ARM Cortex-A76

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ARM Cortex-A76
Produced2018[1]
Designed byARM Holdings
Max. CPU clock rateto 3.0 GHz in phones and 3.3 GHz in tablets/laptops 
MicroarchitectureARMv8.2-A
Cores1–4 Cortex-A76 cores per cluster, with additional Cortex-A55 cores to make 8 cores maximum, multiple clusters
L1 cache128 KB (64 KB I-cache with parity, 64 KB D-cache) per core
L2 cache256–512 KB
L3 cache1–4 MB
PredecessorARM Cortex-A75
ARM Cortex-A73
ARM Cortex-A72
SuccessorARM Cortex-A77
Product code name(s)
  • Enyo

The ARM Cortex-A76 is a microarchitecture implementing the ARMv8.2-A 64-bit instruction set designed by ARM Holdings' Austin design centre.[2] The Cortex-A76 frontend is a 4-wide decode out-of-order superscalar design. The backend is 8 execution ports with a pipeline depth of 13 stages and the execution latencies of 11 stages.[2]

Design[edit]

The Cortex-A76 serves as the successor of the Cortex-A73 and Cortex-A75, though based on a clean sheet design. The core supports unprivileged 32-bit applications, but privileged applications must utilize the 64-bit ARMv8-A ISA.[3] It also supports Load acquire (LDAPR) instructions (ARMv8.3-A), Dot Product instructions (ARMv8.4-A), PSTATE Speculative Store Bypass Safe (SSBS) bit and the speculation barriers (CSDB, SSBB, PSSBB) instructions (ARMv8.5-A).[4]

ARM announced 25% and 35% increases in integer and floating point performance, respectively. Memory bandwidth increased 90% relative to the A75.[5][6] According to ARM, the A76 is expected to offer twice the performance of an A73 and is targeted beyond mobile workloads. The performance is targeted at "laptop class", including Windows 10 devices,[7] competitive with Intel's Kaby Lake.[8]

The Cortex-A76 support ARM's DynamIQ technology, expected to be used as high-performance cores when used in combination with Cortex-A55 power-efficient cores.[2]

Licensing[edit]

The Cortex-A76 is available as SIP core to licensees, and its design makes it suitable for integration with other SIP cores (e.g. GPU, display controller, DSP, image processor, etc.) into one die constituting a system on a chip (SoC).

ARM has also collaborated with Qualcomm for a semi-custom version of the Cortex-A76, used within their high-end Kryo 495 (Snapdragon 8cx)/Kryo 485 (Snapdragon 855) and mid-range Kryo 460 (Snapdragon 675) CPUs. One of the modifications Qualcomm made was increasing reorder buffer to increase the out-of-order window size.[9]

References[edit]

  1. ^ Shrout, Ryan; Moorhead, Patrick (31 May 2018). "Ep 23 - 5/31/18 - The Future of Arm with Nandan Nayampally". The Tech Analysts Podcast. Retrieved 1 June 2018.
  2. ^ a b c Frumusanu, Andrei (31 May 2018). "ARM Cortex-A76 CPU Unveiled". Anandtech. Retrieved 1 June 2018.
  3. ^ Williams, Chris (31 May 2018). "Arm emits Cortex-A76 – its first 64-bit-only CPU core (in kernel mode)". The Register. Retrieved 1 June 2018.
  4. ^ "ARM documentation set for Cortex-A76". infocenter.arm.com. Retrieved 2019-06-15.
  5. ^ Armasu, Lucian (31 May 2018). "Arm's Cortex-A76 Could Be The First True Challenger To x86 Chips On Laptops". Tom's Hardware. Retrieved 1 June 2018.
  6. ^ Triggs, Robert (31 May 2018). "Arm Cortex-A76 CPU deep dive". Android Authority. Retrieved 1 June 2018.
  7. ^ Hruska, Joel (31 May 2018). "ARM's New Cortex-A76 SoC Targets Windows Laptop Market". Extreme Tech. Retrieved 1 June 2018.
  8. ^ Bright, Peter (1 June 2018). "ARM promises laptop-level performance in 2019". Ars Technica. Retrieved 1 June 2018.
  9. ^ Frumusanu, Andrei. "Arm's New Cortex-A77 CPU Micro-architecture: Evolving Performance". www.anandtech.com. Retrieved 2019-06-16.