Reorder

Block: Reorder (reorder)

Block Author: Aaron Parsons

Document Author: Aaron Parsons

Contents Summary Mask Parameters Ports Description

Summary

Permutes a vector of samples to into the desired order.

Mask Parameters

Parameter	Variable	Description
Output Order	map	Assuming an input order of 0, 1, 2, …, this is a vector of the desired output order (e.g. [0 1 2 3]).
No. of inputs.	n_inputs	The number of parallel streams to which this reorder should be applied.
BRAM Latency	bram_latency	The latency of the BRAM buffer.
Map Latency	map_latency	The latency allowed for the combinatorial logic required for mapping a counter to the desired output order. If your permutation can be acheived by simply reordering bits (as is the case for bit reversed order, reverse order, and matrix tranposes with power-of-2 dimensions), a map latency of 0 is appropriate. Otherwise, 1 or 2 is a good idea.
Double Buffer	double_buffer	By default, this block uses single buffering (meaning it uses a buffer only the size of the vector, and permutes the data order in place). You can override this by setting this parameter to 1, in which case 2 buffers are used to permute the vector (saving logic resources at the expense of BRAM).

Ports

Port	Dir	Data Type	Description
sync	in	Boolean	Indicates the next clock cycle contains valid data
en	in	Boolean	Indicates the current input data is valid.
din	in	Inherited	The data stream(s) to be permuted.
sync_out	out	Boolean	Indicates that data out will be valid next clock cycle.
valid	out	Boolean	Indicates the current output data is valid.
dout	out	Inherited	The permuted data stream(s).

Description

Permutes a vector of samples into the desired order. By default, this block uses a single buffer to do this. As vectors are permuted, the data placement in memory will go through several orders before it repeats. For large orders ( > 16) you should consider using double buffering, but otherwise, this block saves BRAM resources with only a modest increase in logic resources.