VM Spec

The Java^TM Virtual Machine Specification

baload

Operation Load byte or boolean from array

baload

Forms baload = 51 (0x33)

Stack ..., arrayref, index ..., value

Description The arrayref must be of type reference and must refer to an array whose components are of type byte or of type boolean. The index must be of type int. Both arrayref and index are popped from the operand stack. The byte value in the component of the array at index is retrieved, sign-extended to an int value, and pushed onto the top of the operand stack.

Runtime Exceptions If arrayref is null, baload throws a NullPointerException.

Otherwise, if index is not within the bounds of the array referenced by arrayref, the baload instruction throws an ArrayIndex-OutOfBounds-Exception.

Notes The baload instruction is used to load values from both byte and boolean arrays. In Sun's implementation of the Java Virtual Machine, boolean arrays (arrays of type T_BOOLEAN; see §3.1 and the description of the newarray instruction) are implemented as arrays of 8-bit values. Other implementations may implement packed boolean arrays; the baload instruction of such implementations must be used to access those arrays.

bastore

Operation Store into byte or boolean array

bastore

Forms bastore = 84 (0x54)

Stack ..., arrayref, index, value ...

Description The arrayref must be of type reference and must refer to an array whose components are of type byte or of type boolean. The index and the value must both be of type int. The arrayref, index, and value are popped from the operand stack. The int value is truncated to a byte and stored as the component of the array indexed by index.

Runtime Exceptions If arrayref is null, bastore throws a NullPointerException.

Otherwise, if index is not within the bounds of the array referenced by arrayref, the bastore instruction throws an ArrayIndexOutOfBoundsException.

Notes The bastore instruction is used to store values into both byte and boolean arrays. In Sun's implementation of the Java Virtual Machine, boolean arrays (arrays of type T_BOOLEAN; see §3.1 and the description of the newarray instruction) are implemented as arrays of 8-bit values. Other implementations may implement packed boolean arrays; the bastore instruction of such implementations must be used to store into those arrays.

bipush

Operation Push byte

bipush
byte

Forms bipush = 16 (0x10)

Stack ... ..., value

Description The immediate byte is sign-extended to an int, and the resulting value is pushed onto the operand stack.

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