Apple-2-SW/prog8
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optimize assignment from memory pointer with fixed byte offset

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This commit is contained in:
Irmen de Jong 2021-01-15 19:52:53 +01:00
parent 3dcef89a74
commit 9f72779cdc
2 changed files with 31 additions and 7 deletions
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37
compiler/src/prog8/compiler/target/c64/codegen/assignment/AssignmentAsmGen.kt
View File

@ -112,6 +112,15 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
}
}
SourceStorageKind.MEMORY -> {
fun assignViaExprEval(expression: Expression) {
assignExpressionToVariable(expression, asmgen.asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, assign.target.scope)
if (CompilationTarget.instance.machine.cpu == CpuType.CPU65c02)
asmgen.out(" lda (P8ZP_SCRATCH_W2)")
else
asmgen.out(" ldy #0 | lda (P8ZP_SCRATCH_W2),y")
assignRegisterByte(assign.target, CpuRegister.A)
}
val value = assign.source.memory!!
when (value.addressExpression) {
is NumericLiteralValue -> {
@ -121,14 +130,28 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
is IdentifierReference -> {
assignMemoryByte(assign.target, null, value.addressExpression as IdentifierReference)
}
else -> {
assignExpressionToVariable(value.addressExpression, asmgen.asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, assign.target.scope)
if (CompilationTarget.instance.machine.cpu == CpuType.CPU65c02)
asmgen.out(" lda (P8ZP_SCRATCH_W2)")
else
asmgen.out(" ldy #0 | lda (P8ZP_SCRATCH_W2),y")
assignRegisterByte(assign.target, CpuRegister.A)
is BinaryExpression -> {
// try to optimize simple cases like assignment from ptr+1, ptr+2...
var optimized = false
val expr = value.addressExpression as BinaryExpression
if(expr.operator=="+") {
// we can assume const operand has been moved to the right.
val constOperand = expr.right.constValue(program)
if(constOperand!=null) {
val intIndex = constOperand.number.toInt()
if(intIndex in 1..255) {
assignExpressionToVariable(expr.left, asmgen.asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, assign.target.scope)
asmgen.out(" ldy #${intIndex} | lda (P8ZP_SCRATCH_W2),y")
assignRegisterByte(assign.target, CpuRegister.A)
optimized = true
}
}
}
if(!optimized)
assignViaExprEval(expr)
}
else -> assignViaExprEval(value.addressExpression)
}
}
SourceStorageKind.EXPRESSION -> {

1
examples/test.p8
View File

@ -23,6 +23,7 @@ main {
txt.nl()
txt.nl()
txt.chrout(@(ptr))
txt.chrout(@(ptr+1))
txt.chrout(@(ptr+2))