tweaked repeat

compiler/src/prog8/compiler/target/c64/codegen/AsmGen.kt

@@ -966,12 +966,10 @@ internal class AsmGen(private val program: Program,
                 val name = asmVariableName(stmt.iterations as IdentifierReference)
                 when(vardecl.datatype) {
                     DataType.UBYTE, DataType.BYTE -> {
-                        out("  lda  $name")
+                        repeatByteCountVar(name, repeatLabel, endLabel, stmt.body)
-                        repeatByteCountInA(null, repeatLabel, endLabel, stmt.body)
                     }
                     DataType.UWORD, DataType.WORD -> {
-                        out("  lda  $name |  ldy  $name+1")
+                        repeatWordCountVar(name, repeatLabel, endLabel, stmt.body)
-                        repeatWordCountInAY(null, repeatLabel, endLabel, stmt.body)
                     }
                     else -> throw AssemblyError("invalid loop variable datatype $vardecl")
                 }
@@ -1001,6 +999,7 @@ internal class AsmGen(private val program: Program,
         if(constIterations==0)
             return
         // note: A/Y must have been loaded with the number of iterations already!
+        // TODO can be even more optimized by iterating over pages
         val counterVar = makeLabel("repeatcounter")
         out("""
                 sta  $counterVar
@@ -1035,22 +1034,54 @@ $counterVar    .word  0""")
         val counterVar = makeLabel("repeatcounter")
         if(constIterations==null)
             out("  beq  $endLabel")
-        out("""
+        out("  sta  $counterVar")
-            sta  $counterVar
+        out(repeatLabel)
-$repeatLabel""")
         translate(body)
         out("""
              dec  $counterVar
              bne  $repeatLabel
-             beq  $endLabel""")
+             beq  $endLabel  
-        if(constIterations!=null && constIterations>=16 && zeropage.available() > 0) {
-            // allocate count var on ZP
-            val zpAddr = zeropage.allocate(counterVar, DataType.UBYTE, body.position, errors)
-            out("""$counterVar = $zpAddr  ; auto zp UBYTE""")
-        } else {
-            out("""
 $counterVar    .byte  0""")
-        }
+        out(endLabel)
+    }
+
+    private fun repeatByteCountVar(repeatCountVar: String, repeatLabel: String, endLabel: String, body: AnonymousScope) {
+        // note: cannot use original counter variable because it should retain its original value
+        val counterVar = makeLabel("repeatcounter")
+        out("  lda  $repeatCountVar |  beq  $endLabel |  sta  $counterVar")
+        out(repeatLabel)
+        translate(body)
+        out("  dec  $counterVar |  bne  $repeatLabel")
+        // inline countervar:
+        out("""
+                beq  $endLabel  
+$counterVar    .byte  0""")
+        out(endLabel)
+    }
+
+    private fun repeatWordCountVar(repeatCountVar: String, repeatLabel: String, endLabel: String, body: AnonymousScope) {
+        // TODO can be even more optimized by iterating over pages
+        // note: cannot use original counter variable because it should retain its original value
+        val counterVar = makeLabel("repeatcounter")
+        out("""
+            lda  $repeatCountVar
+            sta  $counterVar
+            ora  $repeatCountVar+1
+            beq  $endLabel
+            lda  $repeatCountVar+1
+            sta  $counterVar+1""")
+        out(repeatLabel)
+        translate(body)
+        out("""
+            lda  $counterVar
+            bne  +
+            dec  $counterVar+1
++           dec  $counterVar
+            lda  $counterVar
+            ora  $counterVar+1
+            bne  $repeatLabel
+            beq  $endLabel  
+$counterVar    .word  0""")
         out(endLabel)
     }
 

docs/source/todo.rst

@@ -2,15 +2,13 @@
 TODO
 ====
 
-- add any2(), all2(), max2(), min2(), reverse2(), sum2(), sort2() that take (array, startindex, length) arguments
 - optimize for loop iterations better to allow proper inx, cpx #value, bne loop  instructions  (like repeat loop)
-- why is there a beq  _prog8_label_2_repeatend  at the end of repeat loops? seems unused
 - optimize swap of two memread values with index, using the same pointer expression/variable, like swap(@(ptr+1), @(ptr+2))
 - implement the linked_list millfork benchmark
-- use the 65c02 bit clear/set/test instructions for single-bit operations
 
 - implement highres 4 color mode in gfx2
 - make a retro Amiga Workbench "simulator" using that new gfx mode
+- use the 65c02 bit clear/set/test instructions for single-bit operations
 - add a flood fill routine to gfx2
 - can we get rid of the --longOptionName command line options and only keep the short versions? https://github.com/Kotlin/kotlinx-cli/issues/50
 - add a f_seek() routine for the Cx16 that uses its seek dos api?

examples/test.p8

@@ -5,6 +5,12 @@ main {
 
 
     sub start() {
-        txt.print("hello\n")
+        uword xx
+        uword iter = 256
+        repeat iter {
+            xx++
+        }
+
+        txt.print_uw(xx)
     }
 }

syntax-files/IDEA/Prog8.xml

@@ -11,7 +11,7 @@
       <option name="HAS_PARENS" value="true" />
       <option name="HAS_STRING_ESCAPES" value="true" />
     </options>
-    <keywords keywords="&amp;;-&gt;;@;\$;and;as;asmsub;break;clobbers;continue;do;downto;else;false;for;goto;if;if_cc;if_cs;if_eq;if_mi;if_ne;if_neg;if_nz;if_pl;if_pos;if_vc;if_vs;if_z;in;inline;not;or;repeat;return;romsub;step;sub;to;true;until;when;while;xor;~" ignore_case="false" />
+    <keywords keywords="&amp;;-&gt;;@;\$;and;as;asmsub;break;clobbers;do;downto;else;false;for;goto;if;if_cc;if_cs;if_eq;if_mi;if_ne;if_neg;if_nz;if_pl;if_pos;if_vc;if_vs;if_z;in;inline;not;or;repeat;return;romsub;step;sub;to;true;until;when;while;xor;~" ignore_case="false" />
     <keywords2 keywords="%address;%asm;%asmbinary;%asminclude;%breakpoint;%import;%launcher;%option;%output;%target;%zeropage;%zpreserved" />
     <keywords3 keywords="byte;const;float;str;struct;ubyte;uword;void;word;zp" />
     <keywords4 keywords="abs;acos;all;any;asin;atan;avg;ceil;cos;cos16;cos16u;cos8;cos8u;deg;floor;len;ln;log2;lsb;lsl;lsr;max;memory;min;mkword;msb;offsetof;rad;reverse;rnd;rndf;rndw;rol;rol2;ror;ror2;round;sgn;sin;sin16;sin16u;sin8;sin8u;sizeof;sort;sqrt;sqrt16;sum;swap;tan" />