I have worked with various ARM cores and because this is my first time working with the A9, I am curious how it compares to the A7 and A8 cores I have worked with.
Never mind the A53 which is a 64 bit ARMv8-A core.
The cores on my chip run at 667 Mhz.
BBB has a Cortex A8 Allwinner H3 has a Cortex A7 Zynq has a Cortex A9These are all 32 bit, ARMv7-A cores.
The A7 and A9 are very similar. I see in one table that the A9 claims 2.5 Dmips/Mhz while the A7 claims 1.9 Dmips/Mhz, so the A9 should run significantly faster at the same clock speed. Both have an 8 stage pipeline, but the A9 supports out of order execution
The Zynq 7000 series Xilinx chips are based on a 28nm process. In particular the ARM on these Zynq-7000 chips are "ARM Cortex-A9 MPCore", and were introduced in 2011.
Cortex-A9 and Cortex-A7 are almost the same. Both are Armv7-A processors. Because Cortex-A7 is the successor of the Cortex-A9, its power efficiency became increased and has some extentions such as hardware division instruction and Large Physical Address Extensions (LPAE).I was surprised to learn that only the A7 has a hardware divide instruction. It is missing on the A9 and A8.
(You can read the ID_ISAR0 register to find out if your hardware has the instruction, people have done this and verified its absence on the Zynq).
Here is a nice article on the divide instruction:
Tom's Computer Info / tom@mmto.org