144.

prev next contents

---

ifne

jump if nonzero

Jasmin Syntax

     ifne <label> 

<label> is a label name. To define the location of the label, use the <label> name followed by a colon:

 <label>: 

<label> then becomes associated the address of the following instruction. Labels can only be assigned one location in a method. On the other hand, a single <label> can be the target of multiple branch instructions.

Stack

Before	After
value	...
...

Description

ifne pops the top int off the operand stack. If the int does not equal zero, execution branches to the address (pc + branchoffset), where pc is the address of the ifne opcode in the bytecode and branchoffset is a 16-bit signed integer parameter following the ifne opcode in the bytecode. If the int on the stack equals zero, execution continues at the next instruction.

If you are using Jasmin, branchoffset is computed for you from the address of <label>.

Example

     iload_1         ; push the int value in local variable 1 onto the stack     ifne Label      ; if the value on the stack is nonzero, jump to Label     return          ; return if local variable 1 is zero Label:     ; execution continues here if local variable 1 does not equal zero... 

Bytecode

Type	Description
u1	ifne opcode = 0x9A (154)
s2	branchoffset

See Also

ifnull, ifeq, ifle, iflt, ifnonnull, ifgt, ifge

Notes

Addresses are measured in bytes from the start of the bytecode (i.e. address 0 is the first byte in the bytecode of the currently executing method).

---

prev next contents

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