PPC little endian?

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1

Hi,

I am wondering why we dont support PPC32 LE?

Here is the output of llvm-mc --version, in which only PPC32, PPC64 & PPC64LE are supported.

$ llvm-mc --version
LLVM (http://llvm.org/):
LLVM version 3.6.2
Optimized build with assertions.
Built Aug 2 2015 (11:39:46).
Default target: x86_64-apple-darwin15.4.0
Host CPU: core-avx2

Registered Targets:
aarch64 - AArch64 (little endian)
aarch64_be - AArch64 (big endian)
amdgcn - AMD GCN GPUs
arm - ARM
arm64 - ARM64 (little endian)
armeb - ARM (big endian)
cpp - C++ backend
hexagon - Hexagon
mips - Mips
mips64 - Mips64 [experimental]
mips64el - Mips64el [experimental]
mipsel - Mipsel
msp430 - MSP430 [experimental]
nvptx - NVIDIA PTX 32-bit
nvptx64 - NVIDIA PTX 64-bit
ppc32 - PowerPC 32
ppc64 - PowerPC 64
ppc64le - PowerPC 64 LE
r600 - AMD GPUs HD2XXX-HD6XXX
sparc - Sparc
sparcv9 - Sparc V9
systemz - SystemZ
thumb - Thumb
thumbeb - Thumb (big endian)
x86 - 32-bit X86: Pentium-Pro and above
x86-64 - 64-bit X86: EM64T and AMD64
xcore - XCore

2

Hi Jun,
There are no PowerPC 32-bit Little-Endian machines.
Little-endian was introduced with OpenPOWER a couple years ago, and a decision was made to only support 64-bit.

Kit Barton, Ph.D.
LLVM Development on POWER
IBM Toronto Lab, D2/929/8200/MKM
8200 Warden Ave, Markham, L6G 1C7
(905) 413-3452
kbarton@ca.ibm.com

3

Hi Jun,
There are no PowerPC 32-bit Little-Endian machines.
Little-endian was introduced with OpenPOWER a couple years ago, and a
decision was made to only support 64-bit.

Kit, this clears my doubt. Thank you a lot!

4

Hi Jun,
There are no PowerPC 32-bit Little-Endian machines.

This is not true

However, this feature is not available on all CPU models, and was never used widely.

Little-endian was introduced with OpenPOWER a couple years ago, and a decision was made to only support 64-bit.

This is certainly true for POWER series of CPUs, produced by IBM

5

Yes, thank you for the clarification. PowerPC has supported both modes for many generations, although I wasn’t aware off hand of documentation describing this. Thank you for sending the links.

Kit Barton, Ph.D.
LLVM Development on POWER
IBM Toronto Lab, D2/929/8200/MKM
8200 Warden Ave, Markham, L6G 1C7
(905) 413-3452
kbarton@ca.ibm.com