Class: HDLRuby::High::Std::PriorityArbiterT

Inherits:
ArbiterT
  • Object
show all
Defined in:
lib/HDLRuby/std/sequencer_sync.rb

Overview

Describes a priority-based arbiter.

Direct Known Subclasses

PriorityMonitorT

Instance Method Summary collapse

Methods inherited from ArbiterT

#<=, #call, #select

Constructor Details

#initialize(name, tbl = nil, *sigs, &ruby_block) ⇒ PriorityArbiterT

Create a new priority-based arbiter named +name+ with priority table +tbl+ or priority algorithm +ruby_block+ for shared signals +sigs+.



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# File 'lib/HDLRuby/std/sequencer_sync.rb', line 197

def initialize(name, tbl = nil, *sigs, &ruby_block)
    super(name,*sigs)
    # Set the priority policy.
    self.policy(tbl,&ruby_block)
    # Create the name of the access procedure sub.
    @name_sub = HDLRuby.uniq_name(:"#{name}_sub")
end

Instance Method Details

#add_point ⇒ Object

Add a point.



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# File 'lib/HDLRuby/std/sequencer_sync.rb', line 223

def add_point
    point = super # The point is added by the parent class.
    # Update the access procedure.
    name_sub = @name_sub
    this = self
    size = @size
    acquires = @acquires
    priority = @priority
    HDLRuby::High.cur_system.open do
        sub(name_sub) do
            seq do
                if(size == 1) then
                    # Anyway, only one accesser.
                    this.select(0)
                else
                    hif(priority.(acquires,0)) do
                        this.select(0)
                    end
                    (1..size-1).each do |i|
                        helsif(priority.(acquires,i)) do
                            this.select(i)
                        end
                    end
                    helse do # No acquire at all, select the first point.
                        this.select(0)
                    end
                end
            end
        end
    end
    return point
end

#policy(tbl = nil, &ruby_block) ⇒ Object

Set the policy either using a priority table +tbl+ by directly providing the priority algorithm through +ruby_block+



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# File 'lib/HDLRuby/std/sequencer_sync.rb', line 207

def policy(tbl = nil, &ruby_block)
    # By default the priority table is the points declaration order.
    if !tbl && ruby_block == nil then
        @priority = proc { |acquires,i| acquires[i] == 1 }
    elsif tbl then
        @priority = proc do |acquires,i| 
            pri = tbl[i]
            raise "Invalid priority index: #{i}" unless pri
            acquires[pri] == 1
        end
    else
        @priority = ruby_block
    end
end