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tiny tweak in asm optimizer

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This commit is contained in:
Irmen de Jong 2022-02-08 02:19:50 +01:00
parent abda837d2f
commit 1635612430
1 changed files with 8 additions and 6 deletions
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14
codeGenCpu6502/src/prog8/codegen/cpu6502/AsmOptimizer.kt
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@ -66,6 +66,7 @@ fun optimizeAssembly(lines: MutableList<String>, machine: IMachineDefinition, pr
private fun String.isBranch() = this.startsWith("b")
private fun String.isStoreReg() = this.startsWith("sta") || this.startsWith("sty") || this.startsWith("stx")
private fun String.isStoreRegOrZero() = this.isStoreReg() || this.startsWith("stz")
private fun String.isLoadReg() = this.startsWith("lda") || this.startsWith("ldy") || this.startsWith("ldx")
private class Modification(val lineIndex: Int, val remove: Boolean, val replacement: String?)
@ -253,12 +254,13 @@ private fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<Stri
}
}
}
/*
sta A1
sty A2
sty A2 ; ... or stz
lda A1 ; can be removed if not followed by a branch instruction
*/
if(!overlappingMods && first.isStoreReg() && second.isStoreReg()
if(!overlappingMods && first.isStoreReg() && second.isStoreRegOrZero()
&& third.isLoadReg() && !fourth.isBranch()) {
val reg1 = first[2]
val reg3 = third[2]
@ -297,10 +299,10 @@ private fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<Stri
}
/*
sta A
sta A
sta A ; or stz double store, remove this first one
sta A ; or stz
*/
if(!overlappingMods && first.isStoreReg() && second.isStoreReg()) {
if(!overlappingMods && first.isStoreRegOrZero() && second.isStoreRegOrZero()) {
if(first[2]==second[2]) {
val firstvalue = first.substring(4)
val secondvalue = second.substring(4)
@ -308,7 +310,7 @@ private fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<Stri
val address = getAddressArg(first, program)
if(address==null || !machine.isIOAddress(address)) {
overlappingMods = true
mods.add(Modification(lines[1].index, true, null))
mods.add(Modification(lines[0].index, true, null))
}
}
}