Module `Hardcaml.Fifo`Source

Synchronous FIFO implementions with optional showahead functionality and pipelining stages.

Sourcetype 'a t = {

q : 'a;
full : 'a;
empty : 'a;
nearly_full : 'a;
nearly_empty : 'a;
used : 'a;

}

include sig ... end

Sourceval sexp_of_t : ('a -> Sexplib0.Sexp.t) -> 'a t -> Sexplib0.Sexp.t

Sourceval iter : 'a t -> f:('a -> Base.unit) -> Base.unit

Sourceval iter2 : 'a t -> 'b t -> f:('a -> 'b -> Base.unit) -> Base.unit

Sourceval map : 'a t -> f:('a -> 'b) -> 'b t

Sourceval map2 : 'a t -> 'b t -> f:('a -> 'b -> 'c) -> 'c t

Sourceval to_list : 'a t -> 'a Base.list

Sourceval port_names_and_widths : (Base.string * Base.int) t

Sourceval equal : ('a -> 'a -> bool) -> 'a t -> 'a t -> bool

Sourceval port_names : Base.string t

Sourceval port_widths : Base.int t

Sourceval const : 'a -> 'a t

Sourcetype tag

Sourceval tags : tag t

Sourceval to_alist : 'a t -> (tag * 'a) Base.list

Sourceval of_alist : (tag * 'a) Base.list -> 'a t

Sourceval sum_of_port_widths : Base.int

Sourcemodule Unsafe_assoc_by_port_name : sig ... end

Sourceval zip : 'a t -> 'b t -> ('a * 'b) t

Sourceval zip3 : 'a t -> 'b t -> 'c t -> ('a * 'b * 'c) t

Sourceval zip4 : 'a t -> 'b t -> 'c t -> 'd t -> ('a * 'b * 'c * 'd) t

Sourceval zip5 : 'a t -> 'b t -> 'c t -> 'd t -> 'e t -> ('a * 'b * 'c * 'd * 'e) t

Sourceval map3 : 'a t -> 'b t -> 'c t -> f:('a -> 'b -> 'c -> 'd) -> 'd t

Source

val map4 : 
  'a t ->
  'b t ->
  'c t ->
  'd t ->
  f:('a -> 'b -> 'c -> 'd -> 'e) ->
  'e t

Source

val map5 : 
  'a t ->
  'b t ->
  'c t ->
  'd t ->
  'e t ->
  f:('a -> 'b -> 'c -> 'd -> 'e -> 'f) ->
  'f t

Source

val iter3 : 
  'a t ->
  'b t ->
  'c t ->
  f:('a -> 'b -> 'c -> Base.unit) ->
  Base.unit

Source

val iter4 : 
  'a t ->
  'b t ->
  'c t ->
  'd t ->
  f:('a -> 'b -> 'c -> 'd -> Base.unit) ->
  Base.unit

Source

val iter5 : 
  'a t ->
  'b t ->
  'c t ->
  'd t ->
  'e t ->
  f:('a -> 'b -> 'c -> 'd -> 'e -> Base.unit) ->
  Base.unit

Sourceval fold : 'a t -> init:'acc -> f:('acc -> 'a -> 'acc) -> 'acc

Sourceval fold2 : 'a t -> 'b t -> init:'acc -> f:('acc -> 'a -> 'b -> 'acc) -> 'acc

Sourceval scan : 'a t -> init:'acc -> f:('acc -> 'a -> 'acc * 'b) -> 'b t

Source

val scan2 : 
  'a t ->
  'b t ->
  init:'acc ->
  f:('acc -> 'a -> 'b -> 'acc * 'c) ->
  'c t

Sourceval offsets : ?rev:Base.bool -> Base.unit -> Base.int t

Sourceval of_interface_list : 'a t Base.list -> 'a Base.list t

Sourceval to_interface_list : 'a Base.list t -> 'a t Base.list

Sourcemodule All (M : Base.Monad.S) : sig ... end

Sourceval or_error_all : 'a Base.Or_error.t t -> 'a t Base.Or_error.t

Sourcemodule type Comb = sig ... end

Sourcemodule Make_comb (Comb : Comb.S) : sig ... end

Sourcemodule Of_bits : sig ... end

Sourcemodule Of_signal : sig ... end

Sourcemodule Of_always : sig ... end

Sourcemodule Names_and_widths : sig ... end

Source

type 'a create_params =
  ?nearly_empty:Base.int ->
  ?nearly_full:Base.int ->
  ?overflow_check:Base.bool ->
  ?reset:Signal.t ->
  ?underflow_check:Base.bool ->
  ?ram_attributes:Rtl_attribute.t Base.list ->
  ?scope:Scope.t ->
  'a

Source

type create_fifo =
  (Base.unit ->
    capacity:Base.int ->
    clock:Signal.t ->
    clear:Signal.t ->
    wr:Signal.t ->
    d:Signal.t ->
    rd:Signal.t ->
    Signal.t t)
    create_params

Sourcemodule Kinded_fifo : sig ... end

Base RTL FIFO

Source

val create : 
  ?showahead:Base.bool ->
  ?nearly_empty:Base.int ->
  ?nearly_full:Base.int ->
  ?overflow_check:Base.bool ->
  ?reset:Signal.t ->
  ?underflow_check:Base.bool ->
  ?ram_attributes:Rtl_attribute.t Base.list ->
  ?scope:Scope.t ->
  Base.unit ->
  capacity:Base.int ->
  clock:Signal.t ->
  clear:Signal.t ->
  wr:Signal.t ->
  d:Signal.t ->
  rd:Signal.t ->
  Signal.t Hardcaml__.Fifo_intf.T.t

create ~clock ~clear ~wr ~d ~rd capacity builds a FIFO with capacity elements which is written with d when wr is high and read when rd is high.

The default reset configuration is to use a synchronous clr signal. An asynchronous rst may be optionally provided. One of clr or rst must be non-empty.

Optional overflow and underflow checking may be used. Data will not be written(/read) when the fifo is full(/empty) regardles or the wr/(rd) signals.

nearly_emtpy and nearly_full may be programmed to go high when the fifo is nearing an underflow or overflow state.

The showahead mode changes the read behaviour of the FIFO. When showahead is false read data is available 1 cycle after rd is high. With showahead true the data is available when the fifo is not empty (you can also think of this as data being available on the same cycle that rd is asserted). To support showahead behaviour the timing of the full/empty flag changes (although they still correctly indicate when it is safe to read or write to the FIFO). showahead mode has some extra cost in terms of extra logic. The implementation ensures the output is registered and timing performance is good - nearly as fast as the underlying RAM allows.

Note; showahead is sometimes referred to as "first word fall through". It uses the write-before-read ram mode which is problematic in synthesis so we include special logic that performs collision detection.

The used output indicates the number of elements currently in the FIFO.

Functions to derive fifo architectures from other architecetures.

Source

val showahead_fifo_of_classic_fifo : 
  Kinded_fifo.create_classic ->
  Kinded_fifo.create_showahead Base.Staged.t

Derived FIFO architectures.

Source

val create_classic_with_extra_reg : 
  ?nearly_empty:Base.int ->
  ?nearly_full:Base.int ->
  ?overflow_check:Base.bool ->
  ?reset:Signal.t ->
  ?underflow_check:Base.bool ->
  ?ram_attributes:Rtl_attribute.t Base.list ->
  ?scope:Scope.t ->
  Base.unit ->
  capacity:Base.int ->
  clock:Signal.t ->
  clear:Signal.t ->
  wr:Signal.t ->
  d:Signal.t ->
  rd:Signal.t ->
  Signal.t Hardcaml__.Fifo_intf.T.t

Adds an extra output register to the non-showahead fifo. This delays the output, but ensures there is no logic data on the fifo output. Adds an extra cycle of latency (2 cycles from write to empty low).

Sourceval create_showahead_from_classic : create_fifo

Constructs a showahead fifo from a non-showahead fifo. Only modifies the control flags. Has 2 cycles of latency.

Sourceval create_showahead_with_extra_reg : create_fifo

Constructs a fifo similarly to create_showahead_from_classic and ensures the output data is registered. Has 3 cycles of latency, but is slightly faster than create ~showahead:true - it seems to only be limited by the underlying RAM frequency.

Sourcemodule type Config = sig ... end

Sourcemodule With_interface (Config : Config) : sig ... end

Create FIFO using interfaces.

package hardcaml

Module Hardcaml.FifoSource

Base RTL FIFO

Functions to derive fifo architectures from other architecetures.

Derived FIFO architectures.

Module `Hardcaml.Fifo`Source