Copilot.Library.Stacks

This is a stream for a stack machine.

The stack is created from a specified depth, a specified start value, and three input streams:

• a pop signal which pops off the stack when true,
• a push signal which pushes the value from the push stream onto the stack when true,
• a push stream. The resultant stream is the top value of the stack.

In stack the push signal takes priority over the pop signal in the event that both are true in the same tick. This priority is reversed in stack'.

Here is an example sequence with one stack of each type, both depth 3 and starting value 0:

popSignal:   pushSignal:  pushValue:   stack:       stack':
false        true         100          0            0
false        true         101          100          100
true         true         102          101          101
true         false        103          100          102
true         false        104          0            101
true         false        105          0            100
true         false        106          0            0

Note the difference at the 4th tick after popSignal and pushSignal were both true. Note also that one cannot pop the start value off the stack - that is, the stack is never empty.

Documentation

stack

Arguments

:: (Integral a, Typed b)

=> a

Depth

-> b

Start value

-> Stream Bool

Pop signal

-> Stream Bool

Push signal

-> Stream b

Push stream

-> Stream b

Stack top

Stack stream in which the pop signal has precedence over the push signal in case both are true in the same tick

stack'

Arguments

:: (Integral a, Typed b)

=> a

Depth

-> b

Start value

-> Stream Bool

Pop signal

-> Stream Bool

Push signal

-> Stream b

Push stream

-> Stream b

Stack top

Stack stream in which the push signal has precedence over the pop signal in case both are true in the same tick