91.

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ifeq

jump if zero

Jasmin Syntax

     ifeq <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

ifeq pops the top int off the operand stack. If the int equals zero, execution branches to the address (pc + branchoffset), where pc is the address of the ifeq opcode in the bytecode and branchoffset is a 16-bit signed integer parameter following the ifeq opcode in the bytecode. If the int on the stack does not equal 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     ifeq Label      ; if the value of local variable 1 is zero, jump to Label     return          ; return if local variable 1 is nonzero Label:     ; execution continues here if local variable 1 equals zero... 

Bytecode

Type	Description
u1	ifeq opcode = 0x99 (153)
s2	branchoffset

See Also

ifnull, iflt, ifle, ifne, 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).

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