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allow asmsub routines with multiple return values to be called (special case for return values in status register)

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Irmen de Jong 2020-10-07 00:06:42 +02:00
parent 71cd8b6d51
commit 71fd98e39e
12 changed files with 130 additions and 51 deletions
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6
compiler/src/prog8/ast/expressions/AstExpressions.kt
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@ -872,6 +872,12 @@ class FunctionCall(override var target: IdentifierReference,
return InferredTypes.void() // no return value
if(stmt.returntypes.size==1)
return InferredTypes.knownFor(stmt.returntypes[0])
// multiple return values. Can occur for asmsub routines. If there is exactly one register return value, take that.
val numRegisterReturns = stmt.asmReturnvaluesRegisters.count { it.registerOrPair!=null }
if(numRegisterReturns==1)
return InferredTypes.InferredType.known(DataType.UBYTE)
return InferredTypes.unknown() // has multiple return types... so not a single resulting datatype possible
}
else -> return InferredTypes.unknown()

52
compiler/src/prog8/ast/processing/AstChecker.kt
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@ -346,17 +346,15 @@ internal class AstChecker(private val program: Program,
}
override fun visit(assignment: Assignment) {
// assigning from a functioncall COULD return multiple values (from an asm subroutine)
if(assignment.value is FunctionCall) {
val stmt = (assignment.value as FunctionCall).target.targetStatement(program.namespace)
if (stmt is Subroutine && stmt.isAsmSubroutine) {
if(stmt.returntypes.size>1)
errors.err("It's not possible to store the multiple results of this asmsub call; you should use a small block of custom inline assembly for this.", assignment.value.position)
else {
val idt = assignment.target.inferType(program, assignment)
if(!idt.isKnown || stmt.returntypes.single()!=idt.typeOrElse(DataType.BYTE)) {
errors.err("return type mismatch", assignment.value.position)
}
if (stmt is Subroutine) {
val idt = assignment.target.inferType(program, assignment)
if(!idt.isKnown) {
errors.err("return type mismatch", assignment.value.position)
}
if(stmt.returntypes.size <= 1 && stmt.returntypes.single()!=idt.typeOrElse(DataType.BYTE)) {
errors.err("return type mismatch", assignment.value.position)
}
}
}
@ -386,7 +384,8 @@ internal class AstChecker(private val program: Program,
}
val targetDt = assignment.target.inferType(program, assignment)
if(assignment.value.inferType(program) != targetDt) {
val valueDt = assignment.value.inferType(program)
if(valueDt.isKnown && valueDt != targetDt) {
if(targetDt.typeOrElse(DataType.STRUCT) in IterableDatatypes)
errors.err("cannot assign value to string or array", assignment.value.position)
else
@ -446,12 +445,8 @@ internal class AstChecker(private val program: Program,
checkValueTypeAndRange(targetDatatype.typeOrElse(DataType.BYTE), constVal)
} else {
val sourceDatatype = assignment.value.inferType(program)
if (!sourceDatatype.isKnown) {
if (assignment.value is FunctionCall) {
val targetStmt = (assignment.value as FunctionCall).target.targetStatement(program.namespace)
if (targetStmt != null)
errors.err("function call doesn't return a suitable value to use in assignment", assignment.value.position)
} else
if (sourceDatatype.isUnknown) {
if (assignment.value !is FunctionCall)
errors.err("assignment value is invalid or has no proper datatype", assignment.value.position)
} else {
checkAssignmentCompatible(targetDatatype.typeOrElse(DataType.BYTE), assignTarget,
@ -791,6 +786,8 @@ internal class AstChecker(private val program: Program,
}
override fun visit(expr: BinaryExpression) {
super.visit(expr)
val leftIDt = expr.left.inferType(program)
val rightIDt = expr.right.inferType(program)
if(!leftIDt.isKnown || !rightIDt.isKnown)
@ -836,7 +833,6 @@ internal class AstChecker(private val program: Program,
errors.err("right operand is not numeric", expr.right.position)
if(leftDt!=rightDt)
errors.err("left and right operands aren't the same type", expr.left.position)
super.visit(expr)
}
override fun visit(typecast: TypecastExpression) {
@ -898,6 +894,28 @@ internal class AstChecker(private val program: Program,
if(error!=null)
errors.err(error, functionCall.position)
// check the functions that return multiple returnvalues.
val stmt = functionCall.target.targetStatement(program.namespace)
if (stmt is Subroutine) {
if (stmt.returntypes.size > 1) {
// Currently, it's only possible to handle ONE (or zero) return values from a subroutine.
// asmsub routines can have multiple return values, for instance in 2 different registers.
// It's not (yet) possible to handle these multiple return values because assignments
// are only to a single unique target at the same time.
// EXCEPTION:
// if the asmsub returns multiple values and one of them is via a status register bit,
// it *is* possible to handle them by just actually assigning the register value and
// dealing with the status bit as just being that, the status bit after the call.
val (returnRegisters, returnStatusflags) = stmt.asmReturnvaluesRegisters.partition { rr -> rr.registerOrPair != null }
if (returnRegisters.isEmpty() || returnRegisters.size == 1) {
if (returnStatusflags.any())
errors.warn("this asmsub also has one or more return 'values' in one of the status flags", functionCall.position)
} else {
errors.err("It's not possible to store the multiple result values of this asmsub call; you should use a small block of custom inline assembly for this.", functionCall.position)
}
}
}
super.visit(functionCall)
}

16
compiler/src/prog8/ast/processing/VerifyFunctionArgTypes.kt
View File

@ -4,10 +4,9 @@ import prog8.ast.IFunctionCall
import prog8.ast.INameScope
import prog8.ast.Program
import prog8.ast.base.DataType
import prog8.ast.expressions.Expression
import prog8.ast.expressions.FunctionCall
import prog8.ast.statements.BuiltinFunctionStatementPlaceholder
import prog8.ast.statements.FunctionCallStatement
import prog8.ast.statements.Subroutine
import prog8.ast.statements.*
import prog8.compiler.CompilerException
import prog8.functions.BuiltinFunctions
@ -43,7 +42,6 @@ class VerifyFunctionArgTypes(val program: Program) : IAstVisitor {
val argtypes = call.args.map { it.inferType(program).typeOrElse(DataType.STRUCT) }
val target = call.target.targetStatement(scope)
if (target is Subroutine) {
// asmsub types are not checked specifically at this time
if(call.args.size != target.parameters.size)
return "invalid number of arguments"
val paramtypes = target.parameters.map { it.type }
@ -53,6 +51,16 @@ class VerifyFunctionArgTypes(val program: Program) : IAstVisitor {
val expected = paramtypes[mismatch].toString()
return "argument ${mismatch + 1} type mismatch, was: $actual expected: $expected"
}
if(target.isAsmSubroutine) {
if(target.asmReturnvaluesRegisters.size>1) {
// multiple return values will NOT work inside an expression.
// they MIGHT work in a regular assignment or just a function call statement.
val parent = if(call is Statement) call.parent else if(call is Expression) call.parent else null
if(call !is FunctionCallStatement && parent !is Assignment && parent !is VarDecl) {
return "can't use multiple return values here"
}
}
}
}
else if (target is BuiltinFunctionStatementPlaceholder) {
val func = BuiltinFunctions.getValue(target.name)

2
compiler/src/prog8/ast/statements/AstStatements.kt
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@ -416,7 +416,7 @@ data class AssignTarget(var identifier: IdentifierReference?,
}
}
fun inferType(program: Program, stmt: Statement): InferredTypes.InferredType {
fun inferType(program: Program, stmt: Statement): InferredTypes.InferredType { // TODO why does this have the extra 'stmt' scope parameter???
if (identifier != null) {
val symbol = program.namespace.lookup(identifier!!.nameInSource, stmt) ?: return InferredTypes.unknown()
if (symbol is VarDecl) return InferredTypes.knownFor(symbol.datatype)

4
compiler/src/prog8/compiler/Main.kt
View File

@ -56,7 +56,7 @@ fun compileProgram(filepath: Path,
optimizeAst(programAst, errors)
postprocessAst(programAst, errors, compilationOptions)
printAst(programAst) // TODO
// printAst(programAst)
if(writeAssembly)
programName = writeAssembly(programAst, errors, outputDir, optimize, compilationOptions)
@ -219,7 +219,7 @@ private fun writeAssembly(programAst: Program, errors: ErrorReporter, outputDir:
programAst.processAstBeforeAsmGeneration(errors)
errors.handle()
printAst(programAst) // TODO
// printAst(programAst)
CompilationTarget.instance.machine.initializeZeropage(compilerOptions)
val assembly = CompilationTarget.instance.asmGenerator(

11
compiler/src/prog8/compiler/target/c64/codegen/AsmGen.kt
View File

@ -588,9 +588,10 @@ internal class AsmGen(private val program: Program,
if (builtinFunc != null) {
builtinFunctionsAsmGen.translateFunctioncallStatement(stmt, builtinFunc)
} else {
functioncallAsmGen.translateFunctionCall(stmt)
// discard any results from the stack:
val sub = stmt.target.targetSubroutine(program.namespace)!!
val preserveStatusRegisterAfterCall = sub.asmReturnvaluesRegisters.any {it.statusflag!=null}
functioncallAsmGen.translateFunctionCall(stmt, preserveStatusRegisterAfterCall)
// discard any results from the stack:
val returns = sub.returntypes.zip(sub.asmReturnvaluesRegisters)
for ((t, reg) in returns) {
if (reg.stack) {
@ -598,6 +599,8 @@ internal class AsmGen(private val program: Program,
else if (t == DataType.FLOAT) out(" inx | inx | inx")
}
}
if(preserveStatusRegisterAfterCall)
out(" plp\t; restore status flags from call")
}
}
is Assignment -> assignmentAsmGen.translate(stmt)
@ -763,8 +766,8 @@ internal class AsmGen(private val program: Program,
internal fun translateFunctioncallExpression(functionCall: FunctionCall, signature: FSignature) =
builtinFunctionsAsmGen.translateFunctioncallExpression(functionCall, signature)
internal fun translateFunctionCall(functionCall: FunctionCall) =
functioncallAsmGen.translateFunctionCall(functionCall)
internal fun translateFunctionCall(functionCall: FunctionCall, preserveStatusRegisterAfterCall: Boolean) =
functioncallAsmGen.translateFunctionCall(functionCall, preserveStatusRegisterAfterCall)
internal fun translateNormalAssignment(assign: AsmAssignment) =
assignmentAsmGen.translateNormalAssignment(assign)

3
compiler/src/prog8/compiler/target/c64/codegen/ExpressionsAsmGen.kt
View File

@ -949,7 +949,8 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
asmgen.translateFunctioncallExpression(expression, builtinFunc)
} else {
val sub = expression.target.targetSubroutine(program.namespace)!!
asmgen.translateFunctionCall(expression)
val preserveStatusRegisterAfterCall = sub.asmReturnvaluesRegisters.any {it.statusflag!=null}
asmgen.translateFunctionCall(expression, preserveStatusRegisterAfterCall)
val returns = sub.returntypes.zip(sub.asmReturnvaluesRegisters)
for ((_, reg) in returns) {
if (!reg.stack) {

8
compiler/src/prog8/compiler/target/c64/codegen/FunctionCallAsmGen.kt
View File

@ -13,7 +13,7 @@ import prog8.compiler.target.c64.codegen.assignment.*
internal class FunctionCallAsmGen(private val program: Program, private val asmgen: AsmGen) {
internal fun translateFunctionCall(stmt: IFunctionCall) {
internal fun translateFunctionCall(stmt: IFunctionCall, preserveStatusRegisterAfterCall: Boolean) {
// output the code to setup the parameters and perform the actual call
// does NOT output the code to deal with the result values!
val sub = stmt.target.targetSubroutine(program.namespace) ?: throw AssemblyError("undefined subroutine ${stmt.target}")
@ -57,6 +57,12 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
}
asmgen.out(" jsr $subName")
if(preserveStatusRegisterAfterCall) {
asmgen.out(" php\t; save status flags from call")
// note: the containing statement (such as the FunctionCallStatement or the Assignment or the Expression)
// must take care of popping this value again at the end!
}
if(saveX)
asmgen.restoreRegister(CpuRegister.X)
}

19
compiler/src/prog8/compiler/target/c64/codegen/assignment/AsmAssignment.kt
View File

@ -6,6 +6,7 @@ import prog8.ast.expressions.*
import prog8.ast.statements.AssignTarget
import prog8.ast.statements.Assignment
import prog8.ast.statements.DirectMemoryWrite
import prog8.ast.statements.Subroutine
import prog8.compiler.AssemblyError
import prog8.compiler.target.c64.codegen.AsmGen
@ -118,8 +119,23 @@ internal class AsmAssignSource(val kind: SourceStorageKind,
AsmAssignSource(SourceStorageKind.ARRAY, program, dt, array = value)
}
else -> {
if(value is FunctionCall) {
// functioncall.
val asmSub = value.target.targetStatement(program.namespace)
if(asmSub is Subroutine && asmSub.isAsmSubroutine) {
when (asmSub.asmReturnvaluesRegisters.count { rr -> rr.registerOrPair!=null }) {
0 -> throw AssemblyError("can't translate zero return values in assignment")
1 -> {
// assignment generation itself must make sure the status register is correct after the subroutine call, if status register is involved!
return AsmAssignSource(SourceStorageKind.EXPRESSION, program, DataType.UBYTE, expression = value)
}
else -> throw AssemblyError("can't translate multiple return values in assignment")
}
}
}
val dt = value.inferType(program).typeOrElse(DataType.STRUCT)
AsmAssignSource(SourceStorageKind.EXPRESSION, program, dt, expression = value)
return AsmAssignSource(SourceStorageKind.EXPRESSION, program, dt, expression = value)
}
}
}
@ -160,6 +176,7 @@ internal class AsmAssignment(val source: AsmAssignSource,
init {
if(target.register !in setOf(RegisterOrPair.XY, RegisterOrPair.AX, RegisterOrPair.AY))
require(source.datatype != DataType.STRUCT) { "must not be placeholder datatype" }
require(source.datatype.memorySize() == target.datatype.memorySize()) { "source and target datatype must be same storage class" }
}
}

30
compiler/src/prog8/compiler/target/c64/codegen/assignment/AssignmentAsmGen.kt
View File

@ -123,20 +123,22 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
is ArrayIndexedExpression -> throw AssemblyError("source kind should have been array")
is DirectMemoryRead -> throw AssemblyError("source kind should have been memory")
is TypecastExpression -> assignTypeCastedValue(assign.target, value.type, value.expression, assign)
// is FunctionCall -> {
// if (assign.target.kind == TargetStorageKind.STACK) {
// asmgen.translateExpression(value)
// assignStackValue(assign.target)
// } else {
// val functionName = value.target.nameInSource.last()
// val builtinFunc = BuiltinFunctions[functionName]
// if (builtinFunc != null) {
// println("!!!!BUILTIN-FUNCCALL target=${assign.target.kind} $value") // TODO optimize certain functions?
// }
// asmgen.translateExpression(value)
// assignStackValue(assign.target)
// }
// }
is FunctionCall -> {
if(value.target.targetSubroutine(program.namespace)?.isAsmSubroutine==true) {
// TODO handle asmsub functioncalls specifically, without shoving stuff on the estack
asmgen.translateExpression(value)
assignStackValue(assign.target)
val sub = value.target.targetSubroutine(program.namespace)
if(sub!=null && sub.asmReturnvaluesRegisters.any { it.statusflag != null }) {
// the expression translation will have generated a 'php' instruction earlier.
asmgen.out(" plp\t; restore status flags from call")
}
} else {
// regular subroutine, return values are (for now) always done via the stack... TODO optimize this
asmgen.translateExpression(value)
assignStackValue(assign.target)
}
}
else -> {
// everything else just evaluate via the stack.
asmgen.translateExpression(value)

15
docs/source/syntaxreference.rst
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@ -503,6 +503,8 @@ takes no parameters. If the subroutine returns a value, usually you assign it t
If you're not interested in the return value, prefix the function call with the ``void`` keyword.
Otherwise the compiler will warn you about discarding the result of the call.
Multiple return values
^^^^^^^^^^^^^^^^^^^^^^
Normal subroutines can only return zero or one return values.
However, the special ``asmsub`` routines (implemented in assembly code) or ``romsub`` routines
(referencing a routine in kernel ROM) can return more than one return value.
@ -510,9 +512,16 @@ For example a status in the carry bit and a number in A, or a 16-bit value in A/
It is not possible to process the results of a call to these kind of routines
directly from the language, because only single value assignments are possible.
You can still call the subroutine and not store the results.
But if you want to do something with the values it returns, you'll have to write
a small block of custom inline assembly that does the call and stores the values
appropriately. Don't forget to save/restore the registers if required.
**There is an exception:** if there's just one return value in a register, and one or more others that are returned
as bits in the status register (such as the Carry bit), the compiler allows you to call the subroutine.
It will then store the result value in a variable if required, and *keep the status register untouched
after the call* so you can use a conditional branch statement for that.
Note that this makes no sense inside an expression, so the compiler will still give an error for that.
If there really are multiple return values (other than a combined 16 bit return value in 2 registers),
you'll have to write a small block of custom inline assembly that does the call and stores the values
appropriately. Don't forget to save/restore any registers that are modified.
Subroutine definitions

15
examples/test.p8
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@ -8,11 +8,20 @@ main {
str planet_name = "12345678"
sub start() {
; TODO make this work, with a warning about Pc:
c64.OPEN() ; works: function call droppign the value but preserving the statusregister
if_cs
return
ubyte status
status = c64.OPEN() ; open 1,8,0,"$"
; TODO make this work as well, with the same warning:
ubyte status2 = c64.OPEN() ; open 1,8,0,"$"
if_cs
return
; ; TODO make this work as well, with the same warning:
; ubyte status2 = c64.OPEN() ; open 1,8,0,"$"
if_cs
return