Semiconductor & Computer Engineering
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| − | One can specify {{arm|NEON}} support using the <code>-mfpu=neon</code> option. Note that GCC will not generate floating-point operations for auto-vectorization constructs because NEON is not fully [[IEEE 754]]-compliant. It's possible to use <code>-funsafe-math-optimizations</code> to circumvent that behavior. | + | One can specify {{arm|NEON}} support using the <code>-mfpu=neon</code> option. Note that GCC will not generate floating-point operations for auto-vectorization constructs because [[NEON]], under [[ARMv7]], is not fully [[IEEE 754]]-compliant. It's possible to use <code>-funsafe-math-optimizations</code> to circumvent that behavior. |
== Architecture == | == Architecture == | ||
Revision as of 13:30, 31 December 2018
| Edit Values | |
| Cortex-A9 µarch | |
| General Info | |
| Arch Type | CPU |
| Designer | ARM Holdings |
| Manufacturer | TSMC |
| Introduction | October 3, 2007 |
| Process | 40 nm |
| Instructions | |
| ISA | ARMv7 |
| Succession | |
Cortex-A9 is the successor to the Cortex-A8, a low-power performance ARM microarchitecture designed by ARM Holdings for the mobile market. This microarchitecture is designed as a synthesizable IP core and is sold to other semiconductor companies to be implemented in their own chips.
The Cortex-A9 was later succeeded by four independent lines - high-performance (A15), mainstream performance (A12), high efficiency (A7), and ultra-low power (A5).
Compiler support
| Compiler | Arch-Specific | Arch-Favorable |
|---|---|---|
| Arm Compiler | -mcpu=cortex-a9 |
-mtune=cortex-a9
|
| GCC | -mcpu=cortex-a9 |
-mtune=cortex-a9
|
| LLVM | -mcpu=cortex-a9 |
-mtune=cortex-a9
|
One can specify NEON support using the -mfpu=neon option. Note that GCC will not generate floating-point operations for auto-vectorization constructs because NEON, under ARMv7, is not fully IEEE 754-compliant. It's possible to use -funsafe-math-optimizations to circumvent that behavior.
Architecture
Key changes from Cortex-A8
- Fully synthesizable RTL (prior designs were hand/automated layout)
- 40 nm process (from 65 nm)
- New out-of-order pipeline (form in-order)
- Shorter pipeline (9-12 stages, down from 13)
- 2x frequency (2 GHz, up from 1 GHz)
- NEON
- Added Half precision support
This list is incomplete; you can help by expanding it.
Licensees
Arm named the following companies as licensees.
| codename | Cortex-A9 + |
| designer | ARM Holdings + |
| first launched | October 3, 2007 + |
| full page name | arm holdings/microarchitectures/cortex-a9 + |
| instance of | microarchitecture + |
| instruction set architecture | ARMv7 + |
| manufacturer | TSMC + |
| microarchitecture type | CPU + |
| name | Cortex-A9 + |
| process | 40 nm (0.04 μm, 4.0e-5 mm) + |