Allow refering to labels from other functions in assembly (fixes #101)

docs/lang/assembly.md

@@ -52,6 +52,17 @@ Global label names have to start with a letter and can contain digits, underscor
 Local label names (available since Millfork 0.3.22) start with a period and are visible only in the given function.
 Anonymous labels designated with `+` or `-` are also not supported.
 
+Referring to a global label with an offset requires wrapping it in `label(…)`:
+
+    STA .local_opcode              // ok
+    STA label(.local_opcode)       // ok
+    STA .local_opcode + 1          // ok
+    STA label(.local_opcode) + 1   // ok
+    STA global_opcode              // ok
+    STA label(global_opcode)       // ok
+    STA global_opcode + 1          // NOT OK
+    sta label(global_opcode) + 1   // ok
+
 Assembly can refer to variables and constants defined in Millfork,
 but you need to be careful with using absolute vs immediate addressing:
 

docs/lang/assembly6809.md

@@ -27,6 +27,17 @@ Global label names have to start with a letter and can contain digits, underscor
 Local label names (available since Millfork 0.3.22) start with a period and are visible only in the given function.
 Anonymous labels designated with `+` or `-` are also not supported.
 
+Referring to a global label with an offset requires wrapping it in `label(…)`:
+
+    STA .local_opcode              // ok
+    STA label(.local_opcode)       // ok
+    STA .local_opcode + 1          // ok
+    STA label(.local_opcode) + 1   // ok
+    STA global_opcode              // ok
+    STA label(global_opcode)       // ok
+    STA global_opcode + 1          // NOT OK
+    STA label(global_opcode) + 1   // ok
+
 Assembly can refer to variables and constants defined in Millfork,
 but you need to be careful with using absolute vs immediate addressing:
 

docs/lang/assemblyz80.md

@@ -52,6 +52,17 @@ Global label names have to start with a letter and can contain digits, underscor
 Local label names (available since Millfork 0.3.22) start with a period and are visible only in the given function.
 Anonymous labels designated with `+` or `-` are also not supported.
 
+Referring to a global label with an offset requires wrapping it in `label(…)`:
+
+    LD (.local_opcode),A              // ok
+    LD (label(.local_opcode)),A       // ok
+    LD (.local_opcode + 1),A          // ok
+    LD (label(.local_opcode) + 1),A   // ok
+    LD (global_opcode),A              // ok
+    LD (label(global_opcode)),A       // ok
+    LD (global_opcode + 1),A          // NOT OK
+    LD (label(global_opcode) + 1),A   // ok
+
 Assembly can refer to variables and constants defined in Millfork,
 but you need to be careful with using absolute vs immediate addressing:
 

src/main/scala/millfork/compiler/m6809/M6809StatementCompiler.scala

@@ -6,7 +6,7 @@ import millfork.assembly.m6809.{Inherent, MLine, MOpcode, NonExistent}
 import millfork.compiler.{AbstractCompiler, AbstractExpressionCompiler, AbstractStatementCompiler, BranchSpec, CompilationContext}
 import millfork.node.{Assignment, BlackHoleExpression, BreakStatement, ContinueStatement, DoWhileStatement, EmptyStatement, ExecutableStatement, Expression, ExpressionStatement, ForEachStatement, ForStatement, FunctionCallExpression, GotoStatement, IfStatement, LabelStatement, LiteralExpression, M6809AssemblyStatement, MemsetStatement, ReturnDispatchStatement, ReturnStatement, VariableExpression, WhileStatement}
 import millfork.assembly.m6809.MOpcode._
-import millfork.env.{BooleanType, ConstantBooleanType, FatBooleanType, Label, MemoryAddressConstant, StructureConstant, ThingInMemory}
+import millfork.env.{BooleanType, Constant, ConstantBooleanType, FatBooleanType, Label, MemoryAddressConstant, StructureConstant, ThingInMemory}
 
 /**
   * @author Karol Stasiak
@@ -58,12 +58,21 @@ object M6809StatementCompiler extends AbstractStatementCompiler[MLine] {
         }
         (eval ++ epilogue ++ rts) -> Nil
       case M6809AssemblyStatement(opcode, addrMode, expression, elidability) =>
-        ctx.env.evalForAsm(expression, opcode) match {
+        val e = ctx.env.evalForAsm(expression) match {
-          case Some(e) => List(MLine(opcode, addrMode, e, elidability)) -> Nil
+          case Some(e) => e
           case None =>
-            println(statement)
+            expression match {
-            ???
+              case VariableExpression(name) =>
+                env.maybeGet[ThingInMemory](name).map(_.toAddress).getOrElse {
+                  val fqName = if (name.startsWith(".")) env.prefix + name else name
+                  MemoryAddressConstant(Label(fqName))
+                }
+              case _ =>
+                ctx.log.error("Invalid parameter", statement.position)
+                Constant.Zero
+            }
         }
+        List(MLine(opcode, addrMode, e, elidability)) -> Nil
       case Assignment(destination, source) =>
         if (destination == BlackHoleExpression) return M6809ExpressionCompiler.compile(ctx, source, MExpressionTarget.NOTHING, BranchSpec.None) -> Nil
         val destinationType = AbstractExpressionCompiler.getExpressionType(ctx, destination)
@@ -107,13 +116,22 @@ object M6809StatementCompiler extends AbstractStatementCompiler[MLine] {
       case s:ContinueStatement =>
         compileContinueStatement(ctx, s) -> Nil
       case M6809AssemblyStatement(opcode, addrMode, expression, elidability) =>
-        ctx.env.evalForAsm(expression, opcode) match {
+        val silent = MOpcode.Branching(opcode) || opcode == LABEL || opcode == CHANGED_MEM
-          case Some(param) =>
+        val param: Constant = ctx.env.evalForAsm(expression, silent = silent) match {
-            List(MLine(opcode, addrMode, param, elidability)) -> Nil
+          case Some(param) => param
           case None =>
-            ctx.log.error("Invalid parameter", expression.position)
+            expression match {
-            Nil -> Nil
+              case VariableExpression(name) =>
+                env.maybeGet[ThingInMemory](name).map(_.toAddress).getOrElse{
+                  val fqName = if (name.startsWith(".")) env.prefix + name else name
+                  MemoryAddressConstant(Label(fqName))
+                }
+              case _ =>
+                ctx.log.error("Invalid parameter", expression.position)
+                Constant.Zero
+            }
         }
+        List(MLine(opcode, addrMode, param, elidability)) -> Nil
       case s:LabelStatement =>
         List(MLine.label(env.prefix + s.name)) -> Nil
       case s: GotoStatement =>

src/main/scala/millfork/compiler/mos/MosStatementCompiler.scala

@@ -342,11 +342,10 @@ object MosStatementCompiler extends AbstractStatementCompiler[AssemblyLine] {
     x match {
       // TODO: hmmm
       case VariableExpression(name) =>
-        if (OpcodeClasses.ShortBranching(o) || o == JMP || o == LABEL || o == CHANGED_MEM || OpcodeClasses.HudsonTransfer(o)) {
+        val silent = OpcodeClasses.ShortBranching(o) || o == JMP || o == LABEL || o == CHANGED_MEM || OpcodeClasses.HudsonTransfer(o)
+        env.evalForAsm(x, silent = silent).orElse(env.maybeGet[ThingInMemory](name).map(_.toAddress)).getOrElse{
           val fqName = if (name.startsWith(".")) env.prefix + name else name
           MemoryAddressConstant(Label(fqName))
-        } else {
-          env.evalForAsm(x).getOrElse(env.get[ThingInMemory](name, x.position).toAddress)
         }
       case FunctionCallExpression("byte_and_pointer$", List(z, b@VariableExpression(name))) =>
         StructureConstant(env.get[StructType]("byte_and_pointer$"), List(

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

@@ -973,15 +973,15 @@ class Environment(val parent: Option[Environment], val prefix: String, val cpuFa
     }
   }
 
-  def evalForAsm(e: Expression, op: MOpcode.Value = MOpcode.NOP, silent: Boolean = false): Option[Constant] = {
+  def evalForAsm(e: Expression, silent: Boolean = false): Option[Constant] = {
     e match {
-      // TODO: hmmm
+      case FunctionCallExpression("label", List(VariableExpression(name))) if (!name.contains(".")) =>
-      case VariableExpression(name) =>
+        return Some(Label(name).toAddress)
-        import MOpcode._
+      case FunctionCallExpression("label", List(VariableExpression(name))) if (name.startsWith(".")) =>
-        if (MOpcode.Branching(op) || op == LABEL || op == CHANGED_MEM) {
+        return Some(Label(prefix + name).toAddress)
-          val fqName = if (name.startsWith(".")) prefix + name else name
+      case FunctionCallExpression("label", _) =>
-          return Some(MemoryAddressConstant(Label(fqName)))
+        log.error("Invalid label reference", e.position)
-        }
+        return Some(Constant.Zero)
       case _ =>
     }
     e match {
@@ -994,7 +994,7 @@ class Environment(val parent: Option[Environment], val prefix: String, val cpuFa
           case None =>
             if (name.startsWith(".")) Some(Label(prefix + name).toAddress)
             else {
-              if (!silent) log.warn(s"$name is not known", e.position)
+              if (!silent) log.warn(s"$name is not known. If it is a label, consider wrapping it in label(...).", e.position)
               None
             }
         }

src/test/scala/millfork/test/AssemblySuite.scala

@@ -28,6 +28,7 @@ class AssemblySuite extends FunSuite with Matchers with AppendedClues {
         | // w&x
         | asm void main () {
         |   lda #3
+        |   sta label(.l)+1
         |   sta .l+1
         |   .l: lda #55
         |   sta output
@@ -36,6 +37,56 @@ class AssemblySuite extends FunSuite with Matchers with AppendedClues {
       """.stripMargin)(_.readByte(0xc000) should equal(3))
   }
 
+  test("Self-modifying assembly 2") {
+    EmuCrossPlatformBenchmarkRun(Cpu.Mos, Cpu.Motorola6809)(
+      """
+        | byte output @$c000
+        | // w&x
+        | asm void f() {
+        |   f_data:
+        |   lda #$ff
+        |   rts
+        | }
+        |
+        | asm void main () {
+        |   lda f_data
+        |   sta f_data
+        |   lda #3
+        |   sta label(f_data)+1
+        |   lda #0
+        |   jsr f_data
+        |   sta output
+        |   lda #lo(f)
+        |   rts
+        |   ignored:}
+      """.stripMargin)(_.readByte(0xc000) should equal(3))
+  }
+
+  test("Self-modifying assembly 2 (Z80)") {
+      EmuCrossPlatformBenchmarkRun(Cpu.Z80)(
+        """
+          | byte output @$c000
+          | // w&x
+          | asm void f() {
+          |   f_data:
+          |   ld a, $ff
+          |   ret
+          | }
+          |
+          | asm void main () {
+          |   ld a,(f_data)
+          |   ld (f_data),a
+          |   ld a,3
+          |   ld (label(f_data)+1),a
+          |   ld a,0
+          |   call f_data
+          |   ld (output),a
+          |   ld b,lo(f)
+          |   ret
+          |   ignored:}
+        """.stripMargin)(_.readByte(0xc000) should equal(3))
+    }
+
   test("Assembly functions") {
     EmuBenchmarkRun(
       """