F18 Variables

Variables on the F18 are not like regular Forth variables. Usually a variable is a word returning the address of its value used along with fetch (@) and store (!) words. On the F18 the idiomatic approach is to have individual variable-specific fetch and store words. Greg Bailey explains it nicely here: Constants Let’s start with constants….

1

Multiply-step Instruction

Fourth in a series on colorForth and GreenArrays hardware. This time, how the multiply-step instruction works on the F18. Bit Twiddling is Fun! Here’s a bit-twiddly interview question for you: Design an algorithm to multiply fixnum integers in O(log n) time using only addition. This may come in handy given that the F18 doesn’t have…

1

The Beautiful Simplicity of colorForth

colorForth As much fun as hand packing instructions was in the last post, that was tedious. Let’s move on to colorForth. Don’t worry too much about what the code above does (prints “colorForth rocks!”). It compiles to this: Isn’t the source beautiful? So colorful! The colors are not merely syntax highlighting. They drive the semantics! They are…

6

Programming the F18

Programming the F18 As we saw in the last post, the GA144 chip is an array of 144 tiny computers or “nodes”. We tend not to call them “cores” because they are really more independent than that. Programming these interconnected nodes is something like working with agents or CSP. Each is an instance of the…

14

Chuck Moore’s Creations

This is the beginning of a series: Programming the F18 Beautiful Simplicity of colorForth Multiply-step Instruction Simple Variables When I heard that Chuck Moore was speaking at Strange Loop this year I just had to go. His talk yesterday was excellent! I’m not going to summarize it here. The talk will be online soon enough….

7