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for loop generates working code for the most often occurring loop scenarios

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This commit is contained in:
Irmen de Jong 2018-09-22 02:38:53 +02:00
parent f84e06bdeb
commit 4174d49fb3
2 changed files with 111 additions and 59 deletions
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78
compiler/examples/test.p8
View File

@ -8,38 +8,62 @@ sub start() -> () {
byte from = 0
byte last = 5
if (i>last) {
_vm_write_num(100)
word iw
word fromw = 0
word lastw = 5
for i in 10 to 1 step -1 {
_vm_write_num(i)
_vm_write_char($8d)
}
_vm_write_char($8d)
_vm_write_char($8d)
for i in 10 to 0 step -1 {
_vm_write_num(i)
_vm_write_char($8d)
}
_vm_write_char($8d)
_vm_write_char($8d)
for i in from to last {
_vm_write_num(i)
_vm_write_char($8d)
}
_vm_write_char($8d)
_vm_write_char($8d)
from=250
last=255
for i in from to last {
_vm_write_num(i)
_vm_write_char($8d)
}
_vm_write_char($8d)
_vm_write_char($8d)
fromw=65530
lastw=65535
for iw in fromw to lastw {
_vm_write_num(iw)
_vm_write_char($8d)
}
_vm_write_char($8d)
_vm_write_char($8d)
; for i in from to last {
; _vm_write_num(i)
; _vm_write_char($8d)
; }
; _vm_write_char($8d)
; _vm_write_char($8d)
from = 5
last = 1
; from=250
; last=255
; for i in from to last {
; _vm_write_num(i)
; _vm_write_char($8d)
; }
; _vm_write_char($8d)
; _vm_write_char($8d)
;
;
; from = 8
; last = 0
;
; for i in from to last step -1 {
; _vm_write_num(i)
; _vm_write_char($8d)
; }
; _vm_write_char($8d)
; _vm_write_char($8d)
fromw = 1
lastw = 5
for iw in fromw to lastw step 1 { ;@todo last 0
_vm_write_num(iw)
_vm_write_char($8d)
}
_vm_write_char($8d)
_vm_write_char($8d)
}
}

92
compiler/src/prog8/compiler/Compiler.kt
View File

@ -212,6 +212,9 @@ private class StatementTranslator(private val stackvmProg: StackVmProgram, priva
* other_stuff ;; optional
* _stmt_999_end:
* nop
*
* @todo generate more efficient bytecode for the form with just jumps: if_xx goto .. [else goto ..] ?
* -> this should translate into just a single branch opcode per goto
*/
stackvmProg.line(branch.position)
val labelElse = makeLabel("else")
@ -258,17 +261,18 @@ private class StatementTranslator(private val stackvmProg: StackVmProgram, priva
*
* or when there is no else block:
* <condition-expression evaluation>
* BNZ _stmt_999_end
* BZ _stmt_999_end
* stuff
* _stmt_999_end:
* nop
*
* @todo generate more efficient bytecode for the form with just jumps: if(..) goto .. [else goto ..]
*/
stackvmProg.line(stmt.position)
translate(stmt.condition)
val labelEnd = makeLabel("end")
if(stmt.elsepart.isEmpty()) {
stackvmProg.instr(Opcode.BNZ, callLabel = labelEnd)
stackvmProg.instr(Opcode.BZ, callLabel = labelEnd)
translate(stmt.statements)
stackvmProg.label(labelEnd)
} else {
@ -319,7 +323,7 @@ private class StatementTranslator(private val stackvmProg: StackVmProgram, priva
}
}
is RangeExpr -> {
TODO("TRANSLATE range $expr") // todo
TODO("TRANSLATE range $expr")
}
else -> {
val lv = expr.constValue(namespace) ?: throw CompilerException("constant expression required, not $expr")
@ -540,7 +544,7 @@ private class StatementTranslator(private val stackvmProg: StackVmProgram, priva
else if (range.count()==1)
throw CompilerException("loop over just 1 value should have been optimized away")
if((range.last-range.first) % range.step != 0)
throw CompilerException("range first and last must be inclusive")
throw CompilerException("range first and last must be exactly inclusive")
when (loopVarDt) {
DataType.BYTE -> {
if (range.first < 0 || range.first > 255 || range.last < 0 || range.last > 255)
@ -660,9 +664,17 @@ private class StatementTranslator(private val stackvmProg: StackVmProgram, priva
* ..continue statement: goto continue
* ..
* continue:
* LV ++ / LV-- (if step =1 or step=-1)
* LV += step (otherwise)
* goto loop
*
* (if we know step is a constant:)
* step == 1 ->
* LV++
* if_nz goto loop ;; acts as overflow check
* step == -1 ->
* LV--
* @todo some condition to check for not overflow , jump to loop
* (not constant or other step:
* LV += step ; @todo implement overflow on the appropriate arithmetic operations
* if_vc goto loop ;; not overflowed
* break:
* nop
*/
@ -687,6 +699,7 @@ private class StatementTranslator(private val stackvmProg: StackVmProgram, priva
stackvmProg.label(loopLabel)
if(literalStepValue!=null) {
// Step is a constant. We can optimize some stuff!
val loopVar =
if(varname!=null)
IdentifierReference(varname, range.position)
@ -708,34 +721,49 @@ private class StatementTranslator(private val stackvmProg: StackVmProgram, priva
ifstmt.linkParents(range.parent)
translate(ifstmt)
} else {
// generate code for the whole if statement
TODO("code for non-constant step comparison")
// Step is a variable. We can't optimize anything...
TODO("code for non-constant step comparison of LV")
}
stackvmProg.label("body_goes_here") // todo weg
translate(body)
stackvmProg.label(continueLabel)
val lvTarget = makeAssignmentTarget()
lvTarget.linkParents(range.parent)
val targetStatement: VarDecl? =
if(lvTarget.identifier!=null) {
lvTarget.identifier.targetStatement(namespace) as VarDecl
} else {
null
}
// translate(body)
// stackvmProg.label(continueLabel)
// when (literalStepValue) {
// 1 -> {
// // LV++
// val postIncr = PostIncrDecr(makeAssignmentTarget(), "++", range.position)
// postIncr.linkParents(range.parent)
// translate(postIncr)
// }
// -1 -> {
// // LV--
// val postIncr = PostIncrDecr(makeAssignmentTarget(), "--", range.position)
// postIncr.linkParents(range.parent)
// translate(postIncr)
// }
// else -> {
// // LV += step
// val addAssignment = Assignment(makeAssignmentTarget(), "+=", range.step, range.position)
// addAssignment.linkParents(range.parent)
// translate(addAssignment)
// }
// }
when (literalStepValue) {
1 -> {
// LV++
val postIncr = PostIncrDecr(lvTarget, "++", range.position)
postIncr.linkParents(range.parent)
translate(postIncr)
if(lvTarget.register!=null)
stackvmProg.instr(Opcode.PUSH_VAR, Value(DataType.STR, null, stringvalue=lvTarget.register.toString()))
else
stackvmProg.instr(Opcode.PUSH_VAR, Value(DataType.STR, null, stringvalue=targetStatement!!.scopedname))
val branch = BranchStatement(
BranchCondition.NZ,
listOf(Jump(null, null, loopLabel, range.position)),
emptyList(), range.position)
branch.linkParents(range.parent)
translate(branch)
}
-1 -> {
// LV--
val postIncr = PostIncrDecr(makeAssignmentTarget(), "--", range.position)
postIncr.linkParents(range.parent)
translate(postIncr)
TODO("signed numbers and/or special condition still needed for decreasing for loop. Try increasing loop and/or constant loop values instead? At: ${range.position}")
}
else -> {
TODO("non-literal-const or other-than-one step increment code At: ${range.position}")
}
}
stackvmProg.label(breakLabel)
stackvmProg.instr(Opcode.NOP)