[Cryptography Team] Implementing Reed Solomon plugins

[Robert Withers]

I have the outlined definitions of 2 Plugins, 1 for RSErasurePlugin and 1 for RSFECPlugin. They are published to Cryptography. I am trying to understand how to write primitives to get the work done. Any and All assistance MOST WELCOME! Let's get her done!

I believe I have properly implemented the #declareCVarsIn: and initialized for both plugins.

I am looking at a primitive implementation in RSFECPlugin>>#primitiveInverseWithSize. A few questions: am I grabbing the stack arguments correctly? Testing their values correctly? Correctly calling a method to do the work. Manipulating the stack to setup a return value???

I am doing this...correct?

> self pop: 2 thenPushInteger: multiplied.
> ^interpreterProxy methodReturnInteger: multiplied.

---

> primitiveInverseWithSize
> <export: true>
> <var: 'a' declareC: 'unsigned short' >
> <var: 'size' declareC: 'unsigned short' >
>
> | a size multiplied |
> interpreterProxy methodArgumentCount = 2
> ifFalse: [ ^interpreterProxy primitiveFailFor: PrimErrBadNumArgs ].
> a := interpreterProxy stackIntegerValue: 0.
> size := interpreterProxy stackIntegerValue: 1.
>
> ((interpreterProxy isBytes: a)
> and: [ (interpreterProxy stSizeOf: a) = 2 ])
> ifFalse: [ ^interpreterProxy primitiveFailFor: PrimErrBadArgument ].
> ((interpreterProxy isBytes: size)
> and: [ (interpreterProxy stSizeOf: a) = 2 ])
> ifFalse: [ ^interpreterProxy primitiveFailFor: PrimErrBadArgument ].
> multiplied := self inverse: a withSize: size.
> self pop: 2 thenPushInteger: multiplied.
> ^interpreterProxy methodReturnInteger: multiplied.

And:

> inverse: a withSize: size
>
> (a = 0)
> ifTrue: [RSErasureIllegalArgumentError signal: 'the argument is zero'].
> ^ expTable at: (size - ((logTable at: (a + 1)) - 1)).

--
---
Kindly,
Robert
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.squeakfoundation.org/pipermail/cryptography/attachments/20210527/446bfd91/attachment.html>