doc: Add multilib section to CPU supplement

Add multilib section for ARM and PowerPC

1 files changed, 57 insertions, 0 deletions

diff --git a/doc/cpu_supplement/arm.t b/doc/cpu_supplement/arm.t
index 5dacbc0e73..012728cdb0 100644
--- a/doc/cpu_supplement/arm.t
+++ b/doc/cpu_supplement/arm.t
@@ -52,6 +52,63 @@ The following floating point units are supported.
 
 @end itemize
 
+@c
+@c
+@c
+@section Multilibs
+
+The following multilibs are available:
+
+@enumerate
+@item @code{.}: ARMv4T, ARM instruction set
+@item @code{thumb}: ARMv4T, Thumb-1 instruction set
+@item @code{thumb/armv6-m}: ARMv6M, subset of Thumb-2 instruction set
+@item @code{thumb/armv7-a}: ARMv7-A, Thumb-2 instruction set
+@item @code{thumb/armv7-a/neon/hard}: ARMv7-A, Thumb-2 instruction set with
+hard-float ABI Neon and VFP-D32 support
+@item @code{thumb/armv7-r}: ARMv7-R, Thumb-2 instruction set
+@item @code{thumb/armv7-r/vfpv3-d16/hard}: ARMv7-R, Thumb-2 instruction set
+with hard-float ABI VFP-D16 support
+@item @code{thumb/armv7-m}: ARMv7-M, Thumb-2 instruction set with hardware
+integer division (SDIV/UDIV)
+@item @code{thumb/armv7-m/fpv4-sp-d16}: ARMv7-M, Thumb-2 instruction set with
+hardware integer division (SDIV/UDIV) and hard-float ABI FPv4-SP support
+@item @code{eb/thumb/armv7-r}: ARMv7-R, Big-endian Thumb-2 instruction set
+@item @code{eb/thumb/armv7-r/vfpv3-d16/hard}: ARMv7-R, Big-endian Thumb-2
+instruction set with hard-float ABI VFP-D16 support
+@end enumerate
+
+Multilib 1. and 2. support the standard ARM7TDMI and ARM926EJ-S targets.
+
+Multilib 3. supports the Cortex-M0 and Cortex-M1 cores.
+
+Multilib 8. supports the Cortex-M3 and Cortex-M4 cores, which have a special
+hardware integer division instruction (this is not present in the A and R
+profiles).
+
+Multilib 9. supports the Cortex-M4 cores with a floating point unit.
+
+Multilib 4. and 5. support the Cortex-A processors.
+
+Multilib 6., 7., 10. and 11. support the Cortex-R processors.  Here also
+big-endian variants are available.
+
+Use for example the following GCC options
+
+@example
+-mthumb -march=armv7-a -mfpu=neon -mfloat-abi=hard -mtune=cortex-a9
+@end example
+
+to build an application or BSP for the ARMv7-A architecture and tune the code
+for a Cortex-A9 processor.  It is important to select the options used for the
+multilibs. For example
+
+@example
+-mthumb -mcpu=cortex-a9
+@end example
+
+alone will not select the ARMv7-A multilib.
+
 @section Calling Conventions
 
 Please refer to the