 32 zeros. We test for this by checking if the running total is equal to 32 times the number of legs processed so far. We need not load or compute any legs beyond the point where we come up with less. When we reach the end, we made need to subtract some constant number of bits to account for types that do not occupy the full most-significant leg.

      Specified by:
      genRunMpInt in interface IntCountUnOpGen<JitLzCountOp>
      Type Parameters:
      THIS - the type of the generated passage
      Parameters:
      em - the emitter typed with the empty stack
      localThis - a handle to the local holding the this reference
      gen - the code generator
      op - the p-code op
      type - the p-code type of the input operand
      scope - a scope for generating temporary local storage
      Returns:
      the emitter typed with the resulting stack, i.e., with only the result pushed