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Can someone please explain the syntax/function of MFD?

I need to find a given matrix element to implement Shanks square form factorization method.
From the code I'd say: ( y mat -> r )
Where mat is a matrix descriptor and y is the element you search.


/* Find a specified element in a matrix
            x[<->] Y
m_find_loop::       x=?[->]Y
            JMP m_found
            ISG Y
            JMP m_find_loop
m_found::       DROP
To post #2:

Thank you.

I don't understand r.

For 5,6,7,8 stored in registers 20 to 23

stack y: 55 x: 20.0401 returns 24.02301


stack y: 7 x: 20.0401 returns 22.02301

Presumably the second result indicates "found"? How should this result be interpreted?
You probably want the index of the element. The matrix descriptor is still in the last x register. Therefore you can use:
For 7 you get (x, y) = (3, 1). For 55 you get an Error: Out of range.
To post #4:

Thank you & yes that is the info I needed.

Will now get to work on Shanks SQFF.
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