ZAP - Pipelined ARM Compatible core with cache and MMU

ZAP - Pipelined ARM Compatible core with cache and MMU


Category: Processor

Created: April 30, 2017

Updated: January 27, 2020

Language: Verilog

Other project properties

Development Status: Alpha

Additional info: Design done, Specification done

WishBone compliant: Yes

WishBone version: B.3

License: GPL


ZAP : ARM compatible core with cache and MMU (ARMv4T ISA compatible)

Author : Revanth Kamaraj (

License : GPL v2


ZAP is a pipelined ARM processor core that can execute the ARMv4T instruction set. It is equipped with ARMv4 compatible split writeback caches and memory management capabilities. The processor core uses a 10 stage pipeline.

Bus Interface

Wishbone B3 compatible 32-bit bus.


Please see the pdf file at doc/ZAP_PROCESSOR_CORE_DATASHEET.pdf


Fully synthesizable Verilog-2001 core.    
Store buffer for improved performance.    
Can execute ARMv4T code. Note that compressed instruction support is EXPERIMENTAL.
Wishbone B3 compatible interface. Cache unit supports burst access.
10-stage pipeline design. Pipeline has bypass network to resolve dependencies.
2 write ports for the register file to allow LDR/STR with writeback to execute as a single instruction.
Branch prediction supported.
Split I and D writeback cache (Size can be configured using parameters).
Split I and D MMUs (TLB size can be configured using parameters).
Base restored abort model to simplify data abort handling.


Copyright (C) 2016, 2017, 2018 Revanth Kamaraj.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.


- Issues with the Thumb ISA.
- SWAP does not cause cache to sync with memory.