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Optimize some bitmask operations

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This commit is contained in:
Karol Stasiak 2021-05-05 02:58:57 +02:00
parent c51c08ad56
commit ffb46c4250
3 changed files with 42 additions and 0 deletions
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9
src/main/scala/millfork/assembly/m6809/opt/AlwaysGoodMOptimizations.scala
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@ -152,6 +152,15 @@ object AlwaysGoodMOptimizations {
(_.map(_.copy(opcode = LDD))),
(Elidable & HasImmediate(0) & HasOpcodeIn(ORB, EORB, ADDB, ORA, EORA, ADDA, ADDD) & DoesntMatterWhatItDoesWith(MState.VF, MState.ZF, MState.NF, MState.CF, MState.HF)) ~~>
(_ => Nil),
(HasOpcode(LDB)) ~
(Elidable & HasOpcode(ANDB) & HasAddrMode(Immediate) & MatchParameter(0)) ~
(Elidable & HasOpcode(BNE) & MatchParameter(1)) ~
(Elidable & HasOpcode(LDB)) ~
(HasOpcode(ANDB) & HasAddrMode(Immediate) & MatchParameter(0)) ~
(HasOpcode(BEQ)) ~
(HasOpcode(LABEL) & MatchParameter(1)) ~~> { code =>
List(code.head, code(3).copy(opcode = ORB)) ++ code.drop(4)
},
)

9
src/main/scala/millfork/assembly/mos/opt/AlwaysGoodOptimizations.scala
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@ -1605,6 +1605,15 @@ object AlwaysGoodOptimizations {
Where(ctx => ctx.get[Int](1).&(1) == 0)~~> { (lines, ctx) =>
lines.head.copy(opcode = ASL) :: lines.tail
},
(Elidable & HasOpcode(LDA)) ~
(Elidable & HasOpcode(AND) & HasAddrMode(Immediate) & MatchParameter(0)) ~
(Elidable & HasOpcode(BNE) & MatchParameter(1)) ~
(Elidable & HasOpcode(LDA)) ~
(Elidable & HasOpcode(AND) & HasAddrMode(Immediate) & MatchParameter(0)) ~
(Elidable & HasOpcode(BEQ)) ~
(Elidable & HasOpcode(LABEL) & MatchParameter(1)) ~~> { (code, ctx) =>
List(code.head, code(3).copy(opcode = ORA)) ++ code.drop(4)
},
)
val SimplifiableIndexChanging = new RuleBasedAssemblyOptimization("Simplifiable index changing",

24
src/test/scala/millfork/test/AssemblyOptimizationSuite.scala
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@ -962,4 +962,28 @@ class AssemblyOptimizationSuite extends FunSuite with Matchers {
m.readWord(0xc008) should equal(10)
}
}
test("Optimize certain bitmasking operations") {
val code =
"""
|byte output @$c000
|const byte c = 4
|
|noinline void inc(byte x, byte y) {
| if x & c != 0 || y & c != 0 { output += 1 }
|}
|
|void main() {
| output = 0
| inc(0, 0)
| inc(4, 0) // ↑
| inc(4, 4) // ↑
| inc(0, 4) // ↑
|}
|""".stripMargin
EmuCrossPlatformBenchmarkRun(Cpu.Mos, Cpu.Motorola6809)(
code) { m =>
m.readByte(0xc000) should equal(code.count(_ == '↑'))
}
}
}