JVM, Class Files, and the CLEmitter - Introduction to Compiler Construction in a Java World - page 338

Mnemonic Operation Operand Stack

dup_x1 Duplicate the top operand
stack value and insert two
values down

;value2;value1 ) ;value1;value2;value1

dup_x2 Duplicate the top operand
stack value and insert two
or three values down

;value3;value2;value1 )
;value1;value3;value2;value1

;value2;value1 ) ;value1;value2;value1

dup2 Duplicate the top one or
two operand stack values

;value2;value1 )

;value2;value1;value2;value1

;value ) ;value;value

dup2_x1 Duplicate the top one or
two operand stack values
and insert two or three
values down

;value3;value2;value1 )
;value2;value1;value3;value2;value1

;value2;value1 ) ;value1;value2;value1

dup2_x2 Duplicate the top one or
two operand stack values
and insert two, three, or
four values down

;value4;value3;value2;value1 )
;value2;value1;value4;value3;value2;value1

;value3;value2;value1 )
;value1;value3;value2;value1

;value3;value2;value1 )
;value2;value1;value3;value2;value1

;value2;value1 ) ;value1;value2;value1

swap Swap the top two operand
stack values

;value2;value1 ) ;value1;value2

The above instructions can be added to the code section of a method by sending the
CLEmitter instance the following message:

publicvoidaddNoArgInstruction(intopcode)

where opcode is the mnemonic of the instruction to be added.

D.5.12 Other Instructions

Mnemonic Operation Operand Stack

nop Do nothing No change
athrow Throw exception or error ;objectref ) ;objectref
monitorenter Enter monitor for object ;objectref )
monitorexit Exit monitor for object ;objectref )

The above instructions can be added to the code section of a method by sending the
CLEmitter instance the following message:

publicvoidaddNoArgInstruction(intopcode)