From 69c82d90a862d9418d8f12f164eccdd1459ed455 Mon Sep 17 00:00:00 2001
From: Karol Stasiak <karol.m.stasiak@gmail.com>
Date: Mon, 30 Dec 2019 14:28:37 +0100
Subject: [PATCH] 6502: Allow assigning between two statically allocated
 pointers; fixes #25

---
 .../compiler/mos/MosExpressionCompiler.scala  | 17 +++++++++--
 .../scala/millfork/test/ForLoopSuite.scala    | 29 +++++++++++++++++++
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/src/main/scala/millfork/compiler/mos/MosExpressionCompiler.scala b/src/main/scala/millfork/compiler/mos/MosExpressionCompiler.scala
index 657ab8a4..a0ea64cb 100644
--- a/src/main/scala/millfork/compiler/mos/MosExpressionCompiler.scala
+++ b/src/main/scala/millfork/compiler/mos/MosExpressionCompiler.scala
@@ -2238,9 +2238,22 @@ object MosExpressionCompiler extends AbstractExpressionCompiler[AssemblyLine] {
                                 AssemblyLine.indexedY(STA, reg, 2))
                             }
                         }
-                      case _ => ???
+                      case (MemoryAddressConstant(thT: MemoryVariable), MemoryAddressConstant(thS: MemoryVariable)) if thT.name != thS.name =>
+                        prepare ++ prepareSource ++ (0 until targetType.size).flatMap { i =>
+                          if (i >= sourceType.size) List(
+                            if (i == 0) AssemblyLine.immediate(LDY, sourceOffset) else AssemblyLine.implied(INY),
+                            AssemblyLine.immediate(LDA, 0),
+                            AssemblyLine.indexedY(STA, thT))
+                          else List(
+                            if (i == 0) AssemblyLine.immediate(LDY, sourceOffset) else AssemblyLine.implied(INY),
+                            AssemblyLine.indexedY(LDA, thS),
+                            AssemblyLine.indexedY(STA, thT))
+                        }
+                      case _ =>
+                        ???
                     }
-                  case _ => ???
+                  case _ =>
+                    ???
                 }
               case _ =>
                 (targetType.size, am) match {
diff --git a/src/test/scala/millfork/test/ForLoopSuite.scala b/src/test/scala/millfork/test/ForLoopSuite.scala
index 13ba46d1..2270bb49 100644
--- a/src/test/scala/millfork/test/ForLoopSuite.scala
+++ b/src/test/scala/millfork/test/ForLoopSuite.scala
@@ -478,4 +478,33 @@ class ForLoopSuite extends FunSuite with Matchers {
         |}
       """.stripMargin).readByte(0xc000) should equal(45)
   }
+
+  test("Some pointers in loops") {
+    val code =
+      """
+        |struct Sprite {
+        |    byte y
+        |}
+        |
+        |array(Sprite) sprites [20]
+        |Sprite test
+        |
+        |void main() {
+        |    byte i
+        |    test = Sprite(1)
+        |    pointer.Sprite test_pointer
+        |    test_pointer = test.pointer
+        |
+        |    sprites[0] = Sprite(5)
+        |    pointer.Sprite current_sprite
+        |    current_sprite = pointer.Sprite(sprites.pointer)
+        |    for i,0,until,20 {
+        |        current_sprite->y = test_pointer->y
+        |    }
+        |}
+        |""".stripMargin
+    EmuUnoptimizedCrossPlatformRun(Cpu.Mos, Cpu.Z80, Cpu.Motorola6809) (code) { m =>
+      // OK
+    }
+  }
 }