On Wednesday, 28 November 2018 at 18:56:14 UTC, realhet wrote:
1. Is there register parameters? (I think no)
Of course, e.g., POD structs of power-of-2 sizes <= 8 bytes and
integral scalars as well as float/double/vectors. The stack isn't
used at all, aggregates > 8 bytes are passed by ref (caller makes
a copy on its stack and passes a pointer to it to the callee);
that seems not to be mentioned at all in the Wiki article.
2. What are the volatile regs? RAX, RCX, RDX, XMM6..XMM15?
See Microsoft's docs.
3. Is the stack pointer aligned to 16?
It is IIRC.
4. Is there a 32 byte shadow area on the stack?
Yes, IIRC.
---
LDC conforms to the regular Win64 ABI (incl. __vectorcall
extension for vectors). The biggest difference is that
`extern(D)` (as opposed to `extern(C)` or `extern(C++)`) reverses
the arguments - `foo(1, 2, 3, 4)` becomes `foo(4, 3, 2, 1)`, so
not the first 4 args are passed in registers if possible, but the
last ones (incl. special cases wrt. struct-return + `this`
pointers). Other than that, there are just very few special cases
for delegates and dynamic arrays, which only apply to `extern(D)`.
