From 96bfd3352548e1fcfda671fa101baf0c65c6d1c9 Mon Sep 17 00:00:00 2001
From: Jan Bujak <jan@parity.io>
Date: Thu, 16 Jan 2025 05:49:26 +0000
Subject: [PATCH] polkavm-assembler: add `xchg_mem`

---
 crates/polkavm-assembler/src/amd64.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/crates/polkavm-assembler/src/amd64.rs b/crates/polkavm-assembler/src/amd64.rs
index 1b406526..5b0cda58 100644
--- a/crates/polkavm-assembler/src/amd64.rs
+++ b/crates/polkavm-assembler/src/amd64.rs
@@ -1419,6 +1419,12 @@ pub mod inst {
             None,
             (fmt.write_fmt(core::format_args!("cmov{} {}, {}", self.0.suffix(), self.2.name_from(self.1), self.3.display_without_prefix(Size::from(self.1))))),
 
+        // https://www.felixcloutier.com/x86/xchg
+        xchg_mem(RegSize, Reg, MemOp) =>
+            Inst::new(0x87).rex_64b_if(matches!(self.0, RegSize::R64)).modrm_reg(self.1).mem(self.2).encode(),
+            None,
+            (fmt.write_fmt(core::format_args!("xchg {}, {}", self.1.name_from(self.0), self.2))),
+
         // https://www.felixcloutier.com/x86/add
         add(Operands) =>
             alu_impl(0x00, 0x02, 0b000, self.0),
@@ -2384,6 +2390,7 @@ mod tests {
         syscall,
         test,
         ud2,
+        xchg_mem,
         xor,
     }