SONAME and powerpc64le-linux ABI changes

Joseph Myers
Wed Oct 6 22:03:59 GMT 2021

On Wed, 6 Oct 2021, Segher Boessenkool wrote:

> With "not in any" I mean: not for other architectures either!  All archs
> that do not say anything about floating point in their machine
> description get a working sofware floating point (for binary32 and
> binary64 currently).

Any architecture that supports a software floating-point ABI (i.e. one 
that does argument passing and return for floating-point in integer 
registers) should specify it in its ABI documents.  For example, 
describes both "Integer Calling Convention" and "Hardware Floating-point 
Calling Convention", with a series of named ABIs based on those such as 
LP64, LP64F, etc. (like on (32-bit) Arm, but unlike Power or MIPS, RISC-V 
GCC also supports building programs that use hardware floating-point 
instructions but the software floating-point ABI).

That's how the (unified) 32-bit powerpc ABI documents things: both 
hardware and software floating-point ABI variants.

If the architecture doesn't support hardware floating point, or doesn't 
have separate registers for it, the software floating-point ABI is just 
"the ABI" and there's no separate hardware floating-point ABI, of course.

Joseph S. Myers

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