CIL opcodes are one or more bytes long; they can be followed by zero or more operand bytes. All opcodes whose first byte lies in the ranges 0x00 through 0xEF, or 0xFC through 0xFF are reserved for standardization. Opcodes whose first byte lies in the range 0xF0 through 0xFB inclusive, are available for experimental purposes. The use of experimental opcodes in any method renders the method invalid and hence unverifiable.
The currently defined encodings are specified in Table 1: Opcode Encodings.
| Opcode | Instruction |
|---|---|
| 0x00 | nop |
| 0x01 | break |
| 0x02 | ldarg.0 |
| 0x03 | ldarg.1 |
| 0x04 | ldarg.2 |
| 0x05 | ldarg.3 |
| 0x06 | ldloc.0 |
| 0x07 | ldloc.1 |
| 0x08 | ldloc.2 |
| 0x09 | ldloc.3 |
| 0x0A | stloc.0 |
| 0x0B | stloc.1 |
| 0x0C | stloc.2 |
| 0x0D | stloc.3 |
| 0x0E | ldarg.s |
| 0x0F | ldarga.s |
| 0x10 | starg.s |
| 0x11 | ldloc.s |
| 0x12 | ldloca.s |
| 0x13 | stloc.s |
| 0x14 | ldnull |
| 0x15 | ldc.i4.m1 |
| 0x16 | ldc.i4.0 |
| 0x17 | ldc.i4.1 |
| 0x18 | ldc.i4.2 |
| 0x19 | ldc.i4.3 |
| 0x1A | ldc.i4.4 |
| 0x1B | ldc.i4.5 |
| 0x1C | ldc.i4.6 |
| 0x1D | ldc.i4.7 |
| 0x1E | ldc.i4.8 |
| 0x1F | ldc.i4.s |
| 0x20 | ldc.i4 |
| 0x21 | ldc.i8 |
| 0x22 | ldc.r4 |
| 0x23 | ldc.r8 |
| 0x25 | dup |
| 0x26 | pop |
| 0x27 | jmp |
| 0x28 | call |
| 0x29 | calli |
| 0x2A | ret |
| 0x2B | br.s |
| 0x2C | brfalse.s |
| 0x2D | brtrue.s |
| 0x2E | beq.s |
| 0x2F | bge.s |
| 0x30 | bgt.s |
| 0x31 | ble.s |
| 0x32 | blt.s |
| 0x33 | bne.un.s |
| 0x34 | bge.un.s |
| 0x35 | bgt.un.s |
| 0x36 | ble.un.s |
| 0x37 | blt.un.s |
| 0x38 | br |
| 0x39 | brfalse |
| 0x3A | brtrue |
| 0x3B | beq |
| 0x3C | bge |
| 0x3D | bgt |
| 0x3E | ble |
| 0x3F | blt |
| 0x40 | bne.un |
| 0x41 | bge.un |
| 0x42 | bgt.un |
| 0x43 | ble.un |
| 0x44 | blt.un |
| 0x45 | switch |
| 0x46 | ldind.i1 |
| 0x47 | ldind.u1 |
| 0x48 | ldind.i2 |
| 0x49 | ldind.u2 |
| 0x4A | ldind.i4 |
| 0x4B | ldind.u4 |
| 0x4C | ldind.i8 |
| 0x4D | ldind.i |
| 0x4E | ldind.r4 |
| 0x4F | ldind.r8 |
| 0x50 | ldind.ref |
| 0x51 | stind.ref |
| 0x52 | stind.i1 |
| 0x53 | stind.i2 |
| 0x54 | stind.i4 |
| 0x55 | stind.i8 |
| 0x56 | stind.r4 |
| 0x57 | stind.r8 |
| 0x58 | add |
| 0x59 | sub |
| 0x5A | mul |
| 0x5B | div |
| 0x5C | div.un |
| 0x5D | rem |
| 0x5E | rem.un |
| 0x5F | and |
| 0x60 | or |
| 0x61 | xor |
| 0x62 | shl |
| 0x63 | shr |
| 0x64 | shr.un |
| 0x65 | neg |
| 0x66 | not |
| 0x67 | conv.i1 |
| 0x68 | conv.i2 |
| 0x69 | conv.i4 |
| 0x6A | conv.i8 |
| 0x6B | conv.r4 |
| 0x6C | conv.r8 |
| 0x6D | conv.u4 |
| 0x6E | conv.u8 |
| 0x6F | callvirt |
| 0x70 | cpobj |
| 0x71 | ldobj |
| 0x72 | ldstr |
| 0x73 | newobj |
| 0x74 | castclass |
| 0x75 | isinst |
| 0x76 | conv.r.un |
| 0x79 | unbox |
| 0x7A | throw |
| 0x7B | ldfld |
| 0x7C | ldflda |
| 0x7D | stfld |
| 0x7E | ldsfld |
| 0x7F | ldsflda |
| 0x80 | stsfld |
| 0x81 | stobj |
| 0x82 | conv.ovf.i1.un |
| 0x83 | conv.ovf.i2.un |
| 0x84 | conv.ovf.i4.un |
| 0x85 | conv.ovf.i8.un |
| 0x86 | conv.ovf.u1.un |
| 0x87 | conv.ovf.u2.un |
| 0x88 | conv.ovf.u4.un |
| 0x89 | conv.ovf.u8.un |
| 0x8A | conv.ovf.i.un |
| 0x8B | conv.ovf.u.un |
| 0x8C | box |
| 0x8D | newarr |
| 0x8E | ldlen |
| 0x8F | ldelema |
| 0x90 | ldelem.i1 |
| 0x91 | ldelem.u1 |
| 0x92 | ldelem.i2 |
| 0x93 | ldelem.u2 |
| 0x94 | ldelem.i4 |
| 0x95 | ldelem.u4 |
| 0x96 | ldelem.i8 |
| 0x97 | ldelem.i |
| 0x98 | ldelem.r4 |
| 0x99 | ldelem.r8 |
| 0x9A | ldelem.ref |
| 0x9B | stelem.i |
| 0x9C | stelem.i1 |
| 0x9D | stelem.i2 |
| 0x9E | stelem.i4 |
| 0x9F | stelem.i8 |
| 0xA0 | stelem.r4 |
| 0xA1 | stelem.r8 |
| 0xA2 | stelem.ref |
| 0xA3 | ldelem |
| 0xA4 | stelem |
| 0xA5 | unbox.any |
| 0xB3 | conv.ovf.i1 |
| 0xB4 | conv.ovf.u1 |
| 0xB5 | conv.ovf.i2 |
| 0xB6 | conv.ovf.u2 |
| 0xB7 | conv.ovf.i4 |
| 0xB8 | conv.ovf.u4 |
| 0xB9 | conv.ovf.i8 |
| 0xBA | conv.ovf.u8 |
| 0xC2 | refanyval |
| 0xC3 | ckfinite |
| 0xC6 | mkrefany |
| 0xD0 | ldtoken |
| 0xD1 | conv.u2 |
| 0xD2 | conv.u1 |
| 0xD3 | conv.i |
| 0xD4 | conv.ovf.i |
| 0xD5 | conv.ovf.u |
| 0xD6 | add.ovf |
| 0xD7 | add.ovf.un |
| 0xD8 | mul.ovf |
| 0xD9 | mul.ovf.un |
| 0xDA | sub.ovf |
| 0xDB | sub.ovf.un |
| 0xDC | endfinally |
| 0xDD | leave |
| 0xDE | leave.s |
| 0xDF | stind.i |
| 0xE0 | conv.u |
| 0xFE 0x00 | arglist |
| 0xFE 0x01 | ceq |
| 0xFE 0x02 | cgt |
| 0xFE 0x03 | cgt.un |
| 0xFE 0x04 | clt |
| 0xFE 0x05 | clt.un |
| 0xFE 0x06 | ldftn |
| 0xFE 0x07 | ldvirtftn |
| 0xFE 0x09 | ldarg |
| 0xFE 0x0A | ldarga |
| 0xFE 0x0B | starg |
| 0xFE 0x0C | ldloc |
| 0xFE 0x0D | ldloca |
| 0xFE 0x0E | stloc |
| 0xFE 0x0F | localloc |
| 0xFE 0x11 | endfilter |
| 0xFE 0x12 | unaligned. |
| 0xFE 0x13 | volatile. |
| 0xFE 0x14 | tail. |
| 0xFE 0x15 | initobj |
| 0xFE 0x16 | constrained. |
| 0xFE 0x17 | cpblk |
| 0xFE 0x18 | initblk |
| 0xFE 0x19 | no. |
| 0xFE 0x1A | rethrow |
| 0xFE 0x1C | sizeof |
| 0xFE 0x1D | refanytype |
| 0xFE 0x1E | readonly. |