138.

prev next contents
example

an example of an instruction entry

Jasmin Syntax
     example <param1> <param2> ... 
Stack

Before

After
item1
item2
item2
item1
...
...
Description

This page explains the format for instruction reference pages.

The first line on a reference page lists the name of an instruction and gives a brief synopsis of the instruction.

The 'Jasmin Syntax' section indicates the Jasmin assembler syntax for the instruction. In the example above, the instruction is shown with two parameters, one called <param1> and the other called <param2>. The 'Jasmin Syntax' also includes additional notes for Jasmin users.

The 'Stack' section describes the effect that the instruction has on the operand stack. It shows a symbolic representation of the stack state before and after the execution of the instruction. Each row in the tables represents a one-word entry on the stack. The first row represents the top of the stack. In the example above, its clear that the order of the top two words on the stack is reversed by the instruction.

The section you are reading is the 'Description' section, which gives details of how the instruction works and what its side effects are.

Example

 ; This section often contains examples illustrating how ; an instruction is used. ; Examples are written using the Jasmin assembler syntax. 
Exceptions

This section lists any exceptions generated by the instruction at runtime, and explains what causes each exception.

Bytecode

The 'Bytecode' section gives details on how the instruction is laid out in the bytecode of a class file. It shows a table listing the opcode for the instruction, as well as any additional parameters that follow the opcode in bytecode.

Type

Description
u1
This line usually shows the opcode for the instruction
u1
A 'u1' field is an unsigned 1-byte integer field
u2
A 'u2' field is an unsigned 2-byte integer field
u4
A 'u4' field is an unsigned 4-byte integer field
s1
A 's1' field is a signed 1-byte integer field
s2
A 's2' field is a signed 2-byte short integer field
s4
A 's4' field is a signed 4-byte integer field
See Also

The 'See Also' section lists related instructions that you should look at.

Notes

The 'Notes' section gives additional details that you should be aware of.


prev next contents
Java Virtual Machine, by Jon Meyer and Troy Downing, O'Reilly Associates


Java Virtual Machine
Java Virtual Machine (Java Series)
ISBN: 1565921941
EAN: 2147483647
Year: 1996
Pages: 171

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net