Multi-queue FIFO memory devices that support flow-through of write and read counter updates using multi-port flag counter register files
View Patent ↗Multi-queue first-in first-out (FIFO) memory devices include multi-port register files that provide write count and read count flow-through when the write and read queues are equivalent. According to some of these embodiments, a multi-queue FIFO memory device includes a write flag counter register file that is configured to support flow-through of write counter updates to at least one read port of the write flag counter register file. This flow-through occurs when an active write queue and an active read queue within the FIFO memory device are the same. A read flag counter register file is also provided, which supports flow-through of read counter updates to at least one read port of the read flag counter register file when the active write queue and the active read queue are the same.
1. An integrated circuit chip, comprising:
a multi-queue first-in first-out (FIFO) memory device having a write flag counter register file therein that is configured to support flow-through of write counter updates to at least first, second, third and fourth read ports of the write flag counter register file when an active write queue and an active read queue within said FIFO memory device are the same, said multi-queue FIFO memory device further comprising:
a first write count generator having a first input electrically connected to the first read port, said first write count generator configured to generate at least one flag associated with the active write queue; and
a second write count generator having second, third and fourth inputs electrically connected to the second, third and fourth read ports, respectively, said second write count generator configured to generate at least one flag associated with the active read queue; and
wherein said write flag counter register file is configured to update the first read port associated with the active write queue and the second read port associated with the active read queue with an equivalent write count value during an operation to switch a write queue of said multi-queue FIFO memory device to an equivalent read queue of said multi-queue FIFO memory device; and
wherein said write flag register file is further configured to sequentially update the second, third and fourth ports with respective write count values during the operation to switch the write queue of said multi-queue FIFO memory device to the equivalent read queue of said multi-queue FIFO memory device.
2. The integrated circuit chip of claim 1 , wherein said multi-queue FIFO memory device further comprises a read flag counter register file that is configured to support flow-through of read counter updates to at least one read port of the read flag counter register file when the active write queue and the active read queue are the same.
3. The integrated circuit chip of claim 1 , wherein said second write count generator comprises:
a first multiplexer having first and second inputs electrically coupled to the second and third read ports of the write flag counter register file; and
a second multiplexer having first and second inputs electrically coupled to the third and fourth read ports of the write flag counter register file.
4. The integrated circuit chip of claim 1 , wherein said first write count generator is configured to generate a write count value associated with a full flag calculation and a write count value associated with a programmable almost full flag calculation.
5. The integrated circuit chip of claim 4 , wherein said second write count generator is configured to generate a write count value associated with an empty flag calculation and a write count value associated with a programmable almost empty flag calculation.
6. A multi-queue FIFO memory device, comprising:
a write flag counter register file having first, second, third and fourth multi-bit read ports;
a first write count generator configured to generate two flags associated with an active write queue, in response to a first count value generated at the first multi-bit read port of said write flag counter register file; and
a second write count generator configured to generate two flags associated with an active read queue, in response to second, third and fourth count values generated at the second, third and fourth multi-bit read ports of said write flag counter register file, respectively;
wherein said write flag counter register file is configured to capture the first and second count values as equivalent values at the first and second multi-bit read ports, respectively, during an equivalent cycle of a write queue switch operation; and
wherein said write flag counter register file is configured to sequentially capture the second, third and fourth count values at the second, third and fourth multi-bit read ports, respectively, during different cycles of the write queue switch operation.
7. The multi-queue FIFO memory device of claim 6 , wherein said second write count generator comprises:
a first multiplexer device having first and second inputs electrically coupled to the second and third multi-bit read ports of said write flag counter register file, respectively; and
a second multiplexer device having first and second inputs electrically coupled to the third and fourth multi-bit read ports of said write flag counter register file, respectively.