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6502: Fix and optimize sign extension

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This commit is contained in:
Karol Stasiak 2020-04-02 00:22:15 +02:00
parent d08f7ee77c
commit 7ce088514f
4 changed files with 74 additions and 24 deletions
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2
src/main/scala/millfork/OptimizationPresets.scala
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@ -179,6 +179,7 @@ object OptimizationPresets {
AlwaysGoodOptimizations.SimplifiableStackOperation,
LaterOptimizations.UseBit,
LaterOptimizations.ReplaceableLoad,
LaterOptimizations.BranchlessSignExtension,
)
val Good: List[AssemblyOptimization[AssemblyLine]] = List[AssemblyOptimization[AssemblyLine]](
@ -261,6 +262,7 @@ object OptimizationPresets {
UseAccumulatorInsteadOfYRegister,
VariableToRegisterOptimization,
TwoVariablesToIndexRegistersOptimization,
LaterOptimizations.BranchlessSignExtension,
)
val QuickPreset: List[AssemblyOptimization[AssemblyLine]] = List[AssemblyOptimization[AssemblyLine]](

27
src/main/scala/millfork/assembly/mos/opt/LaterOptimizations.scala
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@ -559,7 +559,34 @@ object LaterOptimizations {
)
val BranchlessSignExtension = new RuleBasedAssemblyOptimization("Branchless sign extension",
needsFlowInfo = FlowInfoRequirement.BothFlows,
(NotFixed & HasOpcode(LDA) & HasAddrModeIn(Absolute, ZeroPage, AbsoluteX, IndexedX, IndexedY, AbsoluteY, ZeroPageX) & HasClear(State.D)) ~
(Elidable & HasOpcode(ORA) & HasImmediate(0x7F)) ~
(Elidable & HasOpcode(BMI) & MatchParameter(10)) ~
(Elidable & HasOpcode(LDA) & HasImmediate(0)) ~
(Elidable & HasOpcode(LABEL) & IsNotALabelUsedManyTimes & MatchParameter(10) & DoesntMatterWhatItDoesWith(State.V)) ~~> { code =>
List(AssemblyLine.immediate(LDA, 0x7F), code.head.copy(opcode = CMP), AssemblyLine.immediate(SBC, 0x7F))
},
(NotFixed & HasOpcode(LDA) & HasAddrModeIn(Absolute, ZeroPage, AbsoluteX, IndexedX, IndexedY, AbsoluteY, ZeroPageX) & HasClear(State.D)) ~
(Elidable & HasOpcode(AND) & HasImmediate(0x80)) ~
(Elidable & HasOpcode(BPL) & MatchParameter(10)) ~
(Elidable & HasOpcode(LDA) & HasImmediate(0xff)) ~
(Elidable & HasOpcode(LABEL) & IsNotALabelUsedManyTimes & MatchParameter(10) & DoesntMatterWhatItDoesWith(State.V)) ~~> { code =>
List(AssemblyLine.immediate(LDA, 0x7F), code.head.copy(opcode = CMP), AssemblyLine.immediate(SBC, 0x7F))
},
)
// AssemblyLine.immediate(ORA, 0x7F),
// AssemblyLine.relative(BMI, label),
// AssemblyLine.immediate(LDA, 0),
// AssemblyLine.label(label))
// use the lists in OptimizationPresets to actually add these to the normal pipeline
val All = List(
BranchlessSignExtension,
CommutativeInPlaceModifications,
DontUseIndexRegisters,
DoubleLoadToDifferentRegisters,

17
src/main/scala/millfork/compiler/mos/MosStatementCompiler.scala
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@ -61,9 +61,9 @@ object MosStatementCompiler extends AbstractStatementCompiler[AssemblyLine] {
AssemblyLine.zeropage(STA, reg,i).copy(elidability = Elidability.Volatile))
}.toList
} else Nil)
val someRegisterA = Some(b, RegisterVariable(MosRegister.A, b))
val someRegisterAX = Some(w, RegisterVariable(MosRegister.AX, w))
val someRegisterYA = Some(w, RegisterVariable(MosRegister.YA, w))
// val someRegisterA = Some(b, RegisterVariable(MosRegister.A, b))
// val someRegisterAX = Some(w, RegisterVariable(MosRegister.AX, w))
// val someRegisterYA = Some(w, RegisterVariable(MosRegister.YA, w))
lazy val returnInstructions = if (m.interrupt) {
if (ctx.options.flag(CompilationFlag.EmitNative65816Opcodes)) {
if (zpRegisterSize > 0) {
@ -241,6 +241,7 @@ object MosStatementCompiler extends AbstractStatementCompiler[AssemblyLine] {
case s : ReturnDispatchStatement =>
MosReturnDispatch.compile(ctx, s) -> Nil
case ReturnStatement(Some(e)) =>
val exprType = AbstractExpressionCompiler.getExpressionType(ctx, e)
(m.returnType match {
case _: BooleanType =>
m.returnType.size match {
@ -248,9 +249,9 @@ object MosStatementCompiler extends AbstractStatementCompiler[AssemblyLine] {
ctx.log.error("Cannot return anything from a void function", statement.position)
stackPointerFixBeforeReturn(ctx) ++ returnInstructions
case 1 =>
MosExpressionCompiler.compile(ctx, e, someRegisterA, NoBranching) ++ stackPointerFixBeforeReturn(ctx, preserveA = true) ++ returnInstructions
MosExpressionCompiler.compile(ctx, e, Some(exprType, RegisterVariable(MosRegister.A, b)), NoBranching) ++ stackPointerFixBeforeReturn(ctx, preserveA = true) ++ returnInstructions
case 2 =>
MosExpressionCompiler.compile(ctx, e, someRegisterAX, NoBranching) ++ stackPointerFixBeforeReturn(ctx, preserveA = true, preserveX = true) ++ returnInstructions
MosExpressionCompiler.compile(ctx, e, Some(exprType, RegisterVariable(MosRegister.AX, w)), NoBranching) ++ stackPointerFixBeforeReturn(ctx, preserveA = true, preserveX = true) ++ returnInstructions
case _ =>
// TODO: is this case ever used?
MosExpressionCompiler.compileAssignment(ctx, e, VariableExpression(ctx.function.name + "`return")) ++
@ -267,14 +268,14 @@ object MosStatementCompiler extends AbstractStatementCompiler[AssemblyLine] {
ctx.log.error("Cannot return anything from a void function", statement.position)
stackPointerFixBeforeReturn(ctx) ++ List(AssemblyLine.discardAF(), AssemblyLine.discardXF(), AssemblyLine.discardYF()) ++ returnInstructions
case 1 =>
MosExpressionCompiler.compile(ctx, e, someRegisterA, NoBranching) ++ stackPointerFixBeforeReturn(ctx, preserveA = true) ++ List(AssemblyLine.discardXF(), AssemblyLine.discardYF()) ++ returnInstructions
MosExpressionCompiler.compile(ctx, e, Some(exprType, RegisterVariable(MosRegister.A, w)), NoBranching) ++ stackPointerFixBeforeReturn(ctx, preserveA = true) ++ List(AssemblyLine.discardXF(), AssemblyLine.discardYF()) ++ returnInstructions
case 2 =>
// TODO: ???
val stackPointerFix = stackPointerFixBeforeReturn(ctx, preserveA = true, preserveY = true)
if (stackPointerFix.isEmpty) {
MosExpressionCompiler.compile(ctx, e, someRegisterAX, NoBranching) ++ List(AssemblyLine.discardYF()) ++ returnInstructions
MosExpressionCompiler.compile(ctx, e, Some(exprType, RegisterVariable(MosRegister.AX, w)), NoBranching) ++ List(AssemblyLine.discardYF()) ++ returnInstructions
} else {
MosExpressionCompiler.compile(ctx, e, someRegisterYA, NoBranching) ++
MosExpressionCompiler.compile(ctx, e, Some(exprType, RegisterVariable(MosRegister.YA, w)), NoBranching) ++
stackPointerFix ++
List(AssemblyLine.implied(TAX), AssemblyLine.implied(TYA), AssemblyLine.discardYF()) ++
returnInstructions

52
src/test/scala/millfork/test/SignExtensionSuite.scala
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@ -14,11 +14,11 @@ class SignExtensionSuite extends FunSuite with Matchers {
| word output @$c000
| void main () {
| sbyte b
| b = -1
| b = -2
| output = b
| }
""".stripMargin){m =>
m.readWord(0xc000) should equal(0xffff)
m.readWord(0xc000) should equal(0xfffe)
}
}
test("Sbyte to Word 2") {
@ -28,9 +28,9 @@ class SignExtensionSuite extends FunSuite with Matchers {
| output = b()
| }
| sbyte b() {
| return -1
| return -2
| }
""".stripMargin){m => m.readWord(0xc000) should equal(0xffff)}
""".stripMargin){m => m.readWord(0xc000) should equal(0xfffe)}
}
test("Sbyte to Long") {
EmuCrossPlatformBenchmarkRun(Cpu.Mos, Cpu.Z80, Cpu.Intel8080, Cpu.Sharp, Cpu.Intel8086)("""
@ -75,12 +75,12 @@ class SignExtensionSuite extends FunSuite with Matchers {
| word output @$c000
| void main () {
| sbyte b
| b = -1
| b = -2
| memory_barrier()
| output = byte(b)
| }
""".stripMargin){m =>
m.readWord(0xc000) should equal(0x00ff)
m.readWord(0xc000) should equal(0x00fe)
}
}
@ -89,12 +89,12 @@ class SignExtensionSuite extends FunSuite with Matchers {
| word output @$c000
| void main () {
| sbyte b
| b = -1
| b = -2
| memory_barrier()
| output = word(byte(b))
| }
""".stripMargin){m =>
m.readWord(0xc000) should equal(0x00ff)
m.readWord(0xc000) should equal(0x00fe)
}
}
@ -102,11 +102,11 @@ class SignExtensionSuite extends FunSuite with Matchers {
EmuUnoptimizedCrossPlatformRun(Cpu.Mos, Cpu.Z80, Cpu.Motorola6809)("""
| word output @$c000
| void main () {
| output = f($ff)
| output = f($f4)
| }
| noinline word f(byte x) = sbyte(x)
""".stripMargin){m =>
m.readWord(0xc000) should equal(0xffff)
m.readWord(0xc000) should equal(0xfff4)
}
}
@ -130,11 +130,11 @@ class SignExtensionSuite extends FunSuite with Matchers {
|word output @$c000
|word output2 @$c002
|void main() {
| output = -1
| output = -3
| output2 = -30000
|}
|""".stripMargin) { m =>
m.readWord(0xc000) should equal(0xffff)
m.readWord(0xc000) should equal(0xfffd)
m.readWord(0xc002).toShort.toInt should equal(-30000)
}
}
@ -146,12 +146,12 @@ class SignExtensionSuite extends FunSuite with Matchers {
|
|void main() {
| static volatile signed16 tmp
| tmp = -1
| tmp = -3
| memory_barrier()
| output = tmp
|}
|""".stripMargin){ m =>
m.readLong(0xc000) should equal(-1)
m.readLong(0xc000) should equal(-3)
}
}
@ -162,13 +162,33 @@ class SignExtensionSuite extends FunSuite with Matchers {
|
|void main() {
| static volatile signed16 tmp
| tmp = -1
| tmp = -3
| output = 0
| memory_barrier()
| output += tmp
|}
|""".stripMargin){ m =>
m.readLong(0xc000) should equal(-1)
m.readLong(0xc000) should equal(-3)
}
}
test("Trivial implicit sbyte to word extension") {
EmuCrossPlatformBenchmarkRun(Cpu.Mos, Cpu.Z80, Cpu.Motorola6809)(
"""
|word output @$c000
|
|sbyte c
|
|noinline word f() {
| return c
|}
|
|void main() {
| c = -2
| output = f()
|}
|""".stripMargin){ m =>
m.readWord(0xc000) should equal(0xFFFE)
}
}