added some cpu stack related assembly-level optimizations

This commit is contained in:
Irmen de Jong 2021-11-28 17:17:23 +01:00
parent f0dadc4a43
commit 47c2c0376a
4 changed files with 34 additions and 103 deletions

View File

@ -7,10 +7,6 @@ import prog8.ast.statements.VarDecl
import prog8.compilerinterface.IMachineDefinition
// TODO optimize subsequent pha/pla, phx/plx, phy/ply pairs
// TODO optimize pha/plx -> tax, pha/ply -> tay, etc.
// note: see https://wiki.nesdev.org/w/index.php/6502_assembly_optimisations
@ -357,6 +353,31 @@ private fun optimizeStoreLoadSame(linesByFour: List<List<IndexedValue<String>>>,
mods.add(Modification(lines[2].index, true, null))
}
}
else if(first=="pha" && second=="pla" ||
first=="phx" && second=="plx" ||
first=="phy" && second=="ply" ||
first=="php" && second=="plp") {
mods.add(Modification(lines[1].index, true, null))
mods.add(Modification(lines[2].index, true, null))
} else if(first=="pha" && second=="plx") {
mods.add(Modification(lines[1].index, true, null))
mods.add(Modification(lines[2].index, false, " tax"))
} else if(first=="pha" && second=="ply") {
mods.add(Modification(lines[1].index, true, null))
mods.add(Modification(lines[2].index, false, " tay"))
} else if(first=="phx" && second=="pla") {
mods.add(Modification(lines[1].index, true, null))
mods.add(Modification(lines[2].index, false, " txa"))
} else if(first=="phx" && second=="ply") {
mods.add(Modification(lines[1].index, true, null))
mods.add(Modification(lines[2].index, false, " txy"))
} else if(first=="phy" && second=="pla") {
mods.add(Modification(lines[1].index, true, null))
mods.add(Modification(lines[2].index, false, " tya"))
} else if(first=="phy" && second=="plx") {
mods.add(Modification(lines[1].index, true, null))
mods.add(Modification(lines[2].index, false, " tyx"))
}
}
return mods
}

View File

@ -143,21 +143,6 @@ class StatementOptimizer(private val program: Program,
return noModifications
}
// TODO WHAT TO DO WITH THIS:
// override fun before(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> {
// // if the first instruction in the called subroutine is a return statement with constant value, replace with the constant value
// val subroutine = functionCall.target.targetSubroutine(program)
// if(subroutine!=null) {
// val first = subroutine.statements.asSequence().filterNot { it is VarDecl || it is Directive }.firstOrNull()
// if(first is Return && first.value!=null) {
// val constval = first.value?.constValue(program)
// if(constval!=null)
// return listOf(IAstModification.ReplaceNode(functionCall, constval, parent))
// }
// }
// return noModifications
// }
override fun after(ifStatement: IfStatement, parent: Node): Iterable<IAstModification> {
// remove empty if statements
if(ifStatement.truepart.isEmpty() && ifStatement.elsepart.isEmpty())

View File

@ -412,9 +412,9 @@ internal class StatementReorderer(val program: Program,
}
return listOf(IAstModification.ReplaceNode(call, scope, parent))
} else if(!options.compTarget.asmsubArgsHaveRegisterClobberRisk(call.args)) {
// no register clobber risk, let the asmgen assign values to the registers directly.
// this is more efficient than first evaluating them to the stack
// TODO but what about complex expressions?
// No register clobber risk, let the asmgen assign values to the registers directly.
// this is more efficient than first evaluating them to the stack.
// As complex expressions will be flagged as a clobber-risk, these will be simplified below.
return noModifications
} else {
// clobber risk; evaluate the arguments on the CPU stack first (in reverse order)...

View File

@ -1,40 +1,19 @@
%import textio
%import string
%import test_stack
main {
ubyte[23] savedata
ubyte[17] cargohold = 0
uword filenameptr = $c000
sub start() {
test_stack.test()
save(8, "wob", 0, 10)
ubyte x1 = 10
ubyte x2 = 20
ubyte x3 = 30
uword @shared uw
ubyte @shared ub
word @shared ww
byte @shared bb
x1 += x2+x3 ; TODO WHY SLOW EVAL????
x1 += x2-x3 ; TODO WHY SLOW EVAL????
push(ub+1)
pop(ub)
txt.print_ub(ub)
txt.nl()
pushw(32767)
popw(uw)
txt.print_uw(uw)
txt.nl()
single(ub+1)
; uw=10000
; routines(44,uw+123)
; routines2(44,uw+123)
;
; routine(uw+123, 22,33, true, 44)
; routine2(uw+123, 22,33, true, 44)
txt.print_ub(x1)
test_stack.test()
@ -42,58 +21,4 @@ main {
}
}
sub save(ubyte drivenumber, uword filenameptr, uword address, uword size) {
c64.SETNAM(string.length(filenameptr), filenameptr)
}
sub single(ubyte num) {
num++
}
sub routine(uword num, ubyte a1, ubyte a2, ubyte switch, byte a3) {
txt.print_uw(num)
txt.spc()
txt.print_ub(a1)
txt.spc()
txt.print_ub(a2)
txt.spc()
txt.print_ub(switch)
txt.spc()
txt.print_b(a3)
txt.nl()
}
sub routines(ubyte bb, uword num) {
txt.print_ub(bb)
txt.spc()
txt.print_uw(num)
txt.nl()
}
asmsub routine2(uword num @AY, ubyte a1 @R1, ubyte a2 @R0, ubyte switch @Pc, ubyte a3 @X) {
%asm {{
sta routine.num
sty routine.num+1
lda #0
adc #0
sta routine.switch
lda cx16.r0
sta routine.a2
lda cx16.r1
sta routine.a1
stx routine.a3
jmp routine
}}
}
asmsub routines2(ubyte bb @X, uword num @AY) {
%asm {{
sta routines.num
sty routines.num+1
stx routines.bb
jmp routines
}}
}
}