diff --git a/src/main/scala/millfork/compiler/mos/BuiltIns.scala b/src/main/scala/millfork/compiler/mos/BuiltIns.scala
index 72f85263..1a6122a6 100644
--- a/src/main/scala/millfork/compiler/mos/BuiltIns.scala
+++ b/src/main/scala/millfork/compiler/mos/BuiltIns.scala
@@ -73,22 +73,35 @@ object BuiltIns {
           }
         case FunctionCallExpression(name, List(param)) if env.maybeGet[Type](name).isDefined =>
           return simpleOperation(opcode, ctx, param, indexChoice, preserveA, commutative, decimal)
-        case _: FunctionCallExpression | _:SumExpression if commutative =>
+        case _: FunctionCallExpression | _: SumExpression if commutative =>
           // TODO: is it ok?
-          if (ctx.options.flag(CompilationFlag.EmitEmulation65816Opcodes)) {
-            return List(AssemblyLine.implied(PHA)) ++ MosExpressionCompiler.compile(ctx.addStack(1), source, Some(b -> RegisterVariable(MosRegister.A, b)), NoBranching) ++ wrapInSedCldIfNeeded(decimal, List(
+          if (ctx.options.zpRegisterSize >= 1) {
+            val reg = ctx.env.get[ThingInMemory]("__reg")
+            return List(AssemblyLine.implied(PHA)) ++
+              MosExpressionCompiler.compileToA(ctx, source) ++
+              List(AssemblyLine.zeropage(STA, reg), AssemblyLine.implied(PLA)) ++
+              wrapInSedCldIfNeeded(decimal, List(AssemblyLine.zeropage(opcode, reg)))
+          } else if (ctx.options.flag(CompilationFlag.EmitEmulation65816Opcodes)) {
+            return List(AssemblyLine.implied(PHA)) ++ MosExpressionCompiler.compileToA(ctx.addStack(1), source) ++ wrapInSedCldIfNeeded(decimal, List(
               AssemblyLine.stackRelative(opcode, 1),
               AssemblyLine.implied(PHX)))
           } else {
-            return List(AssemblyLine.implied(PHA)) ++ MosExpressionCompiler.compile(ctx.addStack(1), source, Some(b -> RegisterVariable(MosRegister.A, b)), NoBranching) ++ wrapInSedCldIfNeeded(decimal, List(
+            return List(AssemblyLine.implied(PHA)) ++ MosExpressionCompiler.compileToA(ctx.addStack(1), source) ++ wrapInSedCldIfNeeded(decimal, List(
               AssemblyLine.implied(TSX),
               AssemblyLine.absoluteX(opcode, 0x101),
               AssemblyLine.implied(INX),
               AssemblyLine.implied(TXS))) // this TXS is fine, it won't appear in 65816 code
           }
         case _ =>
-          ctx.log.error("Right-hand-side expression is too complex", source.position)
-          return Nil
+          if (ctx.options.zpRegisterSize < 1) {
+            ctx.log.error("Right-hand-side expression requires a zero-page register", source.position)
+            return Nil
+          }
+          val reg = ctx.env.get[ThingInMemory]("__reg")
+          return List(AssemblyLine.implied(PHA)) ++
+            MosExpressionCompiler.compileToA(ctx, source) ++
+            List(AssemblyLine.zeropage(STA, reg), AssemblyLine.implied(PLA)) ++
+            wrapInSedCldIfNeeded(decimal, List(AssemblyLine.zeropage(opcode, reg)))
       }
     } {
       const =>
diff --git a/src/test/scala/millfork/test/ByteMathSuite.scala b/src/test/scala/millfork/test/ByteMathSuite.scala
index bb548d44..03f88bee 100644
--- a/src/test/scala/millfork/test/ByteMathSuite.scala
+++ b/src/test/scala/millfork/test/ByteMathSuite.scala
@@ -22,6 +22,24 @@ class ByteMathSuite extends FunSuite with Matchers with AppendedClues {
       """.stripMargin)(_.readByte(0xc000) should equal(2))
   }
 
+  test("Complex expression 2") {
+    EmuCrossPlatformBenchmarkRun(Cpu.Mos, Cpu.Z80, Cpu.Intel8080, Cpu.Sharp)(
+      """
+        | byte output @$c000
+        | void main () {
+        |  output = 50
+        |  f()
+        | }
+        | noinline void f() {
+        |   byte a
+        |   a = g()
+        |   output -= a >> 1
+        | }
+        | noinline byte g() { return 3 }
+        |
+      """.stripMargin)(_.readByte(0xc000) should equal(49))
+  }
+
   test("Byte addition") {
     EmuCrossPlatformBenchmarkRun(Cpu.Mos, Cpu.Z80, Cpu.Intel8080, Cpu.Sharp)(
       """