got rid of unnecessary cast of boolean expressions by making their type dynamically adjust to byte or word

codeGenVirtual/src/prog8/codegen/virtual/BuiltinFuncGen.kt

@@ -3,6 +3,7 @@ package prog8.codegen.virtual
 import prog8.code.ast.PtBuiltinFunctionCall
 import prog8.code.ast.PtNumber
 import prog8.code.ast.PtString
+import prog8.code.core.WordDatatypes
 import prog8.vm.Opcode
 import prog8.vm.Syscall
 import prog8.vm.VmDataType
@@ -82,6 +83,7 @@ internal class BuiltinFuncGen(private val codeGen: CodeGen, private val exprGen:
                     code += VmCodeInstruction(Opcode.LOADR, VmDataType.BYTE, reg1=resultRegister, reg2=0)
             }
             "peek" -> {
+                // should just be a memory read
                 val addressReg = codeGen.vmRegisters.nextFree()
                 code += exprGen.translateExpression(call.args.single(), addressReg)
                 code += VmCodeInstruction(Opcode.LOADI, VmDataType.BYTE, reg1 = resultRegister, reg2=addressReg)
@@ -91,6 +93,21 @@ internal class BuiltinFuncGen(private val codeGen: CodeGen, private val exprGen:
                 code += exprGen.translateExpression(call.args.single(), addressReg)
                 code += VmCodeInstruction(Opcode.LOADI, VmDataType.WORD, reg1 = resultRegister, reg2=addressReg)
             }
+            "poke" -> {
+                // should just be a memory write
+                val addressReg = codeGen.vmRegisters.nextFree()
+                val valueReg = codeGen.vmRegisters.nextFree()
+                code += exprGen.translateExpression(call.args[0], addressReg)
+                code += exprGen.translateExpression(call.args[1], valueReg)
+                code += VmCodeInstruction(Opcode.STOREI, VmDataType.BYTE, reg1 = addressReg, reg2=valueReg)
+            }
+            "pokew" -> {
+                val addressReg = codeGen.vmRegisters.nextFree()
+                val valueReg = codeGen.vmRegisters.nextFree()
+                code += exprGen.translateExpression(call.args[0], addressReg)
+                code += exprGen.translateExpression(call.args[1], valueReg)
+                code += VmCodeInstruction(Opcode.STOREI, VmDataType.WORD, reg1 = addressReg, reg2=valueReg)
+            }
             "mkword" -> {
                 val msbReg = codeGen.vmRegisters.nextFree()
                 val lsbReg = codeGen.vmRegisters.nextFree()

codeOptimizers/src/prog8/optimizer/BinExprSplitter.kt

@@ -3,10 +3,7 @@ package prog8.optimizer
 import prog8.ast.IStatementContainer
 import prog8.ast.Node
 import prog8.ast.Program
-import prog8.ast.expressions.AugmentAssignmentOperators
+import prog8.ast.expressions.*
-import prog8.ast.expressions.BinaryExpression
-import prog8.ast.expressions.IdentifierReference
-import prog8.ast.expressions.TypecastExpression
 import prog8.ast.getTempVar
 import prog8.ast.statements.AssignTarget
 import prog8.ast.statements.Assignment
@@ -97,7 +94,8 @@ X =      BinExpr                                    X   =   LeftExpr
                 // we can see if we can unwrap the binary expression by working on a new temporary variable
                 // (that has the type of the expression), and then finally doing the typecast.
                 // Once it's outside the typecast, the regular splitting can commence.
-                val (tempVarName, _) = program.getTempVar(origExpr.inferType(program).getOr(DataType.UNDEFINED))
+                val tempvarDt = origExpr.inferType(program).getOr(DataType.UNDEFINED)
+                val (tempVarName, _) = program.getTempVar(tempvarDt)
                 val assignTempVar = Assignment(
                     AssignTarget(IdentifierReference(tempVarName, typecast.position), null, null, typecast.position),
                     typecast.expression, AssignmentOrigin.OPTIMIZER, typecast.position

compiler/src/prog8/compiler/astprocessing/TypecastsAdder.kt

@@ -114,6 +114,10 @@ class TypecastsAdder(val program: Program, val options: CompilationOptions, val
                     if(valuetype in IterableDatatypes && targettype==DataType.UWORD)
                         // special case, don't typecast STR/arrays to UWORD, we support those assignments "directly"
                         return noModifications
+                    if((assignment.value as? BinaryExpression)?.operator in ComparisonOperators) {
+                        // special case, treat a boolean comparison result as the same type as the target value to avoid needless casts later
+                        return noModifications
+                    }
                     val modifications = mutableListOf<IAstModification>()
                     addTypecastOrCastedValueModification(modifications, assignment.value, targettype, assignment)
                     return modifications

compiler/test/TestOptimization.kt

@@ -253,7 +253,7 @@ class TestOptimization: FunSpec({
         (initY2.value as NumericLiteral).number shouldBe 11.0
     }
 
-    test("typecasted assignment from ubyte logical expressoin to uword var") {
+    test("not-typecasted assignment from ubyte logical expression to uword var") {
         val src = """
             main {
                 sub start() {
@@ -265,13 +265,11 @@ class TestOptimization: FunSpec({
         """
         val result = compileText(C64Target(), false, src, writeAssembly = false)!!
 
-        // ww = ((( not bb as uword)  or  not ww) as uword)
         val wwAssign = result.program.entrypoint.statements.last() as Assignment
-        val expr = wwAssign.value as TypecastExpression
+        val expr = wwAssign.value as BinaryExpression
 
         wwAssign.target.identifier?.nameInSource shouldBe listOf("ww")
-        expr.type shouldBe DataType.UWORD
+        expr.inferType(result.program) istype DataType.UWORD shouldBe true
-        expr.expression.inferType(result.program) istype DataType.UBYTE shouldBe true
     }
 
     test("intermediate assignment steps have correct types for codegen phase (BeforeAsmGenerationAstChanger)") {

compilerAst/src/prog8/ast/expressions/AstExpressions.kt

@@ -195,8 +195,21 @@ class BinaryExpression(var left: Expression, var operator: String, var right: Ex
 
     override fun referencesIdentifier(nameInSource: List<String>) = left.referencesIdentifier(nameInSource) || right.referencesIdentifier(nameInSource)
     override fun inferType(program: Program): InferredTypes.InferredType {
+
         val leftDt = left.inferType(program)
         val rightDt = right.inferType(program)
+
+        fun dynamicBooleanType(): InferredTypes.InferredType {
+            // as a special case, an expression yielding a boolean result, adapts the result
+            // type to what is required (byte or word), to avoid useless type casting
+            return if(parent is TypecastExpression)
+                InferredTypes.InferredType.known((parent as TypecastExpression).type)
+            else if(parent is Assignment)
+                (parent as Assignment).target.inferType(program)
+            else
+                InferredTypes.InferredType.known(DataType.UBYTE)
+        }
+
         return when (operator) {
             "+", "-", "*", "%", "/" -> {
                 if (!leftDt.isKnown || !rightDt.isKnown)
@@ -221,13 +234,14 @@ class BinaryExpression(var left: Expression, var operator: String, var right: Ex
             "and", "or", "xor",
             "<", ">",
             "<=", ">=",
-            "==", "!=" -> InferredTypes.knownFor(DataType.UBYTE)
+            "==", "!=" -> dynamicBooleanType()
             "<<", ">>" -> leftDt
-            "in" -> InferredTypes.knownFor(DataType.UBYTE)
+            "in" -> dynamicBooleanType()
             else -> throw FatalAstException("resulting datatype check for invalid operator $operator")
         }
     }
 
+
     companion object {
         fun commonDatatype(leftDt: DataType, rightDt: DataType,
                            left: Expression?, right: Expression?): Pair<DataType, Expression?> {

docs/source/todo.rst

@@ -3,7 +3,6 @@ TODO
 
 For next release
 ^^^^^^^^^^^^^^^^
-- vm: implement all operators in the virtualmachine
 - vm: codegen: more optimal code for loops ending on 0 (BNZ?)
 - pipe operator: allow non-unary function calls in the pipe that specify the other argument(s) in the calls.
 - writeAssembly(): make it possible to actually get rid of the VarDecl nodes by fixing the rest of the code mentioned there.

examples/test.p8

@@ -6,27 +6,15 @@
 
 main {
 
-    ubyte global = 42
-
     sub start() {
-        uword begin = c64.RDTIM16()
+        ubyte value1 = 99
+        ubyte value2 = 222
 
-        ubyte shift
+        uword @shared result = $ffff
-        repeat 60 {
+        result = value1 != value2
-            ubyte yy
-            for yy in 0 to 59 {
-                ubyte xx
-                for xx in 0 to 79 {
-                    ubyte color = yy+xx+shift
-                    txt.setcc2(xx,yy,81,color)       ; 356
-                }
-            }
-            shift++
-        }
 
-        uword duration = c64.RDTIM16()-begin
+        txt.print_uwhex(result, true)
-        txt.print_uw(duration)
+        txt.nl()
-        txt.print("     \n")
 
         ; a "pixelshader":
 ;        syscall1(8, 0)      ; enable lo res creen

virtualmachine/src/prog8/vm/VirtualMachine.kt

@@ -713,7 +713,7 @@ class VirtualMachine(val memory: Memory, program: List<Instruction>) {
         when(i.type!!) {
             VmDataType.BYTE -> {
                 val value = registers.getUW(i.reg1!!)
-                val newValue = 0xea31 // value.toUByte()*256u + (value.toInt() ushr 8).toUInt()
+                val newValue = value.toUByte()*256u + (value.toInt() ushr 8).toUInt()
                 registers.setUW(i.reg1, newValue.toUShort())
             }
             VmDataType.WORD -> TODO("swap.w requires 32-bits registers")