ARM Cortex-A

The ARM Cortex-A is a group of 32-bit and 64-bit RISC ARM processor cores licensed by Arm Holdings. The cores are intended for application use. The group consists of 32-bit cores: ARM Cortex-A5, ARM Cortex-A7, ARM Cortex-A8, ARM Cortex-A9, ARM Cortex-A12, ARM Cortex-A15, ARM Cortex-A17 MPCore,[1] and ARM Cortex-A32,[2] and 64-bit cores: ARM Cortex-A35, ARM Cortex-A53, ARM Cortex-A55, ARM Cortex-A57, ARM Cortex-A72, ARM Cortex-A73, ARM Cortex-A75, ARM Cortex-A76 and ARM Cortex-A77.

ARM Cortex-A

General Info
Designed by	ARM Holdings
Architecture and classification
Instruction set	ARM, Thumb-2 (32-bit cores); ARMv7-A and ARMv8-A A64, A32, T32 (64-bit cores); ARMv8-A, ARMv8.1-A, ARMv8.2-A, ARM8.3-A

The 32-bit ARM Cortex-A cores, except for the Cortex-A32, implement the ARMv7-A profile of the ARMv7 architecture. The main distinguishing feature of the ARMv7-A profile, compared to the other two profiles, the ARMv7-R profile implemented by the ARM Cortex-R cores and the ARMv7-M profile implemented by most of the ARM Cortex-M cores, is that only the ARMv7-A profile includes a memory management unit (MMU).[3] Many modern operating systems require a MMU to run.

The 64-bit ARM Cortex-A cores as well as the 32-bit ARM Cortex-A32 implement the ARMv8-A profile of the ARMv8 architecture.

Overview

(32-bit)
Year	Core
2005	Cortex-A8
2007	Cortex-A9
2009	Cortex-A5
2010	Cortex-A15
2011	Cortex-A7
2013	Cortex-A12
2014	Cortex-A17
2016	Cortex-A32

(64-bit)
Year	Core
2012	Cortex-A53
2012	Cortex-A57
2015	Cortex-A35
2015	Cortex-A72
2016	Cortex-A34
2016	Cortex-A73
2017	Cortex-A55
2017	Cortex-A75
2018	Cortex-A76
2018	Cortex-A65AE
2018	Cortex-A76AE
2019	Cortex-A77

See also: ARM architecture and List of ARM cores

ARM license

ARM Holdings neither manufactures nor sells CPU devices based on its own designs, but rather licenses the processor architecture to interested parties. ARM offers a variety of licensing terms, varying in cost and deliverables. To all licensees, ARM provides an integratable hardware description of the ARM core, as well as complete software development toolset, and the right to sell manufactured silicon containing the ARM CPU.

Silicon customization

Integrated device manufacturers (IDM) receive the ARM Processor IP as synthesizable RTL (written in Verilog). In this form, they have the ability to perform architectural level optimizations and extensions. This allows the manufacturer to achieve custom design goals, such as higher clock speed, very low power consumption, instruction set extensions, optimizations for size, debug support, etc. To determine which components have been included in an ARM IC chip, consult the manufacturer datasheet and related documentation.

Instruction sets

The Cortex-A5 / A7 / A8 / A9 / A12 / A15 / A17 cores implement the ARMv7-A architecture.[1] The Cortex-A32 / A34 / A35 / A53 / A57 / A72 / A73 cores implement the ARMv8-A architecture. The Cortex-A55 / A65 / A75 / A76 / A77 cores implement the ARMv8.2-A architecture.

Documentation

The amount of documentation for all ARM chips is daunting, especially for newcomers. The documentation for microcontrollers from past decades would easily be inclusive in a single document, but as chips have evolved so has the documentation grown. The total documentation is especially hard to grasp for all ARM chips since it consists of documents from the IC manufacturer and documents from CPU core vendor (ARM Holdings).

A typical top-down documentation tree is:

1. IC Manufacturer's high-level marketing slides
2. IC Manufacturer datasheet for the exact physical chip
3. IC Manufacturer Reference Manuals — describes common peripherals and other aspects of physical chips within the same series
4. ARM Core Reference Manuals — for the exact ARM core processor within the chip
5. ARM Architecture Reference Manuals — includes detailed description of all instruction sets of the core[1]

IC Manufacturers usually have additional documents, including: evaluation board user manuals, application notes, getting started with development software, software library documents, errata, and more.

See also

• ARM architecture
• Comparison of ARMv7-A cores
• Comparison of ARMv8-A cores
• List of ARM microarchitectures and cores
• JTAG, SWD

References

1. ARMv7-A Architecture Reference Manual; ARM Holdings.
2. "ARM Cortex-A32 Specifications"
3. "Cortex-A Series".

External links

ARM Cortex-A official documents

• ARM Cortex-A official website

ARM Core	Bit Width	ARM Website	ARM Technical Reference Manual	ARM Architecture Reference Manual
Cortex-A5	32	Link	Link	ARMv7-A
Cortex-A7	32	Link	Link	ARMv7-A
Cortex-A8	32	Link	Link	ARMv7-A
Cortex-A9	32	Link	Link	ARMv7-A
Cortex-A12	32	data-sort-value="" style="vertical-align:middle; text-align:center" class="table-na" | —	data-sort-value="" style="background: #ececec; color: #2C2C2C; vertical-align: middle; text-align: center; " class="table-na" | merged into A17	ARMv7-A
Cortex-A15	32	Link	Link	ARMv7-A
Cortex-A17	32	Link	Link	ARMv7-A
Cortex-A32	32	Link	Link	ARMv8-A
Cortex-A34	64	Link	data-sort-value="" style="vertical-align:middle; text-align:center" class="table-na" | —	ARMv8-A
Cortex-A35	32/64	Link	Link	ARMv8-A
Cortex-A53	32/64	Link	Link	ARMv8-A
Cortex-A55	32/64	Link	Link	ARMv8.2-A
Cortex-A57	32/64	Link	Link	ARMv8-A
Cortex-A65	64	Link	Link	ARMv8.2-A
Cortex-A72	32/64	Link	Link	ARMv8-A
Cortex-A73	32/64	Link	Link	ARMv8-A
Cortex-A75	32/64	Link	Link	ARMv8.2-A
Cortex-A76	32/64	Link	Link	ARMv8.2-A
Cortex-A77	32/64	Link	Link	ARMv8.2-A

Quick Reference Cards

• Instructions: Thumb (1), ARM and Thumb-2 (2), Vector Floating-Point (3) – arm.com
• Opcodes: Thumb (1, 2), ARM (3, 4), GNU Assembler Directives (5).

Migrating

• Migrating from MIPS to ARM – arm.com
• Migrating from PPC to ARM – arm.com
• Migrating from SH-4 to Cortex-A – arm.com
• Migrating from IA-32 (x86-32) to ARM – arm.com