Files
prog8/codeGenCpu6502/src/prog8/codegen/cpu6502/FunctionCallAsmGen.kt
2025-10-03 01:22:24 +02:00

384 lines
19 KiB
Kotlin

package prog8.codegen.cpu6502
import prog8.code.StNodeType
import prog8.code.ast.*
import prog8.code.core.*
import prog8.codegen.cpu6502.assignment.AsmAssignSource
import prog8.codegen.cpu6502.assignment.AsmAssignTarget
import prog8.codegen.cpu6502.assignment.AsmAssignment
import prog8.codegen.cpu6502.assignment.TargetStorageKind
internal class FunctionCallAsmGen(private val program: PtProgram, private val asmgen: AsmGen6502Internal) {
internal fun translateFunctionCallStatement(stmt: PtFunctionCall) {
translateFunctionCall(stmt)
// just ignore any result values from the function call.
}
internal fun optimizeIntArgsViaCpuRegisters(params: List<PtSubroutineParameter>): Boolean {
// When the parameter(s) are passed via an explicit register or register pair,
// we consider them NOT to be optimized into (possibly different) CPU registers.
// Just load them in whatever the register spec says.
return when (params.size) {
1 -> params[0].register == null && (params[0].type.isWordOrByteOrBool || params[0].type.isPointer)
2 -> params[0].type.isByteOrBool && params[1].type.isByteOrBool && params[0].register == null && params[1].register == null
else -> false
}
}
internal fun translateFunctionCall(call: PtFunctionCall) {
// Output only the code to set up the parameters and perform the actual call
// NOTE: does NOT output the code to deal with the result values!
// NOTE: does NOT output code to save/restore the X register for this call! Every caller should deal with this in their own way!!
// (you can use subroutine.shouldSaveX() and saveX()/restoreX() routines as a help for this)
val symbol = asmgen.symbolTable.lookup(call.name)!!
if(symbol.type == StNodeType.LABEL) {
require(call.void)
asmgen.out(" jsr ${asmgen.asmSymbolName(symbol.scopedNameString)}")
return
}
val sub = symbol.astNode as IPtSubroutine
val subAsmName = asmgen.asmSymbolName(call.name)
if(sub is PtAsmSub) {
argumentsViaRegisters(sub, call)
if (sub.inline) {
// inline the subroutine. (regardless of optimization settings!)
// we do this by copying the subroutine's statements at the call site.
// NOTE: *if* there is a return statement, it will be the only one, and the very last statement of the subroutine
// (this condition has been enforced by an ast check earlier)
asmgen.out(" \t; inlined routine follows: ${sub.name}")
sub.children.forEach { asmgen.translate(it as PtInlineAssembly) }
asmgen.out(" \t; inlined routine end: ${sub.name}")
} else {
val bank = sub.address?.constbank?.toString()
if(bank==null) {
val varbank = if(sub.address?.varbank==null) null else asmgen.asmVariableName(sub.address!!.varbank!!)
if(varbank!=null) {
if(asmgen.options.romable)
TODO("no codegen yet for non-const bank in subroutine call that's usable in ROM ${call.position}")
// self-modifying code: set jsrfar bank argument
when(asmgen.options.compTarget.name) {
"cx16" -> {
// JSRFAR can jump to a banked RAM address as well!
asmgen.out("""
php
pha
lda $varbank
sta +
pla
plp
jsr cx16.JSRFAR
.word $subAsmName ; ${sub.address!!.address.toHex()}
+ .byte 0 ; modified"""
)
}
"c64" -> {
asmgen.out("""
php
pha
lda $varbank
sta +
pla
plp
jsr c64.x16jsrfar
.word $subAsmName ; ${sub.address!!.address.toHex()}
+ .byte 0 ; modified"""
)
}
"c128" -> {
asmgen.out("""
php
pha
lda $varbank
sta +
pla
plp
jsr c128.x16jsrfar
.word $subAsmName ; ${sub.address!!.address.toHex()}
+ .byte 0 ; modified"""
)
}
else -> throw AssemblyError("callfar is not supported on the selected compilation target")
}
} else {
asmgen.out(" jsr $subAsmName")
}
}
else {
when(asmgen.options.compTarget.name) {
"cx16" -> {
// JSRFAR can jump to a banked RAM address as well!
asmgen.out("""
jsr cx16.JSRFAR
.word $subAsmName ; ${sub.address!!.address.toHex()}
.byte $bank"""
)
}
"c64" -> {
asmgen.out("""
jsr c64.x16jsrfar
.word $subAsmName ; ${sub.address!!.address.toHex()}
.byte $bank"""
)
}
"c128" -> {
asmgen.out("""
jsr c128.x16jsrfar
.word $subAsmName ; ${sub.address!!.address.toHex()}
.byte $bank"""
)
}
else -> throw AssemblyError("callfar is not supported on the selected compilation target")
}
}
}
}
else if(sub is PtSub) {
val parameters = sub.signature.children.filterIsInstance<PtSubroutineParameter>()
if(optimizeIntArgsViaCpuRegisters(parameters)) {
// Note that if the args fit into cpu registers, we don't concern ourselves here
// if they should be put into regular subroutine parameter variables, or the R0-R15 register variables.
// That is now up to the subroutine itself.
useCpuRegistersForArgs(call.args, sub)
} else {
// arguments via variables
val paramValues = parameters.zip(call.args)
val (normalParams, registerParams) = paramValues.partition { (it.first.register == null) }
if (normalParams.isNotEmpty()) {
for (p in normalParams)
argumentViaVariable(sub, p.first, p.second)
}
if (registerParams.isNotEmpty()) {
// the R0-R15 'registers' are not really registers. They're just special variables.
for (p in registerParams)
argumentViaVariable(sub, p.first, p.second)
}
}
asmgen.out(" jsr $subAsmName")
}
else throw AssemblyError("invalid sub type")
// remember: dealing with the X register and/or dealing with return values is the responsibility of the caller
}
private fun useCpuRegistersForArgs(args: List<PtExpression>, sub: PtSub) {
val params = sub.signature.children.filterIsInstance<PtSubroutineParameter>()
when(params.size) {
1 -> {
val register = if (params[0].type.isByteOrBool) RegisterOrPair.A else RegisterOrPair.AY
argumentViaRegister(sub, IndexedValue(0, params[0]), args[0], register)
}
2 -> {
if(params[0].type.isByteOrBool && params[1].type.isByteOrBool) {
// 2 byte params, second in Y, first in A
if(asmgen.needAsaveForExpr(args[0]) && !asmgen.needAsaveForExpr(args[1])) {
// first 0 then 1
argumentViaRegister(sub, IndexedValue(0, params[0]), args[0], RegisterOrPair.A)
argumentViaRegister(sub, IndexedValue(1, params[1]), args[1], RegisterOrPair.Y)
} else if(!asmgen.needAsaveForExpr(args[0]) && asmgen.needAsaveForExpr(args[1])) {
// first 1 then 0
argumentViaRegister(sub, IndexedValue(1, params[1]), args[1], RegisterOrPair.Y)
argumentViaRegister(sub, IndexedValue(0, params[0]), args[0], RegisterOrPair.A)
} else {
argumentViaRegister(sub, IndexedValue(0, params[0]), args[0], RegisterOrPair.A)
if (asmgen.needAsaveForExpr(args[1]))
asmgen.out(" pha")
argumentViaRegister(sub, IndexedValue(1, params[1]), args[1], RegisterOrPair.Y)
if (asmgen.needAsaveForExpr(args[1]))
asmgen.out(" pla")
}
} else {
throw AssemblyError("cannot use registers for word+byte")
}
}
else -> throw AssemblyError("cannot use cpu registers for >2 arguments")
}
}
private fun usesOtherRegistersWhileEvaluating(arg: PtExpression): Boolean {
return when(arg) {
is PtBuiltinFunctionCall -> {
if (arg.name in arrayOf("lsb", "msb", "lsw", "msw"))
return usesOtherRegistersWhileEvaluating(arg.args[0])
if (arg.name == "mkword" || arg.name == "mklong2")
return usesOtherRegistersWhileEvaluating(arg.args[0]) || usesOtherRegistersWhileEvaluating(arg.args[1])
if (arg.name == "mklong")
return usesOtherRegistersWhileEvaluating(arg.args[0]) || usesOtherRegistersWhileEvaluating(arg.args[1]) ||
usesOtherRegistersWhileEvaluating(arg.args[2]) || usesOtherRegistersWhileEvaluating(arg.args[3])
return !arg.isSimple()
}
is PtAddressOf -> false
is PtIdentifier -> false
is PtIrRegister -> false
is PtMemoryByte -> arg.address !is PtNumber && arg.address !is PtIdentifier
is PtNumber -> false
is PtBool -> false
else -> true
}
}
private fun argumentsViaRegisters(sub: PtAsmSub, call: PtFunctionCall) {
val registersUsed = mutableListOf<RegisterOrStatusflag>()
fun usedA() = registersUsed.any {it.registerOrPair==RegisterOrPair.A || it.registerOrPair==RegisterOrPair.AX || it.registerOrPair==RegisterOrPair.AY}
fun usedX() = registersUsed.any {it.registerOrPair==RegisterOrPair.X || it.registerOrPair==RegisterOrPair.AX || it.registerOrPair==RegisterOrPair.XY}
fun usedY() = registersUsed.any {it.registerOrPair==RegisterOrPair.Y || it.registerOrPair==RegisterOrPair.AY || it.registerOrPair==RegisterOrPair.XY}
if(sub.parameters.size==1) {
argumentViaRegister(sub, IndexedValue(0, sub.parameters.single().second), call.args[0])
} else {
val optimalEvalOrder = asmsub6502ArgsEvalOrder(sub)
optimalEvalOrder.forEach {
val param = sub.parameters[it]
val arg = call.args[it]
registersUsed += if(usesOtherRegistersWhileEvaluating(arg)) {
if(!registersUsed.any{r -> r.statusflag!=null || r.registerOrPair in CpuRegisters})
argumentViaRegister(sub, IndexedValue(it, param.second), arg)
else if(registersUsed.any { r-> r.statusflag!=null }) {
throw AssemblyError("call argument evaluation problem: can't save cpu statusregister parameter ${call.position}")
}
else {
if(usedX()) asmgen.saveRegisterStack(CpuRegister.X, usedA())
if(usedY()) asmgen.saveRegisterStack(CpuRegister.Y, usedA())
if(usedA()) asmgen.saveRegisterStack(CpuRegister.A, usedA())
val used = argumentViaRegister(sub, IndexedValue(it, param.second), arg)
if(usedA()) asmgen.restoreRegisterStack(CpuRegister.A, false)
if(usedY()) asmgen.restoreRegisterStack(CpuRegister.Y, true)
if(usedX()) asmgen.restoreRegisterStack(CpuRegister.X, true)
used
}
} else {
argumentViaRegister(sub, IndexedValue(it, param.second), arg)
}
}
}
}
private fun argumentViaVariable(sub: PtSub, parameter: PtSubroutineParameter, value: PtExpression) {
// pass parameter via a regular variable (not via registers)
if(!isArgumentTypeCompatible(value.type, parameter.type))
throw AssemblyError("argument type incompatible")
val reg = parameter.register
if(reg!=null) {
require(reg in Cx16VirtualRegisters) { "can only use R0-R15 'registers' here" }
val varName = "cx16.${reg.name.lowercase()}"
asmgen.assignExpressionToVariable(value, varName, parameter.type)
} else {
val varName = asmgen.asmVariableName(sub.scopedName + "." + parameter.name)
asmgen.assignExpressionToVariable(value, varName, parameter.type)
}
}
private fun argumentViaRegister(sub: IPtSubroutine, parameter: IndexedValue<PtSubroutineParameter>, value: PtExpression, registerOverride: RegisterOrPair? = null): RegisterOrStatusflag {
// pass argument via a register parameter
if(!isArgumentTypeCompatible(value.type, parameter.value.type))
throw AssemblyError("argument type incompatible")
val paramRegister: RegisterOrStatusflag = when(sub) {
is PtAsmSub -> if(registerOverride==null) sub.parameters[parameter.index].first else RegisterOrStatusflag(registerOverride, null)
is PtSub -> RegisterOrStatusflag(registerOverride!!, null)
}
val statusflag = paramRegister.statusflag
val register = paramRegister.registerOrPair
val requiredDt = parameter.value.type
if(requiredDt!=value.type) {
if(value.type.largerSizeThan(requiredDt))
throw AssemblyError("can only convert byte values to word param types")
}
if (statusflag!=null) {
if(requiredDt!=value.type)
throw AssemblyError("for statusflag, byte or bool value is required")
if (statusflag == Statusflag.Pc) {
// this boolean param needs to be set last, right before the jsr
// for now, this is already enforced on the subroutine definition by the Ast Checker
when(value) {
is PtNumber -> {
val carrySet = value.number.toInt() != 0
asmgen.out(if(carrySet) " sec" else " clc")
}
is PtBool -> {
asmgen.out(if(value.value) " sec" else " clc")
}
is PtIdentifier -> {
val sourceName = asmgen.asmVariableName(value)
// note: cannot use X register here to store A because it might be used for other arguments
asmgen.out("""
pha
clc
lda $sourceName
beq +
sec
+ pla""")
}
else -> {
asmgen.assignExpressionToRegister(value, RegisterOrPair.A)
asmgen.out(" ror a")
}
}
} else throw AssemblyError("can only use Carry as status flag parameter")
return RegisterOrStatusflag(null, statusflag)
}
else {
// via register or register pair
register!!
if(requiredDt.largerSizeThan(value.type)) {
// we need to sign extend the source, do this via temporary word variable
asmgen.assignExpressionToVariable(value, "P8ZP_SCRATCH_W1", DataType.UBYTE)
asmgen.signExtendVariableLsb("P8ZP_SCRATCH_W1", value.type.base)
asmgen.assignVariableToRegister("P8ZP_SCRATCH_W1", register, null, Position.DUMMY)
} else {
val scope = value.definingISub()
val target: AsmAssignTarget =
if(parameter.value.type.isByte && register.isWord())
AsmAssignTarget(TargetStorageKind.REGISTER, asmgen, parameter.value.type, scope, value.position, register = register)
else {
AsmAssignTarget.fromRegisters(register, parameter.value.type.isSigned, value.position, scope, asmgen)
}
val src = if(value.type.isPassByRef) {
if(value is PtIdentifier) {
val addr = PtAddressOf(value.type.typeForAddressOf(false), false, Position.DUMMY)
addr.add(value)
addr.parent = scope as PtNode
AsmAssignSource.fromAstSource(addr, program, asmgen).adjustSignedUnsigned(target)
} else {
AsmAssignSource.fromAstSource(value, program, asmgen).adjustSignedUnsigned(target)
}
} else {
AsmAssignSource.fromAstSource(value, program, asmgen).adjustSignedUnsigned(target)
}
asmgen.translateNormalAssignment(AsmAssignment(src, listOf(target), program.memsizer, target.position), scope)
}
return RegisterOrStatusflag(register, null)
}
}
private fun isArgumentTypeCompatible(argType: DataType, paramType: DataType): Boolean {
if(argType isAssignableTo paramType)
return true
if(argType.isBool && paramType.isBool)
return true
if(argType.isByte && paramType.isByte)
return true
if(argType.isWord && paramType.isWord)
return true
// we have a special rule for some types.
// strings are assignable to UWORD, for example, and vice versa
if(argType.isString && paramType.isUnsignedWord)
return true
if(argType.isUnsignedWord && paramType.isString)
return true
return false
}
}