OpCodes Class

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Provides field representations of the Microsoft intermediate language (MSIL) instructions for emission by the ILGenerator class members (such as Emit).

Inheritance Hierarchy

System..::.Object
System.Reflection.Emit..::.OpCodes

Namespace: System.Reflection.Emit
Assembly: mscorlib (in mscorlib.dll)

Syntax

Public Class OpCodes
public class OpCodes

The OpCodes type exposes the following members.

Methods

Name Description
Equals(Object) Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Finalize Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
GetHashCode Serves as a hash function for a particular type. (Inherited from Object.)
GetType Gets the Type of the current instance. (Inherited from Object.)
MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
TakesSingleByteArgument Returns true or false if the supplied opcode takes a single byte argument.
ToString Returns a string that represents the current object. (Inherited from Object.)

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Fields

Name Description
Add Adds two values and pushes the result onto the evaluation stack.
Add_Ovf Adds two integers, performs an overflow check, and pushes the result onto the evaluation stack.
Add_Ovf_Un Adds two unsigned integer values, performs an overflow check, and pushes the result onto the evaluation stack.
And Computes the bitwise AND of two values and pushes the result onto the evaluation stack.
Arglist Returns an unmanaged pointer to the argument list of the current method.
Beq Transfers control to a target instruction if two values are equal.
Beq_S Transfers control to a target instruction (short form) if two values are equal.
Bge Transfers control to a target instruction if the first value is greater than or equal to the second value.
Bge_S Transfers control to a target instruction (short form) if the first value is greater than or equal to the second value.
Bge_Un Transfers control to a target instruction if the first value is greater than the second value, when comparing unsigned integer values or unordered float values.
Bge_Un_S Transfers control to a target instruction (short form) if the first value is greater than the second value, when comparing unsigned integer values or unordered float values.
Bgt Transfers control to a target instruction if the first value is greater than the second value.
Bgt_S Transfers control to a target instruction (short form) if the first value is greater than the second value.
Bgt_Un Transfers control to a target instruction if the first value is greater than the second value, when comparing unsigned integer values or unordered float values.
Bgt_Un_S Transfers control to a target instruction (short form) if the first value is greater than the second value, when comparing unsigned integer values or unordered float values.
Ble Transfers control to a target instruction if the first value is less than or equal to the second value.
Ble_S Transfers control to a target instruction (short form) if the first value is less than or equal to the second value.
Ble_Un Transfers control to a target instruction if the first value is less than or equal to the second value, when comparing unsigned integer values or unordered float values.
Ble_Un_S Transfers control to a target instruction (short form) if the first value is less than or equal to the second value, when comparing unsigned integer values or unordered float values.
Blt Transfers control to a target instruction if the first value is less than the second value.
Blt_S Transfers control to a target instruction (short form) if the first value is less than the second value.
Blt_Un Transfers control to a target instruction if the first value is less than the second value, when comparing unsigned integer values or unordered float values.
Blt_Un_S Transfers control to a target instruction (short form) if the first value is less than the second value, when comparing unsigned integer values or unordered float values.
Bne_Un Transfers control to a target instruction when two unsigned integer values or unordered float values are not equal.
Bne_Un_S Transfers control to a target instruction (short form) when two unsigned integer values or unordered float values are not equal.
Box Converts a value type to an object reference (type O).
Br Unconditionally transfers control to a target instruction.
Br_S Unconditionally transfers control to a target instruction (short form).
Break Signals the Common Language Infrastructure (CLI) to inform the debugger that a break point has been tripped.
Brfalse Transfers control to a target instruction if value is false, a null reference (Nothing in Visual Basic), or zero.
Brfalse_S Transfers control to a target instruction if value is false, a null reference, or zero.
Brtrue Transfers control to a target instruction if value is true, not null, or non-zero.
Brtrue_S Transfers control to a target instruction (short form) if value is true, not null, or non-zero.
Call Calls the method indicated by the passed method descriptor.
Calli Calls the method indicated on the evaluation stack (as a pointer to an entry point) with arguments described by a calling convention.
Callvirt Calls a late-bound method on an object, pushing the return value onto the evaluation stack.
Castclass Attempts to cast an object passed by reference to the specified class.
Ceq Compares two values. If they are equal, the integer value 1 (int32) is pushed onto the evaluation stack; otherwise 0 (int32) is pushed onto the evaluation stack.
Cgt Compares two values. If the first value is greater than the second, the integer value 1 (int32) is pushed onto the evaluation stack; otherwise 0 (int32) is pushed onto the evaluation stack.
Cgt_Un Compares two unsigned or unordered values. If the first value is greater than the second, the integer value 1 (int32) is pushed onto the evaluation stack; otherwise 0 (int32) is pushed onto the evaluation stack.
Ckfinite Throws ArithmeticException if value is not a finite number.
Clt Compares two values. If the first value is less than the second, the integer value 1 (int32) is pushed onto the evaluation stack; otherwise 0 (int32) is pushed onto the evaluation stack.
Clt_Un Compares the unsigned or unordered values value1 and value2. If value1 is less than value2, then the integer value 1 (int32) is pushed onto the evaluation stack; otherwise 0 (int32) is pushed onto the evaluation stack.
Constrained Constrains the type on which a virtual method call is made.
Conv_I Converts the value on top of the evaluation stack to native int.
Conv_I1 Converts the value on top of the evaluation stack to int8, then extends (pads) it to int32.
Conv_I2 Converts the value on top of the evaluation stack to int16, then extends (pads) it to int32.
Conv_I4 Converts the value on top of the evaluation stack to int32.
Conv_I8 Converts the value on top of the evaluation stack to int64.
Conv_Ovf_I Converts the signed value on top of the evaluation stack to signed native int, throwing OverflowException on overflow.
Conv_Ovf_I_Un Converts the unsigned value on top of the evaluation stack to signed native int, throwing OverflowException on overflow.
Conv_Ovf_I1 Converts the signed value on top of the evaluation stack to signed int8 and extends it to int32, throwing OverflowException on overflow.
Conv_Ovf_I1_Un Converts the unsigned value on top of the evaluation stack to signed int8 and extends it to int32, throwing OverflowException on overflow.
Conv_Ovf_I2 Converts the signed value on top of the evaluation stack to signed int16 and extending it to int32, throwing OverflowException on overflow.
Conv_Ovf_I2_Un Converts the unsigned value on top of the evaluation stack to signed int16 and extends it to int32, throwing OverflowException on overflow.
Conv_Ovf_I4 Converts the signed value on top of the evaluation stack to signed int32, throwing OverflowException on overflow.
Conv_Ovf_I4_Un Converts the unsigned value on top of the evaluation stack to signed int32, throwing OverflowException on overflow.
Conv_Ovf_I8 Converts the signed value on top of the evaluation stack to signed int64, throwing OverflowException on overflow.
Conv_Ovf_I8_Un Converts the unsigned value on top of the evaluation stack to signed int64, throwing OverflowException on overflow.
Conv_Ovf_U Converts the signed value on top of the evaluation stack to unsigned native int, throwing OverflowException on overflow.
Conv_Ovf_U_Un Converts the unsigned value on top of the evaluation stack to unsigned native int, throwing OverflowException on overflow.
Conv_Ovf_U1 Converts the signed value on top of the evaluation stack to unsigned int8 and extends it to int32, throwing OverflowException on overflow.
Conv_Ovf_U1_Un Converts the unsigned value on top of the evaluation stack to unsigned int8 and extends it to int32, throwing OverflowException on overflow.
Conv_Ovf_U2 Converts the signed value on top of the evaluation stack to unsigned int16 and extends it to int32, throwing OverflowException on overflow.
Conv_Ovf_U2_Un Converts the unsigned value on top of the evaluation stack to unsigned int16 and extends it to int32, throwing OverflowException on overflow.
Conv_Ovf_U4 Converts the signed value on top of the evaluation stack to unsigned int32, throwing OverflowException on overflow.
Conv_Ovf_U4_Un Converts the unsigned value on top of the evaluation stack to unsigned int32, throwing OverflowException on overflow.
Conv_Ovf_U8 Converts the signed value on top of the evaluation stack to unsigned int64, throwing OverflowException on overflow.
Conv_Ovf_U8_Un Converts the unsigned value on top of the evaluation stack to unsigned int64, throwing OverflowException on overflow.
Conv_R_Un Converts the unsigned integer value on top of the evaluation stack to float32.
Conv_R4 Converts the value on top of the evaluation stack to float32.
Conv_R8 Converts the value on top of the evaluation stack to float64.
Conv_U Converts the value on top of the evaluation stack to unsigned native int, and extends it to native int.
Conv_U1 Converts the value on top of the evaluation stack to unsigned int8, and extends it to int32.
Conv_U2 Converts the value on top of the evaluation stack to unsigned int16, and extends it to int32.
Conv_U4 Converts the value on top of the evaluation stack to unsigned int32, and extends it to int32.
Conv_U8 Converts the value on top of the evaluation stack to unsigned int64, and extends it to int64.
Cpblk Copies a specified number bytes from a source address to a destination address.
Cpobj Copies the value type located at the address of an object (type &, * or native int) to the address of the destination object (type &, * or native int).
Div Divides two values and pushes the result as a floating-point (type F) or quotient (type int32) onto the evaluation stack.
Div_Un Divides two unsigned integer values and pushes the result (int32) onto the evaluation stack.
Dup Copies the current topmost value on the evaluation stack, and then pushes the copy onto the evaluation stack.
Endfilter Transfers control from the filter clause of an exception back to the Common Language Infrastructure (CLI) exception handler.
Endfinally Transfers control from the fault or finally clause of an exception block back to the Common Language Infrastructure (CLI) exception handler.
Initblk Initializes a specified block of memory at a specific address to a given size and initial value.
Initobj Initializes each field of the value type at a specified address to a null reference or a 0 of the appropriate primitive type.
Isinst Tests whether an object reference (type O) is an instance of a particular class.
Jmp Exits current method and jumps to specified method.
Ldarg Loads an argument (referenced by a specified index value) onto the stack.
Ldarg_0 Loads the argument at index 0 onto the evaluation stack.
Ldarg_1 Loads the argument at index 1 onto the evaluation stack.
Ldarg_2 Loads the argument at index 2 onto the evaluation stack.
Ldarg_3 Loads the argument at index 3 onto the evaluation stack.
Ldarg_S Loads the argument (referenced by a specified short form index) onto the evaluation stack.
Ldarga Load an argument address onto the evaluation stack.
Ldarga_S Load an argument address, in short form, onto the evaluation stack.
Ldc_I4 Pushes a supplied value of type int32 onto the evaluation stack as an int32.
Ldc_I4_0 Pushes the integer value of 0 onto the evaluation stack as an int32.
Ldc_I4_1 Pushes the integer value of 1 onto the evaluation stack as an int32.
Ldc_I4_2 Pushes the integer value of 2 onto the evaluation stack as an int32.
Ldc_I4_3 Pushes the integer value of 3 onto the evaluation stack as an int32.
Ldc_I4_4 Pushes the integer value of 4 onto the evaluation stack as an int32.
Ldc_I4_5 Pushes the integer value of 5 onto the evaluation stack as an int32.
Ldc_I4_6 Pushes the integer value of 6 onto the evaluation stack as an int32.
Ldc_I4_7 Pushes the integer value of 7 onto the evaluation stack as an int32.
Ldc_I4_8 Pushes the integer value of 8 onto the evaluation stack as an int32.
Ldc_I4_M1 Pushes the integer value of -1 onto the evaluation stack as an int32.
Ldc_I4_S Pushes the supplied int8 value onto the evaluation stack as an int32, short form.
Ldc_I8 Pushes a supplied value of type int64 onto the evaluation stack as an int64.
Ldc_R4 Pushes a supplied value of type float32 onto the evaluation stack as type F (float).
Ldc_R8 Pushes a supplied value of type float64 onto the evaluation stack as type F (float).
Ldelem Loads the element at a specified array index onto the top of the evaluation stack as the type specified in the instruction.
Ldelem_I Loads the element with type native int at a specified array index onto the top of the evaluation stack as a native int.
Ldelem_I1 Loads the element with type int8 at a specified array index onto the top of the evaluation stack as an int32.
Ldelem_I2 Loads the element with type int16 at a specified array index onto the top of the evaluation stack as an int32.
Ldelem_I4 Loads the element with type int32 at a specified array index onto the top of the evaluation stack as an int32.
Ldelem_I8 Loads the element with type int64 at a specified array index onto the top of the evaluation stack as an int64.
Ldelem_R4 Loads the element with type float32 at a specified array index onto the top of the evaluation stack as type F (float).
Ldelem_R8 Loads the element with type float64 at a specified array index onto the top of the evaluation stack as type F (float).
Ldelem_Ref Loads the element containing an object reference at a specified array index onto the top of the evaluation stack as type O (object reference).
Ldelem_U1 Loads the element with type unsigned int8 at a specified array index onto the top of the evaluation stack as an int32.
Ldelem_U2 Loads the element with type unsigned int16 at a specified array index onto the top of the evaluation stack as an int32.
Ldelem_U4 Loads the element with type unsigned int32 at a specified array index onto the top of the evaluation stack as an int32.
Ldelema Loads the address of the array element at a specified array index onto the top of the evaluation stack as type & (managed pointer).
Ldfld Finds the value of a field in the object whose reference is currently on the evaluation stack.
Ldflda Finds the address of a field in the object whose reference is currently on the evaluation stack.
Ldftn Pushes an unmanaged pointer (type native int) to the native code implementing a specific method onto the evaluation stack.
Ldind_I Loads a value of type native int as a native int onto the evaluation stack indirectly.
Ldind_I1 Loads a value of type int8 as an int32 onto the evaluation stack indirectly.
Ldind_I2 Loads a value of type int16 as an int32 onto the evaluation stack indirectly.
Ldind_I4 Loads a value of type int32 as an int32 onto the evaluation stack indirectly.
Ldind_I8 Loads a value of type int64 as an int64 onto the evaluation stack indirectly.
Ldind_R4 Loads a value of type float32 as a type F (float) onto the evaluation stack indirectly.
Ldind_R8 Loads a value of type float64 as a type F (float) onto the evaluation stack indirectly.
Ldind_Ref Loads an object reference as a type O (object reference) onto the evaluation stack indirectly.
Ldind_U1 Loads a value of type unsigned int8 as an int32 onto the evaluation stack indirectly.
Ldind_U2 Loads a value of type unsigned int16 as an int32 onto the evaluation stack indirectly.
Ldind_U4 Loads a value of type unsigned int32 as an int32 onto the evaluation stack indirectly.
Ldlen Pushes the number of elements of a zero-based, one-dimensional array onto the evaluation stack.
Ldloc Loads the local variable at a specific index onto the evaluation stack.
Ldloc_0 Loads the local variable at index 0 onto the evaluation stack.
Ldloc_1 Loads the local variable at index 1 onto the evaluation stack.
Ldloc_2 Loads the local variable at index 2 onto the evaluation stack.
Ldloc_3 Loads the local variable at index 3 onto the evaluation stack.
Ldloc_S Loads the local variable at a specific index onto the evaluation stack, short form.
Ldloca Loads the address of the local variable at a specific index onto the evaluation stack.
Ldloca_S Loads the address of the local variable at a specific index onto the evaluation stack, short form.
Ldnull Pushes a null reference (type O) onto the evaluation stack.
Ldobj Copies the value type object pointed to by an address to the top of the evaluation stack.
Ldsfld Pushes the value of a static field onto the evaluation stack.
Ldsflda Pushes the address of a static field onto the evaluation stack.
Ldstr Pushes a new object reference to a string literal stored in the metadata.
Ldtoken Converts a metadata token to its runtime representation, pushing it onto the evaluation stack.
Ldvirtftn Pushes an unmanaged pointer (type native int) to the native code implementing a particular virtual method associated with a specified object onto the evaluation stack.
Leave Exits a protected region of code, unconditionally transferring control to a specific target instruction.
Leave_S Exits a protected region of code, unconditionally transferring control to a target instruction (short form).
Localloc Allocates a certain number of bytes from the local dynamic memory pool and pushes the address (a transient pointer, type *) of the first allocated byte onto the evaluation stack.
Mkrefany Pushes a typed reference to an instance of a specific type onto the evaluation stack.
Mul Multiplies two values and pushes the result on the evaluation stack.
Mul_Ovf Multiplies two integer values, performs an overflow check, and pushes the result onto the evaluation stack.
Mul_Ovf_Un Multiplies two unsigned integer values, performs an overflow check, and pushes the result onto the evaluation stack.
Neg Negates a value and pushes the result onto the evaluation stack.
Newarr Pushes an object reference to a new zero-based, one-dimensional array whose elements are of a specific type onto the evaluation stack.
Newobj Creates a new object or a new instance of a value type, pushing an object reference (type O) onto the evaluation stack.
Nop Fills space if opcodes are patched. No meaningful operation is performed although a processing cycle can be consumed.
Not Computes the bitwise complement of the integer value on top of the stack and pushes the result onto the evaluation stack as the same type.
Or Compute the bitwise complement of the two integer values on top of the stack and pushes the result onto the evaluation stack.
Pop Removes the value currently on top of the evaluation stack.
Prefix1 Infrastructure. This is a reserved instruction.
Prefix2 Infrastructure. This is a reserved instruction.
Prefix3 Infrastructure. This is a reserved instruction.
Prefix4 Infrastructure. This is a reserved instruction.
Prefix5 Infrastructure. This is a reserved instruction.
Prefix6 Infrastructure. This is a reserved instruction.
Prefix7 Infrastructure. This is a reserved instruction.
Prefixref Infrastructure. This is a reserved instruction.
Readonly Specifies that the subsequent array address operation performs no type check at run time, and that it returns a managed pointer whose mutability is restricted.
Refanytype Retrieves the type token embedded in a typed reference.
Refanyval Retrieves the address (type &) embedded in a typed reference.
Rem Divides two values and pushes the remainder onto the evaluation stack.
Rem_Un Divides two unsigned values and pushes the remainder onto the evaluation stack.
Ret Returns from the current method, pushing a return value (if present) from the callee's evaluation stack onto the caller's evaluation stack.
Rethrow Rethrows the current exception.
Shl Shifts an integer value to the left (in zeroes) by a specified number of bits, pushing the result onto the evaluation stack.
Shr Shifts an integer value (in sign) to the right by a specified number of bits, pushing the result onto the evaluation stack.
Shr_Un Shifts an unsigned integer value (in zeroes) to the right by a specified number of bits, pushing the result onto the evaluation stack.
Sizeof Pushes the size, in bytes, of a supplied value type onto the evaluation stack.
Starg Stores the value on top of the evaluation stack in the argument slot at a specified index.
Starg_S Stores the value on top of the evaluation stack in the argument slot at a specified index, short form.
Stelem Replaces the array element at a given index with the value on the evaluation stack, whose type is specified in the instruction.
Stelem_I Replaces the array element at a given index with the native int value on the evaluation stack.
Stelem_I1 Replaces the array element at a given index with the int8 value on the evaluation stack.
Stelem_I2 Replaces the array element at a given index with the int16 value on the evaluation stack.
Stelem_I4 Replaces the array element at a given index with the int32 value on the evaluation stack.
Stelem_I8 Replaces the array element at a given index with the int64 value on the evaluation stack.
Stelem_R4 Replaces the array element at a given index with the float32 value on the evaluation stack.
Stelem_R8 Replaces the array element at a given index with the float64 value on the evaluation stack.
Stelem_Ref Replaces the array element at a given index with the object ref value (type O) on the evaluation stack.
Stfld Replaces the value stored in the field of an object reference or pointer with a new value.
Stind_I Stores a value of type native int at a supplied address.
Stind_I1 Stores a value of type int8 at a supplied address.
Stind_I2 Stores a value of type int16 at a supplied address.
Stind_I4 Stores a value of type int32 at a supplied address.
Stind_I8 Stores a value of type int64 at a supplied address.
Stind_R4 Stores a value of type float32 at a supplied address.
Stind_R8 Stores a value of type float64 at a supplied address.
Stind_Ref Stores a object reference value at a supplied address.
Stloc Pops the current value from the top of the evaluation stack and stores it in a the local variable list at a specified index.
Stloc_0 Pops the current value from the top of the evaluation stack and stores it in a the local variable list at index 0.
Stloc_1 Pops the current value from the top of the evaluation stack and stores it in a the local variable list at index 1.
Stloc_2 Pops the current value from the top of the evaluation stack and stores it in a the local variable list at index 2.
Stloc_3 Pops the current value from the top of the evaluation stack and stores it in a the local variable list at index 3.
Stloc_S Pops the current value from the top of the evaluation stack and stores it in a the local variable list at index (short form).
Stobj Copies a value of a specified type from the evaluation stack into a supplied memory address.
Stsfld Replaces the value of a static field with a value from the evaluation stack.
Sub Subtracts one value from another and pushes the result onto the evaluation stack.
Sub_Ovf Subtracts one integer value from another, performs an overflow check, and pushes the result onto the evaluation stack.
Sub_Ovf_Un Subtracts one unsigned integer value from another, performs an overflow check, and pushes the result onto the evaluation stack.
Switch Implements a jump table.
Tailcall Performs a postfixed method call instruction such that the current method's stack frame is removed before the actual call instruction is executed.
Throw Throws the exception object currently on the evaluation stack.
Unaligned Indicates that an address currently atop the evaluation stack might not be aligned to the natural size of the immediately following ldind, stind, ldfld, stfld, ldobj, stobj, initblk, or cpblk instruction.
Unbox Converts the boxed representation of a value type to its unboxed form.
Unbox_Any Converts the boxed representation of a type specified in the instruction to its unboxed form.
Volatile Specifies that an address currently atop the evaluation stack might be volatile, and the results of reading that location cannot be cached or that multiple stores to that location cannot be suppressed.
Xor Computes the bitwise XOR of the top two values on the evaluation stack, pushing the result onto the evaluation stack.

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Remarks

For a detailed description of the member opcodes, see the Common Language Infrastructure (CLI) documentation, especially "Partition III: CIL Instruction Set" and "Partition II: Metadata Definition and Semantics". The documentation is available online; see ECMA C# and Common Language Infrastructure Standards on MSDN and Standard ECMA-335 - Common Language Infrastructure (CLI) on the Ecma International Web site.

Version Information

Windows Phone OS

Supported in: 8.1, 8.0, 7.1

Platforms

Windows Phone

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

See Also

Reference

System.Reflection.Emit Namespace