Apple-2-SW/prog8
1
0
Fork 0
mirror of https://github.com/irmen/prog8.git synced 2024-11-26 11:49:22 +00:00
Code Issues Projects Releases Wiki Activity

slight optimization of repeat loop (> 256 iters) code generation on 65c02 cpu

Browse Source
This commit is contained in:
Irmen de Jong 2022-01-01 14:08:36 +01:00
parent 1e8d8e40a2
commit 9e90dbdde6
2 changed files with 65 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

77
codeGeneration/src/prog8/codegen/target/cpu6502/codegen/AsmGen.kt
View File

@ -1142,16 +1142,12 @@ class AsmGen(private val program: Program,
}
is NumericLiteralValue -> {
val iterations = (stmt.iterations as NumericLiteralValue).number.toInt()
if(iterations<0 || iterations > 65535)
throw AssemblyError("invalid number of iterations")
when {
iterations == 0 -> {}
iterations == 1 -> translate(stmt.body)
iterations<0 || iterations>65535 -> throw AssemblyError("invalid number of iterations")
iterations <= 256 -> repeatByteCount(iterations, stmt)
else -> {
out(" lda #<${iterations} | ldy #>${iterations}")
repeatWordCountInAY(iterations, endLabel, stmt)
}
else -> repeatWordCount(iterations, stmt)
}
}
is IdentifierReference -> {
@ -1164,7 +1160,7 @@ class AsmGen(private val program: Program,
}
DataType.UWORD, DataType.WORD -> {
assignVariableToRegister(name, RegisterOrPair.AY)
repeatWordCountInAY(null, endLabel, stmt)
repeatWordCountInAY(endLabel, stmt)
}
else -> throw AssemblyError("invalid loop variable datatype $vardecl")
}
@ -1180,7 +1176,7 @@ class AsmGen(private val program: Program,
}
in WordDatatypes -> {
assignExpressionToRegister(stmt.iterations!!, RegisterOrPair.AY)
repeatWordCountInAY(null, endLabel, stmt)
repeatWordCountInAY(endLabel, stmt)
}
else -> throw AssemblyError("invalid loop expression datatype $dt")
}
@ -1190,12 +1186,67 @@ class AsmGen(private val program: Program,
loopEndLabels.pop()
}
private fun repeatWordCountInAY(constIterations: Int?, endLabel: String, stmt: RepeatLoop) {
// note: A/Y must have been loaded with the number of iterations!
if(constIterations==0)
return
// no need to explicitly test for 0 iterations as this is done in the countdown logic below
private fun repeatWordCount(count: Int, stmt: RepeatLoop) {
require(count in 257..65535)
val repeatLabel = makeLabel("repeat")
if(isTargetCpu(CpuType.CPU65c02)) {
val counterVar = createRepeatCounterVar(DataType.UWORD, true, stmt)
if(counterVar!=null) {
out("""
lda #<$count
ldy #>$count
sta $counterVar
sty $counterVar+1
$repeatLabel""")
translate(stmt.body)
out("""
lda $counterVar
bne +
dec $counterVar+1
+ dec $counterVar
lda $counterVar
ora $counterVar+1
bne $repeatLabel""")
} else {
out("""
lda #<$count
ldy #>$count
$repeatLabel pha
phy""")
translate(stmt.body)
out("""
ply
pla
bne +
dey
+ dea
bne $repeatLabel
cpy #0
bne $repeatLabel""")
}
} else {
val counterVar = createRepeatCounterVar(DataType.UWORD, false, stmt)
out("""
lda #<$count
ldy #>$count
sta $counterVar
sty $counterVar+1
$repeatLabel""")
translate(stmt.body)
out("""
lda $counterVar
bne +
dec $counterVar+1
+ dec $counterVar
lda $counterVar
ora $counterVar+1
bne $repeatLabel""")
}
}
private fun repeatWordCountInAY(endLabel: String, stmt: RepeatLoop) {
// note: A/Y must have been loaded with the number of iterations!
// no need to explicitly test for 0 iterations as this is done in the countdown logic below
val repeatLabel = makeLabel("repeat")
val counterVar = createRepeatCounterVar(DataType.UWORD, false, stmt)!!
out("""

2
docs/source/todo.rst
View File

@ -3,7 +3,7 @@ TODO
For next compiler release (7.6)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
see if the 16 bit repeat code can be optimized on 65c02 a bit more as well, like the 8 bit
...
Need help with