Class: HDLRuby::High::Std::SequencerT

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

Overview

Describes a sequencer block.

Constant Summary collapse

@@current =

The current sequencer.

nil

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(ev, start, &ruby_block) ⇒ SequencerT

Create a new sequencer block synchronized on +ev+ and starting on +start+



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# File 'lib/HDLRuby/std/sequencer.rb', line 27

def initialize(ev,start,&ruby_block)
    this = self
    # Process the arguments.
    ev = ev.posedge unless ev.is_a?(Event)
    if start.is_a?(Event) then
        start = start.type == :posedge ? start.ref : ~start.ref
    end
    # Create the fsm from the block.
    @fsm = fsm(ev,start,:seq)
    # On reset (start) tell to go to the first state.
    run = HDLRuby::High.cur_system.inner(HDLRuby.uniq_name(:run) => 0)
    @fsm.reset do
        # HDLRuby::High.top_user.instance_exec do
        #     next_state_sig <= this.start_state_value
        # end
        run <= 1
    end

    # The status stack of the sequencer.
    @status = [ {} ]
    # Creates the namespace to execute the sequencer deescription 
    # block in.
    @namespace = Namespace.new(self)

    # The end state is actually 0, allows to sequencer to be stable
    # by default.
    @fsm.default { run <= 0 }
    @end_state = @fsm.state { }
    @end_state.gotos << proc do
        HDLRuby::High.top_user.instance_exec do
            hif(run) { next_state_sig <= this.start_state_value }
            helse { next_state_sig <= this.end_state_value }
        end
    end
    # Record the start and end state values.
    # For now, the start state is the one just following the end state.
    @end_state_value = @end_state.value
    @start_state_value = @end_state_value + 1
    # puts "end_state_value=#{@end_state_value}"

    # Process the ruby_block.
    @@current = self
    HDLRuby::High.space_push(@namespace)
    blk = HDLRuby::High::Block.new(:seq,&ruby_block)
    HDLRuby::High.space_pop

    # If the block is not empty, add it as last state.
    this = self
    if blk.each_statement.any? then
        st = @fsm.state do
            this.fill_top_user(blk)
        end
    end
    # # Ends the fsm with an infinite loop state.
    # st = @fsm.state {}
    # st.gotos << proc do
    #     HDLRuby::High.top_user.instance_exec do
    #         # next_state_sig <= st.value
    #         next_state_sig <= EndStateValue
    #     end
    # end

    # Build the fsm.
    @fsm.build
end

Instance Attribute Details

#end_state_value ⇒ Object (readonly)

The start and end states values.



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# File 'lib/HDLRuby/std/sequencer.rb', line 23

def end_state_value
  @end_state_value
end

#start_state_value ⇒ Object (readonly)

The start and end states values.



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# File 'lib/HDLRuby/std/sequencer.rb', line 23

def start_state_value
  @start_state_value
end

Class Method Details

.current ⇒ Object

Get the sequencer currently processing.



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# File 'lib/HDLRuby/std/sequencer.rb', line 18

def self.current
    @@current
end

Instance Method Details

#fill_top_user(blk) ⇒ Object

Fills the top user with the content of block +blk+.



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# File 'lib/HDLRuby/std/sequencer.rb', line 304

def fill_top_user(blk)
    # Fill the current block with blk content.
    blk.each_statement do |stmnt|
        stmnt.parent = nil
        HDLRuby::High.top_user.add_statement(stmnt)
    end
end

#loop_status ⇒ Object

Get the closest loop status in the status stack. NOTE: raises an exception if there are not swhile state.



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# File 'lib/HDLRuby/std/sequencer.rb', line 95

def loop_status
    i = @status.size-1
    begin
       status = @status[i -= 1]
       raise "No loop for sbreak." unless status
    end while(!status[:loop])
    return status
end

#sbreak ⇒ Object

Breaks current iteration.



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# File 'lib/HDLRuby/std/sequencer.rb', line 126

def sbreak
    # Mark a step.
    st = self.step
    # Tell there is a break to process.
    # Do that in the first loop status met.
    status = self.loop_status
    status[:sbreaks] ||= []
    status[:sbreaks] << st
    return st
end

#scontinue ⇒ Object

Continues current iteration.



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# File 'lib/HDLRuby/std/sequencer.rb', line 138

def scontinue
    # Mark a step.
    st = self.step
    # Go to the begining of the iteration, i.e., the first loop
    # status met.
    status = self.loop_status
    st.gotos << proc do
        HDLRuby::High.top_user.instance_exec do
            next_state_sig <= status[:loop]
        end
    end
    return st
end

#selse(&ruby_block) ⇒ Object

Create a sequential else statement.



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# File 'lib/HDLRuby/std/sequencer.rb', line 192

def selse(&ruby_block)
    # Create a state to be executed if the previous condition is
    # not met.
    @status.push({})
    no_name = HDLRuby.uniq_name("no")
    no_blk = HDLRuby::High::Block.new(:seq,&ruby_block)
    @status.pop
    this = self
    no = @fsm.state(no_name) { this.fill_top_user(no_blk) }
    # Adds a goto to the previous if yes state for jumping the no state.
    yes = @status.last[:sif_yes]
    raise "Cannot use selse here." unless yes
    cond = @status.last[:condition]
    yes.gotos << proc do
        HDLRuby::High.top_user.instance_exec do
            next_state_sig <= no.value + 1
        end
    end
    return no
end

#sfor(expr, &ruby_block) ⇒ Object

Create a sequential for statement iterating over the elements of +expr+.



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# File 'lib/HDLRuby/std/sequencer.rb', line 295

def sfor(expr,&ruby_block)
    # Ensures there is a ruby block to avoid returning an enumerator
    # (returning an enumerator would be confusing for a for statement).
    ruby_block = proc {} unless ruby_block
    expr.seach.with_index(&ruby_block)
end

#sif(cond, &ruby_block) ⇒ Object

Create a sequential if statement on +cond+.



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# File 'lib/HDLRuby/std/sequencer.rb', line 167

def sif(cond, &ruby_block)
    # Mark a step.
    st = self.step
    # Remember the condition.
    @status.last[:condition] = cond
    # Create a state to be executed if the condition is met.
    @status.push({})
    yes_name = HDLRuby.uniq_name("yes")
    yes_blk = HDLRuby::High::Block.new(:seq,&ruby_block)
    @status.pop
    this = self
    yes = @fsm.state(yes_name) { this.fill_top_user(yes_blk) }
    # Add a goto to the previous state.
    st.gotos << proc do
        HDLRuby::High.top_user.instance_exec do
            hif(cond) { next_state_sig <= st.value + 1 }
            helse { next_state_sig <= yes.value + 1 }
        end
    end
    # Remeber the if yes state for being able to add else afterward.
    @status.last[:sif_yes] = yes
    return st
end

#sloop(&ruby_block) ⇒ Object

Create a sequential infinite loop statement.



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# File 'lib/HDLRuby/std/sequencer.rb', line 289

def sloop(&ruby_block)
    self.swhile(nil,&ruby_block)
end

#step ⇒ Object

Mark a step.



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# File 'lib/HDLRuby/std/sequencer.rb', line 107

def step
    # Create a new block from all the statements in the previous block.
    blk = HDLRuby::High::Block.new(:seq) {}
    # Get all the statements of the builder block.
    stmnts = HDLRuby::High.cur_block.instance_variable_get(:@statements)
    # Add all the statements to blk.
    stmnts.each { |stmnt| stmnt.parent = nil; blk.add_statement(stmnt) }
    # Remove them from the builder block.
    stmnts.clear

    # Create a state for this block.
    this = self
    st = @fsm.state { this.fill_top_user(blk) }
    # # Set the previous step in sequence.
    # @status.last[:state] = st
    return st
end

#sterminate ⇒ Object

Terminates the sequencer.



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# File 'lib/HDLRuby/std/sequencer.rb', line 153

def sterminate
    # Mark a step.
    st = self.step
    # Adds a goto the ending state.
    this = self
    st.gotos << proc do
        HDLRuby::High.top_user.instance_exec do
            next_state_sig <= this.end_state_value
        end
    end
    return st
end

#swait(cond) ⇒ Object

Wait a given condition.



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# File 'lib/HDLRuby/std/sequencer.rb', line 214

def swait(cond)
    return self.swhile(~cond)
end

#swhile(cond, &ruby_block) ⇒ Object

Create a sequential while statement on +cond+.



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# File 'lib/HDLRuby/std/sequencer.rb', line 219

def swhile(cond,&ruby_block)
    # Ensures there is a ruby block. This allows to use empty while
    # statement.
    ruby_block = proc { } unless ruby_block
    # Mark a step.
    st = self.step

    # Tell we are building a while and remember the state number.
    @status.last[:loop] = st.value + 1

    # Create a state to be executed if the condition is met.
    @status.push({})
    # Build the loop sub sequence.
    yes_name = HDLRuby.uniq_name("yes")
    yes_blk = HDLRuby::High::Block.new(:seq,&ruby_block)
    @status.pop

    this = self
    yes = @fsm.state(yes_name) { this.fill_top_user(yes_blk) }
    # Add a goto to the previous state.
    st.gotos << proc do
        HDLRuby::High.top_user.instance_exec do
            if cond then
                # There is a condition, it is a real while loop.
                hif(cond) { next_state_sig <= st.value + 1 }
                helse { next_state_sig <= yes.value + 1 }
                # puts("Here st: st.value+1=#{st.value+1} yes.value+1=#{yes.value+1}\n")
            else
                # There is no ending condition, this is an infinite loop.
                next_state_sig <= st.value + 1
                # puts("There st: st.value+1=#{st.value+1}\n")
            end
        end
    end
    # And to the yes state.
    yes.gotos << proc do
        HDLRuby::High.top_user.instance_exec do
            if cond then
                # There is a condition, it is a real while loop
                hif(cond) { next_state_sig <= st.value + 1 }
                helse { next_state_sig <= yes.value + 1 }
                # puts("Here yes: st.value+1=#{st.value+1} yes.value+1=#{yes.value+1}\n")
            else
                # There is no ending condition, this is an infinite loop.
                next_state_sig <= st.value + 1
                # puts("There yes: st.value+1=#{st.value+1}\n")
            end
        end
    end
    # puts "st_value=#{st.value} yes_value=#{yes.value}"

    # Where there any break?
    if @status.last[:sbreaks] then
        # Yes, adds them the right goto since the end of loop state
        # is now defined.
        @status.last[:sbreaks].each do |st_brk|
            st_brk.gotos << proc do
                HDLRuby::High.top_user.instance_exec do
                    next_state_sig <= yes.value + 1
                end
            end
        end
        # And remove them from the status to avoid reprocessing them,
        @status.last.clear
    end

    return st
end