Add tracking issue and unstable book page for `"vectorcall"` ABI

1 files changed, 19 insertions, 0 deletions

diff --git a/src/doc/unstable-book/src/language-features/abi-vectorcall.md b/src/doc/unstable-book/src/language-features/abi-vectorcall.md
new file mode 100644
index 00000000000..56273bfdb79
--- /dev/null
+++ b/src/doc/unstable-book/src/language-features/abi-vectorcall.md
@@ -0,0 +1,19 @@
+# `abi_vectorcall`
+
+The tracking issue for this feature is: [#124485]
+
+[#124485]: https://github.com/rust-lang/rust/issues/124485
+
+------------------------
+
+Adds support for the Windows `"vectorcall"` ABI, the equivalent of `__vectorcall` in MSVC.
+
+```rust,ignore (only-windows-or-x86-or-x86-64)
+extern "vectorcall" {
+    fn add_f64s(x: f64, y: f64) -> f64;
+}
+
+fn main() {
+    println!("{}", add_f64s(2.0, 4.0));
+}
+```