18.

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if_icmpeq

jump if two integers are equal

Jasmin Syntax

     if_icmpeq <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
value1	...
value2
...

Description

if_icmpeq pops the top two ints off the stack and compares them. If the two integers are equal, execution branches to the address (pc + branchoffset), where pc is the address of the if_icmpeq opcode in the bytecode and branchoffset is a 16-bit signed integer parameter following the if_icmpeq opcode in the bytecode. If the integers are not equal, execution continues at the next instruction.

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

Example

     bipush 2        ; push the int 2 onto the stack     iload_1         ; push the int value in local variable 1 onto the stack     if_icmpeq Label ; if the value of local variable 1 equals 2, jump to Label     return          ; return if not equal Label:     ; execution continues here if local variable 1 equals 2... 

Bytecode

Type	Description
u1	if_icmpeq opcode = 0x9F (159)
s2	branchoffset

See Also

if_icmpne, if_icmplt, if_icmpgt, if_icmple, if_icmpge

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