lstore <varnum> or wide lstore <varnum>In the first form, <varnum> is an unsigned integer in the range 0 to 0xFF. In the second (wide) form, <varnum> is an unsigned integer in the range 0 to 0xFFFE.
Stack Before
Description After long-word1 ... long-word2 ...
lstore pops a two-word long integer off the operand stack and stores it in a local variable. It takes a single parameter, <varnum>, an unsigned integer indicating which local variable to use.
Since long integers are 64-bits wide, and each local variable can only hold up to 32 bits Java uses two consecutive local variables, <varnum> and <varnum> + 1 to store a long. So lstore <varnum> actually modifies the values of both <varnum> (which is set to long-word1) and <varnum> + 1 (which is set to long-word2).
Both <varnum> and <varnum> + 1 must be valid local variable numbers in the current frame, and together they must be holding a long.
Remember that attempting to treat two-word values as two independent single-word values will produce a verification error. So trying to retrieve <varnum> or <varnum> + 1 independently (e.g. iload <varnum>) will produce a verification error. Similarly, if you store a value other than a long in <varnum>, then <varnum> + 1 becomes invalidated until a new value is stored in it.
Example
ldc2_w 10 ; push the long integer 10 onto the stack lstore 3 ; pop 10 off of the stack and store it in local variables 3 and 4Bytecode
For local variable numbers in the range 0-255, use:
Type | Description |
u1 | lstore opcode = 0x37 (55) |
u1 | <varnum> |
Type | Description |
u1 | wide opcode = 0xC4 (196) |
u1 | lstore opcode = 0x37 (55) |
u2 | <varnum> |
istore, fstore, dstore, astore, wide