From 6e6a1a830e61e4dc20bacae42dce298654582990 Mon Sep 17 00:00:00 2001
From: nub31 <oliverlhs@outlook.com>
Date: Sun, 26 Jan 2025 20:44:22 +0100
Subject: [PATCH] Add support for stack parameters

---
 Nub.Lang/Nub.Lang/Generation/Generator.cs | 27 ++++++++++++++---------
 Nub.Lang/Nub.Lang/Input/program.nub       | 27 ++++++++++++++++++++++-
 Nub.Lang/Nub.Lang/Parsing/Parser.cs       |  1 +
 3 files changed, 43 insertions(+), 12 deletions(-)

diff --git a/Nub.Lang/Nub.Lang/Generation/Generator.cs b/Nub.Lang/Nub.Lang/Generation/Generator.cs
index e0887d5..471b797 100644
--- a/Nub.Lang/Nub.Lang/Generation/Generator.cs
+++ b/Nub.Lang/Nub.Lang/Generation/Generator.cs
@@ -109,17 +109,16 @@ public class Generator
         
         for (var i = 0; i < symbol.Parameters.Count; i++)
         {
-            var parameter = symbol.Parameters.ElementAt(i);
-
+            var parameter = symbol.ResolveLocalVariable(symbol.Parameters.ElementAt(i).Name);
             if (i < registers.Length)
             {
-                var variable = symbol.ResolveLocalVariable(parameter.Name);
-                _builder.AppendLine($"    mov [rbp - {variable.Offset}], {registers[i]}");
+                _builder.AppendLine($"    mov [rbp - {parameter.Offset}], {registers[i]}");
             }
             else
             {
-                // TODO: Implement parameters passed on the stack
-                throw new NotImplementedException();
+                var stackOffset = 16 + (i - registers.Length) * 8;
+                _builder.AppendLine($"    mov rax, [rbp + {stackOffset}]");
+                _builder.AppendLine($"    mov [rbp - {parameter.Offset}], rax");
             }
         }
         
@@ -262,24 +261,30 @@ public class Generator
         _builder.AppendLine("    call strlen");
     }
 
-    // TODO: Use stack for more than 6 parameters
     private void GenerateFuncCall(FuncCall funcCall, Func func)
     {
         var symbol = _symbolTable.ResolveFunc(funcCall.Name, funcCall.Parameters.Select(p => p.Type).ToList());
         string[] registers = ["rdi", "rsi", "rdx", "rcx", "r8", "r9"];
 
-        foreach (var parameter in funcCall.Parameters)
+        for (var i = funcCall.Parameters.Count - 1; i >= 0; i--)
         {
-            GenerateExpression(parameter, func);
+            GenerateExpression(funcCall.Parameters.ElementAt(i), func);
             _builder.AppendLine("    push rax");
         }
         
-        for (var i = funcCall.Parameters.Count - 1; i >= 0; i--)
+        var registerParameters = Math.Min(registers.Length, funcCall.Parameters.Count);
+        var stackParameters = funcCall.Parameters.Count - registerParameters;
+        
+        for (var i = 0; i < registerParameters; i++)
         {
             _builder.AppendLine($"    pop {registers[i]}");
         }
-        
+
         _builder.AppendLine($"    call {symbol.Label}");
+        if (stackParameters != 0)
+        {
+            _builder.AppendLine($"    add rsp, {stackParameters}");
+        }
     }
 
     private void GenerateSyscall(Syscall syscall, Func func)
diff --git a/Nub.Lang/Nub.Lang/Input/program.nub b/Nub.Lang/Nub.Lang/Input/program.nub
index aa0891e..f21d41b 100644
--- a/Nub.Lang/Nub.Lang/Input/program.nub
+++ b/Nub.Lang/Nub.Lang/Input/program.nub
@@ -4,7 +4,32 @@ let STD_OUT = 1;
 let STD_ERR = 2;
 
 func main() {
-    write("test\n");
+    test
+    (
+        "a\n",
+        "b\n",
+        "c\n",
+        "d\n",
+        "e\n",
+        "f\n",
+        "g\n",
+        "h\n",
+        "i\n",
+        "j\n",
+     );
+}
+
+func test(a: String, b: String, c: String, d: String, e: String, f: String, g: String, h: String, i: String, j: String) {
+    write(a);
+    write(b);
+    write(c);
+    write(d);
+    write(e);
+    write(f);
+    write(g);
+    write(h);
+    write(i);
+    write(j);
 }
 
 func write(msg: String) {
diff --git a/Nub.Lang/Nub.Lang/Parsing/Parser.cs b/Nub.Lang/Nub.Lang/Parsing/Parser.cs
index fa16e61..e2921bd 100644
--- a/Nub.Lang/Nub.Lang/Parsing/Parser.cs
+++ b/Nub.Lang/Nub.Lang/Parsing/Parser.cs
@@ -56,6 +56,7 @@ public class Parser
             while (!TryExpectSymbol(Symbol.CloseParen))
             {
                 parameters.Add(ParseFuncParameter());
+                TryExpectSymbol(Symbol.Comma);
             }
         }