AndesCore™ A45MP Multicore

32-bit Multiprocessors with Level-2 Cache-Coherence

AndesCore™ A45MP Overview

  • 32-bit, 8-stage in-order superscalar pipeline CPU architecture
  • Symmetric multiprocessing up to 4 cores
  • Level-2 cache and cache coherence support
  • AndeStar™ V5 Instruction Set Architecture (ISA). Compliant to RISC-V ISA IMACFDN, with Andes performance/functionality extensions
  • Floating point extensions
  • DSP/SIMD ISA to boost the performance of voice, audio, image and signal processing
  • Separately licensable Andes Custom Extension™ (ACE) for customized acceleration
  • 16/32-bit mixable instruction format for compacting code density
  • Branch prediction to speed up control code
  • Return Address Stack (RAS) to speed up procedure returns
  • Memory Management Unit (MMU), Physical Memory Protection (PMP) and Programmable Physical Memory Attributes (PMA)
  • Level-1 and level-2 cache controllers with 64-byte cache line size
  • MemBoost for heavy memory transactions
  • Flexibly configurable Platform-Level Interrupt Controller (PLIC) for supporting wide range of system event scenarios
  • Enhancement of vectored interrupt handling for real-time performance
  • Advanced CoDense™ technology to reduce program code size

The 32-bit A45MP is an 8-stage superscalar processor that supports RISC-V specification, including “G” (“IMAFD”) standard instructions, “C” 16-bit compression instructions, “P” Packed-SIMD/DSP instructions, “N” for user-level interrupts, Memory Management Unit (MMU) for Linux support, and Andes performance/functionality enhancements for faster memory accesses and branch handling, plus Andes Custom Extension™ (ACE) to add user defined instructions.

The A45MP symmetric multiprocessor supports up to 4 cores and a level-2 cache controller with instruction and data prefetch. It manages level-2 cache coherence including I/O coherence for cacheless bus masters.

Other A45MP features include ECC for level-1/2 memory soft error protection, PLIC with enhancements for vectored dispatch and priority-based preemption, CoDense™, StackSafe™ for software quality improvement, and QuickNap™, PowerBrake, and WFI for power management.


  • High performance application processor
  • AI, Machine Learning, Deep Learning
  • Video and Image Processing

Block Diagram

Development Tools

  • AndeSight™ IDE (Eclipse-based)
    • Compiler, Debugger, Profiler, Register Bit-field Display/Update, RTOS Awareness, and more
    • Tested platforms: Windows and Linux, single- or multi-user installation
  • Andes BSP
    • Optimized DSP library
    • Demo examples and sample projects
  • RTOSes
    • Open-source: FreeRTOS, Zephyr, RT-Thread
    • Commercial: ThreadX, μC/OS-II
  • SMP Linux kernel and platform drivers
  • COPILOT: Custom-OPtimized Instruction deveLOpment Tool for ACE
  • FPGA Development Boards
    • AndeShape™ ADP-XC7K410
    • Xilinx VCU118 and AndeShape™ FMC Modules
    • AndeShape™ Board Farm
  • Debugging Hardware

Key Features and Performance

AndeStar™ V5 Architecture

Key FeaturesBenefits
RISC-V RV64IMACFD instructions
  • State-of-the art ISA from latest developments in computer architecture
  • Industry standard and open architecture
RISC-V P-extension (draft) DSP/SIMD instructions with versatile operationsBoost the performance of voice, audio, image and signal processing
RISC-V single and double precision floating point instructionAccelerate the processing of high precision arithmetic
Andes Extended InstructionsAndes exclusive performance and functionality enhancements
RISC-V N-extension, user-level interruptSupports user-level trap handling
Andes Custom Extension™ (ACE) option to create customized instructions for software acceleration
  • Add customized instruction extensions to facilitate Domain-Specific Architecture/Acceleration (DSA)
  • Boost application performance significantly, at the same time maintain the programmability
  • Powerful constructs are available to define high level instruction
  • ACE design is based on Verilog and C languages which are familiar to the designers
  • The COPILOT tool automatically generates the extended CPU and software toolchain
  • Do not require expertise in processor pipeline to design ACE instructions
16/32-bit mixable instruction formatFor compact code density
32 general-purpose registersFor better code size and performance
Machine (M), User (U) and Supervisor (S) Privilege levelsFor Linux and advanced operating systems with protection between kernel and user programs

CPU Core

Key FeaturesBenefits
5.66 Coremark/MHz, 2.96 DMIPS/MHz*Superior performance-per-MHz
8-stage in-order superscalar pipelineSuperior performance-efficiency, while allowing for high speeds

Extensive branch predication features

  • Branch Target Buffer (BTB)
  • Branch Histroy Table (BHT)
  • Return Address Stack (RAS)
  • Branch Target Buffer and Branch History Table to speed up control codes
  • Return Address Stack to speeds up procedure returns

MMU (Memory Management Unit)

  • Sv32 virtual-memory systems
  • 4/8-entry fully associative ITLB/DTLB
  • 32-512-entry 4-way set-associative shared TLB
  • Hardware page table walker
  • Virtual memory support for full address space and easy code/data sharing
  • Support for full-featured OS such as Linux
  • Protection of supervisor and user privilege
  • Hardware for fast address translation
Physical Memory Protection (PMP), 16 regionsBasic read/write/execute memory protection with minimum cost
Programmable Physical Memory Attribute (PMA), 16 regions

Configurable memory attributes:

  • Memory, I/O, None
  • Cacheable/Non-cacheable
  • Write-back/Write-through
  • Read/write/read & write allocate, no allocate
  • Access fault for non-existent regions
Performance monitorsProgram code performance tuning
StackSafe™ hardware stack protection
  • Easy identification of stack size threshold during development
  • Hardware error detection of stack overflow and underflow at runtime

Multiplier options

  • Fast multiplier: pipelined, 2-cycle
  • Small multipliers: producing 1, 2, 4, or 8 bits per cycle
Option to choose between speed and area according to application's requirements
PowerBrake technologyPerformance throttling to digitally reduce power consumption
QuickNap™ technologyFast power-down/wake-up support for caches

* BSP v5.1.0, DMIPS/MHZ follow Dhrystone’s no-inline ground rules, best performances 

Memory Subsystems

Key FeaturesBenefits

Level-1 I-Cache & D-Cache

  • Size: 8KB to 64KB
  • Cache line size: 64 bytes
  • Set associativity: 2-way or 4-way
  • Accelerating accesses to slow memories
  • Flexible cache configurations

Level-2 I/D Unified Cache

  • Configurable from 128KB to 2MB
  • 64-byte cache line size
  • 16-way, pseudo random line replacement
  • 2 tag banks, 2 data banks with interleaving
  • Configurable memory cycles for SRAM timing
  • Accelerate performance with level-2 memory
  • Flexible selections to meet performance and timing requirements


  • Size: 4KB to 16MB
  • SRAM interface support
  • Bus masters accessed by AXI slave port
  • For deterministic and efficient program execution
  • Flexible size selection to fit diversified needs
MemBoost – Data Cache Write-AroundSmart cache line allocation policy, for better cache utilization and reduce number of memory accesses
MemBoost – Instruction and Data Pre-fetchConditionally fill instruction and data caches in advance, for minimum memory access latency
MemBoost – Multiple Outstanding Mem. Req.Issue multiple transactions to data memory sub-system for higher bus utilization, also support out-of-order completion
Optional ECC error protection with SRAM interfaceCode and data integrity protection
Bus master port: AXI with 128-bit data busHigh throughput with wide data path
BUS Slave Port: AXI with 128-bit data, for ILM/DLM accessesEfficient data transfer between CPU and SoC masters
Core/bus clock ratio of N:1Simplified SoC integration

Multicore Cache Coherence

Key FeaturesBenefits
  • Support up to 4 cores
  • MESI cache coherence protocol
  • Support I/O coherence for cacheless bus masters by 128-bit AXI slave port
  • Symmetric multicore and L2 cache controller with cache coherence between level-1 (L1) caches and I/O coherence for bus masters without caches
  • High efficient memory transaction for sophisticated Linux SMP

Platform-Level Interrupt Controller (PLIC)

Key FeaturesBenefits

Implements RISC-V PLIC specification

  • Up to 1023 PLIC interrupt sources
  • Up to 255 PLIC interrupt priority levels
  • Up to 16 PLIC interrupt targets
Allow individual interrupts to be serviced and prioritized without sharing

Enhanced interrupt features

  • Vectored interrupt dispatch
  • Priority-based preemption
  • Selectable edge trigger or level trigger
  • Faster interrupt handling for real-time applications
  • Complete hardware preemption support for faster response
  • Flexible interrupt source interface for simpler SoC design

Debug Support

Key FeaturesBenefits
Implements RISC-V debug specificationsSupported by industry debug tool suppliers
JTAG Debug PortIndustry-standard support
Embedded Debug Module with up to 8 triggersFlexible configurations to tradeoff between gate count and debugging capabilities
Exception redirection supportEntering debugger upon selected exceptions without using breakpoints

Product Package

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