✎ javacard:jcvm:2.3.2.3_static_restrictions_on_bytecodes [wiki]

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=== 2.3.2.3 Static Restrictions on Bytecodes ===

A **class** file must conform to the following restrictions on the static form of bytecodes. 

== ldc_ldc_w ==

The ****ldc**** and ****ldc****_w bytecodes can only be used to load integer constants. The constant pool entry at index must be a **CONSTANT_Integer** entry. If a program contains an ****ldc**** or ****ldc****_w instruction that is used to load an integer value less than  -32768 or greater than 32767, that program will require the optional int instructions ([[2.2.3.1_Integer Data Type| Section 2.2.3.1, Integer Data Type]]). 

== lookupswitch ==

The value of the npairs operand must be less than 65536. This limit is far greater than the limit imposed by the maximum size of methods ([[2.2.4.4_Methods| Section 2.2.4.4, Methods]]). If a program contains a lookupswitch instruction that uses keys of type int, that program will require the optional int instructions ([[2.2.3.1_Integer Data Type| Section 2.2.3.1, Integer Data Type]]). Otherwise, key values must be in the range  -32768 to 32767. 

== tableswitch ==

The bytecode can contain at most 65536 cases. This limit is far greater than the limit imposed by the maximum size of methods ([[2.2.4.4_Methods| Section 2.2.4.4, Methods]]). If a program does not use the optional int instructions ([[2.2.3.1_Integer Data Type| Section 2.2.3.1, Integer Data Type]]), the values of the **high** and **low** operands must both be at least -32768 and at most 32767. 

== wide ==

The **wide** bytecode can only be used with an **iinc** instruction.

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