[Nestedvm] Possible to pass floats in call in NestedVM?

skinhat skinhat skinhat at hotmail.com
Tue Mar 19 20:22:34 EDT 2013

I looked at the SQLLite code and looks like they convert floats to 
strings and back. For example in NestedDB.java of SQLLite source its 

    synchronized int bind_double(long stmt, int pos, double v) throws SQLException {
        return bind_text(stmt, pos, Double.toString(v)); // TODO

   synchronized double value_double(Function f, int arg) throws SQLException {
        return Double.parseDouble(value_text(f, arg)); // TODO

I might have to do the same.

> Date: Tue, 19 Mar 2013 23:11:22 +0100
> From: fratz at inf.uni-konstanz.de
> To: skinhat at hotmail.com
> Subject: Re: [Nestedvm] Possible to pass floats in call in NestedVM?
> Hi,
> Thinking about it, it may be possible to do
> float foo = *((float *) &integer);
> in C to get that float back, but I never tried anything like that.
> However, there is a sqlite java interface (sqlite jdbc) that uses nestedvm,
> and that thing definitely has to pass floating point values to C, so it may
> be worth having a look at the relevant code.
> regards
> Matthias

Date: Mon, 18 Mar 2013 14:19:36 -0700
Subject: Re: [Nestedvm] Possible to pass floats in call in NestedVM?
From: ehrmann at gmail.com
To: skinhat at hotmail.com
CC: nestedvm at lists.hcoop.net

On Mon, Mar 18, 2013 at 1:04 PM, skinhat skinhat <skinhat at hotmail.com> wrote:

I have tried converting the float into raw int bits:

in runtime.java but just comes out to a huge integer.
  That's probably correct. Floats are stored very differently than ints, and the int version of a float will always look nothing like the float. The only exception I can think of is positive zero looking like an int zero. Negative zero looks completely different.
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