fixed stack/branch bug in for loop

compiler/src/prog8/compiler/Compiler.kt

@@ -2067,13 +2067,13 @@ private class StatementTranslator(private val prog: IntermediateProgram,
                 val opcode = opcodePushvar(targetStatement!!.datatype)
                 prog.instr(opcode, callLabel = targetStatement.scopedname)
             }
-            val branch = BranchStatement(
-                    BranchCondition.NZ,
-                    AnonymousScope(mutableListOf(Jump(null, null, loopLabel, range.position)), range.position),
-                    AnonymousScope(mutableListOf(), range.position),
-                    range.position)
-            branch.linkParents(body)
-            translate(branch)
+            // TODO: optimize this to use a compare + branch opcode somehow?
+            val conditionJumpOpcode = when(targetStatement!!.datatype) {
+                DataType.UBYTE, DataType.BYTE -> Opcode.JNZ
+                DataType.UWORD, DataType.WORD -> Opcode.JNZW
+                else -> throw CompilerException("invalid loopvar datatype (expected byte or word) $lvTarget")
+            }
+            prog.instr(conditionJumpOpcode, callLabel = loopLabel)
         }
 
         when (literalStepValue) {

examples/cube3d-sprites.p8

@@ -91,7 +91,7 @@
             c64.PLOT(0,0,0)
             c64scr.print("3d cube! (sprites) ")
             c64scr.print_ub(c64.TIME_LO)
-            c64scr.print(" jiffies/frame")
+            c64scr.print(" jiffies/frame ")
         }
     }
 
@@ -133,7 +133,26 @@
     sub position_sprites() {
 
         ; set each of the 8 sprites to the correct vertex of the cube
-        ; @todo sort vertices to sprite order so the back/front order is correct as well
+
+        ; first sort vertices to sprite order so the back/front order is correct as well
+        ; (chose to do a simple bubble sort it's only 8 items to sort)
+        for ubyte sorti in 6 to 0 step -1 {
+            for ubyte i1 in 0 to sorti {
+                ubyte i2 = i1+1
+                if(rotatedz[i1] > rotatedz[i2]) {
+                    ; @todo use a swap() builtin function?
+                    word temp = rotatedx[i1]
+                    rotatedx[i1] = rotatedx[i2]
+                    rotatedx[i2] = temp
+                    temp = rotatedy[i1]
+                    rotatedy[i1] = rotatedy[i2]
+                    rotatedy[i2] = temp
+                    temp = rotatedz[i1]
+                    rotatedz[i1] = rotatedz[i2]
+                    rotatedz[i2] = temp
+                }
+            }
+        }
 
         for ubyte i in 0 to 7 {
             word zc = rotatedz[i]

examples/test.p8

@@ -5,14 +5,58 @@
 
     sub start()  {
 
-        str s = "hello"
-        byte[4] ba
+        word[8] rotatedx = [11,33,55,77,22,44,66,88]
+        word[8] rotatedy = [11,33,55,77,22,44,66,88]
+        word[8] rotatedz = [1,3,-5,7,2,4,-6,8]
+
+        printarray()
+
+        c64scr.print_ub(X)
+        c64.CHROUT('\n')
+
+        for ubyte sorti in 6 to 0 step -1 {
+            for ubyte i1 in 0 to sorti {
+                ubyte i2=i1+1
+                if(rotatedz[i2]>rotatedz[i1]) {
+                    word t = rotatedx[i1]
+                    rotatedx[i1] = rotatedx[i2]
+                    rotatedx[i2] = t
+                    t = rotatedy[i1]
+                    rotatedy[i1] = rotatedy[i2]
+                    rotatedy[i2] = t
+                    t = rotatedz[i1]
+                    rotatedz[i1] = rotatedz[i2]
+                    rotatedz[i2] = t
+                }
+            }
+        }
+
+        c64scr.print_ub(X)
+        c64.CHROUT('\n')
+
+        printarray()
 
 
-        float x = 33+s
-        x = 33+ba
-
+        sub printarray() {
+            for word a in rotatedx {
+                c64scr.print_w(a)
+                c64.CHROUT(',')
+            }
+            c64.CHROUT('\n')
+            for word a in rotatedy {
+                c64scr.print_w(a)
+                c64.CHROUT(',')
+            }
+            c64.CHROUT('\n')
+            for word a in rotatedz {
+                c64scr.print_w(a)
+                c64.CHROUT(',')
+            }
+            c64.CHROUT('\n')
+            c64.CHROUT('\n')
+        }
     }
 
+
 }