🚀 go-pugleaf

In article <41842@cup.portal.com> waw@cup.portal.com (Warren Charles Wong) writes:
>Hello,
>
>Recently, I've come across some terminology regarding floating-pt
>algorithms used in PostScript character generations.  A popular one
>I've heard is the "Cordix" algorithm...

That's CORDIC (an acronym). I don't have the book here but I believe
there is a reprint of the original paper by Walthers in 'Computer
Aritihmetic', Vol. I, Swartzlander, Ed.

CORDIC is a family of algorithms for computing elementary functions
(trig, hyperblolic trig, polar to/from rectangular coordinates,
rotations, linear transformations, perhaps others). The algorithms are
iterative, and take one iteration per result bit. By my thinking, this
is slow, but speed is relative. On the other hand, the only hardware
required is an adder and a shift by one place. CORDIC has been used
in floating point coprocessors (Motorola 68881 I believe) and hand held
calculators (HP I believe).

If you already have fast floating point hardware, there are probably faster
algorithms. However, if you only have an integer unit, these may be
interesting.

---

Michael Weaver.