6502: Detect pointer variables that have to be in the zeropage more accurately

src/main/scala/millfork/env/Environment.scala

@@ -1083,8 +1083,8 @@ class Environment(val parent: Option[Environment], val prefix: String, val cpuFa
 
   def collectPointies(stmts: Seq[Statement]): Set[String] = {
     val pointies: mutable.Set[String] = new mutable.HashSet()
-        pointies ++= stmts.flatMap(_.getAllPointies)
-        pointies ++ getAliases.filterKeys(pointies).values
+    pointies ++= stmts.flatMap(_.getAllPointies)
+    pointies ++= getAliases.filterKeys(pointies).values
     log.trace("Collected pointies: " + pointies)
     pointies.toSet
   }
@@ -1133,7 +1133,7 @@ class Environment(val parent: Option[Environment], val prefix: String, val cpuFa
     } else {
       new Environment(Some(this), name + "$", cpuFamily, options)
     }
-    stmt.params.foreach(p => env.registerParameter(p, options))
+    stmt.params.foreach(p => env.registerParameter(p, options, pointies))
     def params: ParamSignature = if (stmt.assembly) {
       AssemblyParamSignature(stmt.params.map {
         pd =>
@@ -1423,14 +1423,14 @@ class Environment(val parent: Option[Environment], val prefix: String, val cpuFa
     }
   }
 
-  def registerParameter(stmt: ParameterDeclaration, options: CompilationOptions): Unit = {
+  def registerParameter(stmt: ParameterDeclaration, options: CompilationOptions, pointies: Set[String]): Unit = {
     val typ = get[Type](stmt.typ)
     val b = get[Type]("byte")
     val w = get[Type]("word")
     val p = get[Type]("pointer")
     stmt.assemblyParamPassingConvention match {
       case ByVariable(name) =>
-        val zp = typ.isPointy // TODO
+        val zp = typ.isPointy || pointies(name) // TODO
         val v = UninitializedMemoryVariable(prefix + name, typ, if (zp) VariableAllocationMethod.Zeropage else VariableAllocationMethod.Auto, None, defaultVariableAlignment(options, 2), isVolatile = false)
         addThing(v, stmt.position)
         registerAddressConstant(v, stmt.position, options, Some(typ))

src/main/scala/millfork/node/Node.scala

@@ -612,6 +612,18 @@ case class FunctionDeclarationStatement(name: String,
   override def getAllExpressions: List[Expression] = address.toList ++ statements.getOrElse(Nil).flatMap(_.getAllExpressions)
 
   override def withChangedBank(bank: String): BankedDeclarationStatement = copy(bank = Some(bank))
+
+  override def getAllPointies: Seq[String] = statements match {
+    case None => Seq.empty
+    case Some(stmts) =>
+      val locals = stmts.flatMap{
+        case s:VariableDeclarationStatement => Some(s.name)
+        case s:ArrayDeclarationStatement => Some(s.name)
+        case _ => None
+      }.toSet
+      val pointies = stmts.flatMap(_.getAllPointies).toSet
+      (pointies -- locals).toSeq
+  }
 }
 
 sealed trait ExecutableStatement extends Statement

src/test/scala/millfork/test/PointerSuite.scala

@@ -1,7 +1,7 @@
 package millfork.test
 
 import millfork.Cpu
-import millfork.test.emu.{EmuCrossPlatformBenchmarkRun, EmuUnoptimizedCrossPlatformRun, ShouldNotCompile}
+import millfork.test.emu.{EmuCrossPlatformBenchmarkRun, EmuUnoptimizedCrossPlatformRun, EmuUnoptimizedRun, ShouldNotCompile}
 import org.scalatest.{AppendedClues, FunSuite, Matchers}
 
 /**
@@ -427,4 +427,30 @@ class PointerSuite extends FunSuite with Matchers with AppendedClues {
       m.readWord(0xc100) should equal(0x400)
     }
   }
+
+  test("Pointers should remain at zero page if used as pointers in assembly") {
+    val m = EmuUnoptimizedRun(
+      """
+        | word output @$c000
+        | pointer p
+        | volatile pointer q1
+        | volatile pointer q2
+        | volatile pointer q3
+        | volatile pointer q4
+        | volatile pointer q5
+        | volatile pointer q6
+        | volatile pointer q7
+        | volatile pointer q8
+        | array arr [250] @$0
+        | void main () {
+        |   asm {
+        |     lda (p),y
+        |   }
+        |   output = p.addr
+        |   q1 = q2 + q3 + q4 + q5 + q6 + q7 + q8
+        | }
+        |""".stripMargin)
+    m.readWord(0xc000) should be <(256)
+
+  }
 }