diff --git a/compiler/res/prog8lib/virtual/floats.p8 b/compiler/res/prog8lib/virtual/floats.p8
index 5ac120312..beed68e96 100644
--- a/compiler/res/prog8lib/virtual/floats.p8
+++ b/compiler/res/prog8lib/virtual/floats.p8
@@ -174,6 +174,7 @@ sub normalize(float value) -> float {
 }
 
 sub push(float value) {
+    ; note: this *should* be inlined, however since the VM has separate program counter and value stacks, this also works
     %ir {{
         loadm.f  fr65535,floats.push.value
         push.f  fr65535
@@ -182,6 +183,7 @@ sub push(float value) {
 }
 
 sub pop() -> float {
+    ; note: this *should* be inlined, however since the VM has separate program counter and value stacks, this also works
     %ir {{
         pop.f  fr65535
         returnr.f fr65535
diff --git a/compiler/src/prog8/CompilerMain.kt b/compiler/src/prog8/CompilerMain.kt
index cfb79679f..04d9c7777 100644
--- a/compiler/src/prog8/CompilerMain.kt
+++ b/compiler/src/prog8/CompilerMain.kt
@@ -37,6 +37,7 @@ fun pathFrom(stringPath: String, vararg rest: String): Path  = FileSystems.getDe
 private fun compileMain(args: Array<String>): Boolean {
     val cli = ArgParser("prog8compiler", prefixStyle = ArgParser.OptionPrefixStyle.JVM)
     val asmListfile by cli.option(ArgType.Boolean, fullName = "asmlist", description = "make the assembler produce a listing file as well")
+    val checkSource by cli.option(ArgType.Boolean, fullName = "check", description = "quickly check program for errors, no output will be produced")
     val symbolDefs by cli.option(ArgType.String, fullName = "D", description = "define assembly symbol(s) with -D SYMBOL=VALUE").multiple()
     val startEmulator1 by cli.option(ArgType.Boolean, fullName = "emu", description = "auto-start emulator after successful compilation")
     val startEmulator2 by cli.option(ArgType.Boolean, fullName = "emu2", description = "auto-start alternative emulator after successful compilation")
@@ -142,8 +143,8 @@ private fun compileMain(args: Array<String>): Boolean {
                 val filepath = pathFrom(filepathRaw).normalize()
                 val compilerArgs = CompilerArguments(
                     filepath,
-                    dontOptimize != true,
-                    dontWriteAssembly != true,
+                    if(checkSource==true) false else dontOptimize != true,
+                    if(checkSource==true) false else dontWriteAssembly != true,
                     warnSymbolShadowing == true,
                     quietAssembler == true,
                     asmListfile == true,
@@ -161,6 +162,10 @@ private fun compileMain(args: Array<String>): Boolean {
                     outputPath
                 )
                 val compilationResult = compileProgram(compilerArgs)
+
+                if(checkSource==true)
+                    println("No output produced.")
+
                 if(compilationResult!=null)
                     results.add(compilationResult)
             }
@@ -214,8 +219,8 @@ private fun compileMain(args: Array<String>): Boolean {
             try {
                 val compilerArgs = CompilerArguments(
                     filepath,
-                    dontOptimize != true,
-                    dontWriteAssembly != true,
+                    if(checkSource==true) false else dontOptimize != true,
+                    if(checkSource==true) false else dontWriteAssembly != true,
                     warnSymbolShadowing == true,
                     quietAssembler == true,
                     asmListfile == true,
@@ -233,6 +238,10 @@ private fun compileMain(args: Array<String>): Boolean {
                     outputPath
                 )
                 val result = compileProgram(compilerArgs)
+
+                if(checkSource==true)
+                    println("No output produced.")
+
                 if(result==null)
                     return false
                 else
diff --git a/docs/source/compiling.rst b/docs/source/compiling.rst
index dde1a4ed9..35ab3685d 100644
--- a/docs/source/compiling.rst
+++ b/docs/source/compiling.rst
@@ -172,6 +172,9 @@ One or more .p8 module files
 ``-asmlist``
     Generate an assembler listing file as well.
 
+``-check``
+    Quickly check the program for errors. No output will be produced.
+
 ``-breakinstr``
     Also output a CPU instruction for a ``%breakpoint``, as well as the entry in the vice monitor list file.
     This can be useful on emulators/systems that don't parse the breakpoint information in the list file,
diff --git a/docs/source/todo.rst b/docs/source/todo.rst
index d3dd9dc1b..5b57b5e57 100644
--- a/docs/source/todo.rst
+++ b/docs/source/todo.rst
@@ -2,7 +2,7 @@
 TODO
 ====
 
-- add -nowarnunused, or %option ignore_unused (module scope), to suppress all warnings about unused symbols. Useful in libraries.
+- add -nowarnunused, or %option ignore_unused (module and block scope), to suppress all warnings about unused symbols. Useful in libraries.
    put this in all library code, like %option no_symbol_prefixing, and get rid of the "trick" it uses currently to suppress unused symbol warnings for library modules.
 
 - [on branch: shortcircuit] investigate McCarthy evaluation again? this may also reduce code size perhaps for things like if a>4 or a<2 ....