This is the mail archive of the
mailing list for the GCC project.
Re: modified x86 ABI
Andreas Jaeger wrote:
One interesting question to me is what is the ABI like compared to the
x86-64 ABI? Did you just change the size of the types or did you change
others as well, e.g. calling conventions?
The ABI we used is based on the standard x86-64 ABI. The ILP32 objects
adopt the following conventions:
- 16-byte alignment of the stack pointer upon calls.
- Arguments <= 32 bits wide for a call are padded to 32 bits and then
aligned on 32-bit boundaries on the stack. Any padding is above the
- 64-bit arguments are aligned on 64-bit boundaries -- which may mean
that padding is inserted beneath them (for example if there is a
32-bit argument aligned to a 64-bit boundary beneath the 64-bit
argument). No more padding than is required is inserted.
- 128-bit arguments are aligned on a 128-bit boundary.
In all other respects the ABI follows the x86-64 one. The ILP32 objects
Do you need new binutils for this? A new C library?
Our binutils changes were minor, and a new C library will be required.