Re: [Pnet-developers] runtime/verifier questions again

[Rhys Weatherley]

On Tuesday 10 August 2004 10:04 pm, Andre 'Ilu' Seidelt wrote:

> It seems the values are stored different depending on
> their usage (calculation/local variable/parameter).

Calculations on floating-point values are always performed using 
ILNativeFloat, as per the ECMA spec.  Local variables are stored as ILFloat 
or ILDouble, and converted to/from ILNativeFloat during calculations.

Method parameters are pushed as ILNativeFloat, and then down-converted to 
either ILFloat or ILDouble inside the method ("ffixup" and "dfixup" 
instructions in CVM take care of this).

> Are there 'rules' how values are stored on the stack for
> the Execution-, the Parameter- and the LocalVariableStack?

See "CVMEntryAllocArgs" and "CVMEntryAllocLocals" in "cvmc_setup.c" for the 
details on how the method frame is laid out.

> I think this means the following:
> <15>    : The instance of 'Test' used by firstMethod as this
> <14>    : lower int border
> <13>    : seems to be an ILFloat (local variable of firstMethod)
> <12-11> : seems to be an ILDouble ( "" )
> <10>    : upper int border
> <09>    : The instance of 'Test' param to OtherCall as this
> <08>    : lower int border
> <07-05> : what is this? an ILNativeFloat?
> <05-02> : what is this? an ILNativeFloat?
> <01>    : upper int border
>
> The values in <02> and <05> look like pointers to something?

They are ILNativeFloat values, as you surmised.  On x86, ILNativeFloat values 
occupy 12 bytes, or 3 stack words.

Cheers,

Rhys.