From df1d5421be378f02ea20115be17e4ac725c68686 Mon Sep 17 00:00:00 2001
From: Karol Stasiak <karol.m.stasiak@gmail.com>
Date: Fri, 3 Jan 2020 23:08:54 +0100
Subject: [PATCH] Do not allocate variables on top of fixed-address vairables
 and arrays (fixes #26)

---
 src/main/scala/millfork/env/Environment.scala |  7 ++++++
 .../millfork/output/AbstractAssembler.scala   | 24 +++++++++++++++++++
 .../scala/millfork/test/BasicSymonTest.scala  | 15 ++++++++++++
 3 files changed, 46 insertions(+)

diff --git a/src/main/scala/millfork/env/Environment.scala b/src/main/scala/millfork/env/Environment.scala
index f7d2150c..e76bf416 100644
--- a/src/main/scala/millfork/env/Environment.scala
+++ b/src/main/scala/millfork/env/Environment.scala
@@ -131,8 +131,12 @@ class Environment(val parent: Option[Environment], val prefix: String, val cpuFa
           Nil
         case NormalParamSignature(List(MemoryVariable(_, typ, _))) if typ.size == 1 && options.platform.cpuFamily == CpuFamily.I80 =>
           Nil
+        case NormalParamSignature(List(MemoryVariable(_, typ, _))) if typ.size == 1 && options.platform.cpuFamily == CpuFamily.M6809 =>
+          Nil
         case NormalParamSignature(List(MemoryVariable(_, typ, _))) if typ.size == 2 && options.platform.cpuFamily == CpuFamily.I80 =>
           Nil
+        case NormalParamSignature(List(MemoryVariable(_, typ, _))) if typ.size == 2 && options.platform.cpuFamily == CpuFamily.M6809 =>
+          Nil
         case NormalParamSignature(List(MemoryVariable(_, typ, _))) if typ.size == 3 && options.platform.cpuFamily == CpuFamily.I80 =>
           Nil
         case NormalParamSignature(List(MemoryVariable(_, typ, _))) if typ.size == 4 && options.platform.cpuFamily == CpuFamily.I80 =>
@@ -171,6 +175,7 @@ class Environment(val parent: Option[Environment], val prefix: String, val cpuFa
             if (forZpOnly || !options.platform.hasZeroPage) {
               val addr =
                 allocators(bank).allocateBytes(bank0, callGraph, vertex, options, m.sizeInBytes, initialized = false, writeable = true, location = AllocationLocation.Zeropage, alignment = m.alignment)
+              if (log.traceEnabled) log.trace("addr $" + addr.toHexString)
               onEachVariable(m.name, bank0.index -> addr)
               List(
                 ConstantThing(m.name.stripPrefix(prefix) + "`", NumericConstant(addr, 2), p)
@@ -187,6 +192,7 @@ class Environment(val parent: Option[Environment], val prefix: String, val cpuFa
                   allocators(bank).tryAllocateZeropageBytes(bank0, callGraph, vertex, options, m.sizeInBytes, alignment = m.alignment) match {
                     case None => Nil
                     case Some(addr) =>
+                      if (log.traceEnabled) log.trace("addr $" + addr.toHexString)
                       onEachVariable(m.name, bank0.index -> addr)
                       List(
                         ConstantThing(m.name.stripPrefix(prefix) + "`", NumericConstant(addr, 2), p)
@@ -197,6 +203,7 @@ class Environment(val parent: Option[Environment], val prefix: String, val cpuFa
                 Nil
               } else {
                 val addr = allocators(bank).allocateBytes(bank0, callGraph, vertex, options, m.sizeInBytes, initialized = false, writeable = true, location = AllocationLocation.Either, alignment = m.alignment)
+                if (log.traceEnabled) log.trace("addr $" + addr.toHexString)
                 onEachVariable(m.name, bank0.index -> addr)
                 List(
                   ConstantThing(graveName, NumericConstant(addr, 2), p)
diff --git a/src/main/scala/millfork/output/AbstractAssembler.scala b/src/main/scala/millfork/output/AbstractAssembler.scala
index e824567f..01725dda 100644
--- a/src/main/scala/millfork/output/AbstractAssembler.scala
+++ b/src/main/scala/millfork/output/AbstractAssembler.scala
@@ -223,6 +223,30 @@ abstract class AbstractAssembler[T <: AbstractCode](private val program: Program
     val potentiallyInlineable: Map[String, Int] = inliningResult.potentiallyInlineableFunctions
     var functionsThatCanBeCalledFromInlinedFunctions: Set[String] = inliningResult.nonInlineableFunctions
 
+    for(th <- env.things.values) {
+      th match {
+        case tim: VariableInMemory =>
+          tim.toAddress match {
+            case NumericConstant(n, _) =>
+              val m = mem.banks(tim.bank(options))
+              for (i <- 0 until tim.typ.size) {
+                m.occupied(i + n.toInt) = true
+              }
+            case _ =>
+          }
+        case arr: MfArray =>
+          arr.toAddress match {
+            case NumericConstant(n, _) =>
+              val m = mem.banks(arr.bank(options))
+              for (i <- 0 until arr.sizeInBytes) {
+                m.occupied(i + n.toInt) = true
+              }
+            case _ =>
+          }
+        case _ =>
+      }
+    }
+
     env.allocateVariables(None, mem, callGraph, variableAllocators, options, labelMap.put, 1, forZpOnly = true)
     env.allocateVariables(None, mem, callGraph, variableAllocators, options, labelMap.put, 2, forZpOnly = true)
     env.allocateVariables(None, mem, callGraph, variableAllocators, options, labelMap.put, 3, forZpOnly = true)
diff --git a/src/test/scala/millfork/test/BasicSymonTest.scala b/src/test/scala/millfork/test/BasicSymonTest.scala
index e1a45b56..58e79334 100644
--- a/src/test/scala/millfork/test/BasicSymonTest.scala
+++ b/src/test/scala/millfork/test/BasicSymonTest.scala
@@ -191,6 +191,21 @@ class BasicSymonTest extends FunSuite with Matchers {
     }
   }
 
+  test("Allocation test 2") {
+    EmuUnoptimizedCrossPlatformRun(Cpu.Mos)(
+      """
+        | #use ZPREG_SIZE
+        | array _crap[$100-ZPREG_SIZE] @$00
+        | word output @$c000
+        | word data
+        | void main () {
+        |   output = data.addr
+        | }
+      """.stripMargin){ m =>
+      m.readWord(0xc000) should be >=(0x100)
+    }
+  }
+
   test("Preprocessor test") {
     EmuUnoptimizedCrossPlatformRun(Cpu.Mos, Cpu.Z80, Cpu.Intel8080, Cpu.Sharp)(
       """