Hi,
I have a Cortex-R5F core in which integration register value CPACR.ASEDIS = 1 and CPACR.D32DIS = 1m which says Advanced SIMD is not available. However, in ARM Cortex-R5F Technical Reference Manual revision r1p2, §2.1.2 "ARM architecture", it says:
The Cortex-R5 processor implements the ARMv7-R architecture profile that includes thefollowing architecture extensions:• Advanced Single Instruction Multiple Data (SIMD) architecture extension for integer andfloating-point vector operations
Who is right? Is Advanced SIMD supported or not?
Also, I am a bit confused between "Advanced SIMD" and "SIMD". Register ID_ISAR3.SIMD_instructions = 0x3, which means a bunch of SIMD instructions are enabled:
PKHBT, PKHTB, QADD16, QADD8, QASX, QSUB16, QSUB8, QSAX, SADD16, SADD8, SASX, SEL, SHADD16, SHADD8, SHASX,SHSUB16, SHSUB8, SHSAX, SSAT, SSAT16, SSUB16, SSUB8, SSAX, SXTAB16, SXTB16, UADD16, UADD8, UASX, UHADD16,UHADD8, UASX, UHSUB16, UHSUB8, USAX, UQADD16, UQADD8, UQASX, UQSUB16, UQSUB8, UQSAX, USAD8, USADA8, USAT,USAT16, USUB16, USUB8, USAX, UXTAB16, UXTB16, and the GE[3:0] bits in the PSRs.
I understand that these are like normal SIMD instructions, but that it excludes "Advanced SIMD" instructions. Am I right?
Thanks.
Hi there,
Thanks for reporting this error. You are correct that Cortex-R5 implements SIMD, but not Advanced SIMD (NEON). (Advanced SIMD is introduced in Cortex-R52, Armv8-R).
For reference, the error is in section 1.2.1, not 2.1.2 (I guess that is a typo). The same error is found in Cortex-R4 TRM.
regards,
Joseph
Indeed, §1.2.1. And thanks for the confirmation.
And by the say, there is also an unrelated error near there: §1.2.4 "Debug Architecture" says: "The Cortex-A9 processor implements...". This should of course be Cortex-R5. However, because of the error, we do not know if we can rely on the rest of the sentence (saying that Security Extensions and CoreSight are built into the core). Is it true?
Étienne
Hi Étienne,
CoreSight debug architecture is supported, but TrustZone Security Extension is not supported.
Hi, Is it possible to run Cortex-M SIMD instruction on Cortex-R to reuse the existing code from Cortex-M to Cortex-R4 after recompilation?
In general, yes. SIMD thumb2 instructions (not Advanced SIMD, aka, NEON）on Cortex-M can run on Cortex-R