Add pi400 (#260)

* Add Pi400 detection

Maybe Pi4 with 8GB of memory is not listed yet, need to find the board revision to improve even better.

* Pi400 update

Matching with CMakeLists.txt

Author: dglaude

CMakeLists.txt

@@ -33,8 +33,8 @@ if (BOARD_REVISION MATCHES "(0002)|(0003)|(0004)|(0005)|(0006)|(0007)|(0008)|(00
 elseif(BOARD_REVISION MATCHES "(a01041)|(a21041)")
 	message(STATUS "Detected this board to be a Pi 2 Model B < rev 1.2 with ARMv7-A instruction set CPU.")
 	set(DEFAULT_TO_ARMV7A ON)
-elseif(BOARD_REVISION MATCHES "(a02082)|(a22082)|(a020d3)|(9020e0)|(a03111)|(b03111)|(b03140)|(c03111)")
-	message(STATUS "Detected this Pi to be one of: Pi 2B rev. 1.2, 3B, 3B+, 3A+, CM3, CM3 lite, CM4 or 4B(1GB,2GB,4GB RAM), with 4 hardware cores and ARMv8-A instruction set CPU.")
+elseif(BOARD_REVISION MATCHES "(a02082)|(a22082)|(a020d3)|(9020e0)|(a03111)|(b03111)|(b03140)|(c03111)|(c03130)")
+	message(STATUS "Detected this Pi to be one of: Pi 2B rev. 1.2, 3B, 3B+, 3A+, CM3, CM3 lite, CM4, 4B(1GB,2GB,4GB RAM) or Pi400, with 4 hardware cores and ARMv8-A instruction set CPU.")
 	set(DEFAULT_TO_ARMV8A ON)
 else()
 	message(WARNING "The board revision of this hardware is not known. Please add detection to this board in CMakeLists.txt. (proceeding to compile against a generic multicore CPU)")

README.md

@@ -159,7 +159,7 @@ There are a couple of options to explicitly say which Pi board you want to targe
 - `-DSINGLE_CORE_BOARD=ON`: Pass this option if you are running on a Pi that has only one hardware thread (Pi Model A, Pi Model B, Compute Module 1, Pi Zero/Zero W). If not present, autodetected.
 - `-DARMV6Z=ON`: Pass this option to specifically optimize for ARMv6Z instruction set (Pi 1A, 1A+, 1B, 1B+, Zero, Zero W). If not present, autodetected.
 - `-DARMV7A=ON`: Pass this option to specifically optimize for ARMv7-A instruction set (Pi 2B < rev 1.2). If not present, autodetected.
-- `-DARMV8A=ON`: Pass this option to specifically optimize for ARMv8-A instruction set (Pi 2B >= rev. 1.2, 3B, 3B+, CM3, CM3 lite or 4B). If not present, autodetected.
+- `-DARMV8A=ON`: Pass this option to specifically optimize for ARMv8-A instruction set (Pi 2B >= rev. 1.2, 3B, 3B+, CM3, CM3 lite, 4B, CM4, Pi400). If not present, autodetected.
 
 ###### Specifying other build options