iget<kind>

Purpose

Perform the identified object instance field operation with the identified field, loading or storing into the value register.

Note: These opcodes are reasonable candidates for static linking, altering the field argument to be a more direct offset.

Details

Op & Format	Mnemonic / Syntax	Arguments
52..58 22c	iinstanceop vA, vB, field@CCCC 52: iget 53: iget-wide 54: iget-object 55: iget-boolean 56: iget-byte 57: iget-char 58: iget-short	`A:` dest value register or pair; (4 bits) `B:` object register (4 bits) `C:` instance field reference index (16 bits)

Constraints

A and B must be valid register indices in the current stackframe.
For the -wide variant, also A+1 must be a valid register index in the current stackframe.
Register vB must contain an object reference.
C must be a valid index into the field reference pool.
The field must be an instance field. The type of the field denoted by C must match the variant of the instruction.

Behavior

The value of the given instance field is read from the given object and moved into the given register vA, that is, vA'=<object>.<field>.
If v(A-1) is the lower half of a register pair, v(A-1)' becomes undefined.
For all but the -wide variant, if v(A+1) is the upper half of a register pair, v(A+1)' becomes undefined.
For the -wide variant, if v(A+2) is the upper half of a register pair, v(A+2)' becomes undefined.

Exceptions

NullPointerException if object is null.
IllegalAccessException if <object>.<field> is not visible from the current context according to the usual visibility and access rules of the Java programming language.