Language.ArrayForth.Channel

Defines the basic operations for reading and writing through ports.

Each core has four ports connecting it to its neighbors. The cores around the edges have ports connected to IO devices. A Channel is just a type containing the four ports that you can write to or read from.

Documentation

data Channel

A channel representing the four communication directions a core may use. In practice, these will either be hooked up to other cores or to IO. Nothing represents no message; if there is a word, execution will block.

Constructors

Channel

Fields

right :: Maybe F18Word

down :: Maybe F18Word

left :: Maybe F18Word

up :: Maybe F18Word

Instances

Eq Channel

Show Channel

Monoid Channel

data Port

The four possible port directions.

Constructors

R

D

L

U

Instances

Bounded Port

Enum Port

Eq Port

Show Port

emptyChannel :: Channel

An empty channel has no reads or writes and doesn't block execution.

writePort

Arguments

:: F18Word

The address to write to. Only bits 5–8 are considered.

-> F18Word

The word to write to the channel.

-> Channel

The resulting channel, with any unused ports empty.

Write to the ports specified by the given memory address. This will clear all the channels not being written to (by setting them to Nothing).

The ports to use are specified by bits 5–8 of the address. These bits correspond respectively to up, left, down and right. Bits 5 and 7 are inverted—0 turns the channel *on*.

readPort :: F18Word -> Channel -> Maybe F18Word

Read the inputs from the ports specified by the given address. The address is handled the same way as in writePort. Returns Nothing if blocked on the read.

If more than one of the read ports has data, this currently just chooses the first one based on the right, down, left, up order. I don't know if this is the correct behavior—perhaps I should just xor them together or something?