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fixed bug in assembly optimizer removing too many instructions

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This commit is contained in:
Irmen de Jong 2022-01-28 15:19:08 +01:00
parent 7b3cd71085
commit 1815cb1bc3
1 changed files with 14 additions and 10 deletions
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24
codeGenCpu6502/src/prog8/codegen/cpu6502/AsmOptimizer.kt
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@ -64,6 +64,10 @@ fun optimizeAssembly(lines: MutableList<String>, machine: IMachineDefinition, pr
return numberOfOptimizations
}
private fun String.isBranch() = this.startsWith("b")
private fun String.isStoreReg() = this.startsWith("sta") || this.startsWith("sty") || this.startsWith("stx")
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?)
private fun apply(modifications: List<Modification>, lines: MutableList<String>) {
@ -196,9 +200,9 @@ private fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<Stri
sta A1
sty A2
*/
if(first.startsWith("st") && second.startsWith("st")
&& third.startsWith("ld") && fourth.startsWith("ld")
&& fifth.startsWith("st") && sixth.startsWith("st")) {
if(first.isStoreReg() && second.isStoreReg()
&& third.isLoadReg() && fourth.isLoadReg()
&& fifth.isStoreReg() && sixth.isStoreReg()) {
val reg1 = first[2]
val reg2 = second[2]
val reg3 = third[2]
@ -227,8 +231,8 @@ private fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<Stri
lda A1 ; can be removed
ldy A2 ; can be removed if not followed by a branch instuction
*/
if(!overlappingMods && first.startsWith("st") && second.startsWith("st")
&& third.startsWith("ld") && fourth.startsWith("ld")) {
if(!overlappingMods && first.isStoreReg() && second.isStoreReg()
&& third.isLoadReg() && fourth.isLoadReg()) {
val reg1 = first[2]
val reg2 = second[2]
val reg3 = third[2]
@ -254,8 +258,8 @@ private fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<Stri
sty A2
lda A1 ; can be removed if not followed by a branch instruction
*/
if(!overlappingMods && first.startsWith("st") && second.startsWith("st")
&& third.startsWith("ld") && !fourth.startsWith("b")) {
if(!overlappingMods && first.isStoreReg() && second.isStoreReg()
&& third.isLoadReg() && !fourth.isBranch()) {
val reg1 = first[2]
val reg3 = third[2]
if(reg1==reg3) {
@ -276,7 +280,7 @@ private fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<Stri
ldy A1 ; make tay
sta A1 ; remove
*/
if(!overlappingMods && first.startsWith("sta") && second.startsWith("ld")
if(!overlappingMods && first.startsWith("sta") && second.isLoadReg()
&& third.startsWith("sta") && second.length>4) {
val firstvalue = first.substring(4)
val secondvalue = second.substring(4)
@ -296,7 +300,7 @@ private fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<Stri
sta A
sta A
*/
if(!overlappingMods && first.startsWith("st") && second.startsWith("st")) {
if(!overlappingMods && first.isStoreReg() && second.isStoreReg()) {
if(first[2]==second[2]) {
val firstvalue = first.substring(4)
val secondvalue = second.substring(4)
@ -333,7 +337,7 @@ private fun optimizeStoreLoadSame(linesByFour: List<List<IndexedValue<String>>>,
) {
val third = lines[3].value.trimStart()
val attemptRemove =
if(third.startsWith("b")) {
if(third.isBranch()) {
// a branch instruction follows, we can only remove the load instruction if
// another load instruction of the same register precedes the store instruction
// (otherwise wrong cpu flags are used)