work

src/arch/x86_64/mod.rs

@@ -28,7 +28,27 @@ impl Arch for X86_64 {
     }
 }
 
-pub struct CallConv {
-    volatile: Vec<Reg>,
-    nonvolatile: Vec<Reg>,
+pub enum CallConv {
+    SystemV,
+}
+
+impl CallConv {
+    pub fn param(&self) -> &[Reg] {
+        use regs::*;
+        match self {
+            Self::SystemV => &[rdi, rsi, rdx, rcx, r8, r9],
+        }
+    }
+    pub fn scratch(&self) -> &[Reg] {
+        use regs::*;
+        match self {
+            Self::SystemV => &[rax, rdi, rsi, rdx, rcx, r8, r9, r10, r11],
+        }
+    }
+    pub fn ret(&self) -> &[Reg] {
+        use regs::*;
+        match self {
+            Self::SystemV => &[rax, rdx],
+        }
+    }
 }