Create an array in asm java compiler

Question

Iam trying to create an array of integers using bytecode instructions

Any ideas how to do it?

Yes but the problem is i do not know how to syntax it for example it doesn't say how to put the size of the array. — Tony, Jun 8 '13 at 0:57
@Tony. You may write actual java code, compile and then use javap (docs.oracle.com/javase/7/docs/technotes/tools/windows/…) to get the bytecode. — Jayan, Jun 8 '13 at 1:13

Antimony · Answer 1 · 2013-06-08 16:46:57Z

up vote 1 down vote

The size of the array is popped off the stack, so you need to push it onto the stack first.

To create a 1000 element array for instance, you could do something like

sipush 1000
newarray int

Edit: I just noticed that there's a standard lib function to fill arrays. That makes things much easier.

sipush 1000
newarray int
dup
iconst_1
invokestatic java/util/Arrays fill ([II)V

answered Jun 8 '13 at 1:57

Antimony
15.7k12247

ok thanks. And if you want for example to initialise the array with the number 1 after the creation what i will have to do? – Tony Jun 8 '13 at 2:00

You mean initialize every element of the array to 1? You'd have to write a loop. – Antimony Jun 8 '13 at 5:16

Can you show me some code using instructions of asm to understand how to do it? – Tony Jun 8 '13 at 11:53

@Tony I just posted an example of how to do it with Arrays.fill. – Antimony Jun 8 '13 at 16:47

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