Save registers

Author: InversionSpaces

src/X86_64.lama

@@ -6,6 +6,7 @@ import List;
 import Buffer;
 import Fun;
 import Manifest;
+import Array;
 
 -- Assembler language interface
 -- The registers:
@@ -419,6 +420,17 @@ fun compileBinOp (op, lhs, rhs, res) {
   esac
 }
 
+fun regsSaved (call) {
+  let saved = [rcx, rdx, rsi, rdi, r8, r9, r10, r11] in
+  foldlArray(
+    fun (c, r) { 
+      singletonBuffer(Push(r)) <+> c <+ Pop(r) 
+    },
+    singletonBuffer(call),
+    saved
+  )
+}
+
 -- Compiles stack machine code into a list of x86 instructions. Takes an environment
 -- and stack machine code, returns an updated environment and x86 code.
 fun compile (env, code) {
@@ -429,15 +441,15 @@ fun compile (env, code) {
       case i of
         READ ->
           case env.allocate of
-            [s, env] -> [env, code <+
-                Push (rcx) <+ -- Read clobbers rcx
-                Call ("Lread") <+
-                Pop (rcx) <+ -- Restore rcx
+            [s, env] -> [env, code <+>
+                regsSaved(Call ("Lread")) <+
                 Mov (rax, s)]
           esac             
       | WRITE ->
           case env.pop of
-            [s, env] -> [env, code <+ Mov (s, rdi) <+ Call ("Lwrite")]
+            [s, env] -> [env, code <+ 
+              Mov (s, rdi) <+> 
+              regsSaved(Call ("Lwrite"))]
           esac
       | ST (x) -> let env = env.addGlobal(x) in [env, code <+> move (env.peek, env.loc(x))]
       | LD (x) -> let [l, env] = env.addGlobal(x).allocate in [env, code <+> move (env.loc(x), l)]