From 4661cba97403b68f6ec7f2b0400283d9f63ac710 Mon Sep 17 00:00:00 2001
From: Irmen de Jong <irmen@razorvine.net>
Date: Mon, 29 Jul 2019 22:47:04 +0200
Subject: [PATCH] asm for when statements added

---
 .../src/prog8/ast/processing/AstChecker.kt    |  3 ++
 .../ast/processing/StatementReorderer.kt      | 21 ----------
 .../compiler/target/c64/codegen2/AsmGen2.kt   | 39 ++++++++++++++++++-
 examples/test.p8                              |  1 +
 4 files changed, 42 insertions(+), 22 deletions(-)

diff --git a/compiler/src/prog8/ast/processing/AstChecker.kt b/compiler/src/prog8/ast/processing/AstChecker.kt
index 17674df63..9585ee67a 100644
--- a/compiler/src/prog8/ast/processing/AstChecker.kt
+++ b/compiler/src/prog8/ast/processing/AstChecker.kt
@@ -955,6 +955,9 @@ internal class AstChecker(private val program: Program,
         tally.filter { it.value>1 }.forEach {
             checkResult.add(SyntaxError("choice value occurs multiple times", it.key.position))
         }
+        if(whenStatement.choices.isEmpty())
+            checkResult.add(SyntaxError("empty when statement", whenStatement.position))
+
         super.visit(whenStatement)
     }
 
diff --git a/compiler/src/prog8/ast/processing/StatementReorderer.kt b/compiler/src/prog8/ast/processing/StatementReorderer.kt
index 6955cd2c4..20d5ea510 100644
--- a/compiler/src/prog8/ast/processing/StatementReorderer.kt
+++ b/compiler/src/prog8/ast/processing/StatementReorderer.kt
@@ -329,27 +329,6 @@ internal class StatementReorderer(private val program: Program): IAstModifyingVi
         return super.visit(typecast)
     }
 
-    override fun visit(whenStatement: WhenStatement): Statement {
-        // make sure all choices are just for one single value
-        val choices = whenStatement.choices.toList()
-        for(choice in choices) {
-            val choiceValues = choice.values
-            if(choiceValues==null || choiceValues.size==1)
-                continue
-            for(v in choiceValues) {
-                val newchoice=WhenChoice(listOf(v), choice.statements, choice.position)
-                newchoice.parent = choice.parent
-                whenStatement.choices.add(newchoice)
-            }
-            whenStatement.choices.remove(choice)
-        }
-
-        // sort the choices in low-to-high value order (nulls last)
-        whenStatement.choices
-                .sortWith(compareBy<WhenChoice, Int?>(nullsLast(), {it.values?.single()?.constValue(program)?.number?.toInt()}))
-        return super.visit(whenStatement)
-    }
-
     override fun visit(memread: DirectMemoryRead): Expression {
         // make sure the memory address is an uword
         val dt = memread.addressExpression.inferType(program)
diff --git a/compiler/src/prog8/compiler/target/c64/codegen2/AsmGen2.kt b/compiler/src/prog8/compiler/target/c64/codegen2/AsmGen2.kt
index 82f80a460..b16f3a47a 100644
--- a/compiler/src/prog8/compiler/target/c64/codegen2/AsmGen2.kt
+++ b/compiler/src/prog8/compiler/target/c64/codegen2/AsmGen2.kt
@@ -837,7 +837,44 @@ internal class AsmGen2(val program: Program,
     }
 
     private fun translate(stmt: WhenStatement) {
-        TODO("when $stmt")
+        translateExpression(stmt.condition)
+        val endLabel = makeLabel("choice_end")
+        val choiceBlocks = mutableListOf<Pair<String, AnonymousScope>>()
+        val conditionDt = stmt.condition.inferType(program)!!
+        if(conditionDt in ByteDatatypes)
+            out("  inx |  lda  $ESTACK_LO_HEX,x")
+        else
+            out("  inx |  lda  $ESTACK_LO_HEX,x |  ldy  $ESTACK_HI_HEX,x")
+        for(choice in stmt.choices) {
+            val choiceLabel = makeLabel("choice")
+            if(choice.values==null) {
+                // the else choice
+                translate(choice.statements)
+                out("  jmp  $endLabel")
+            } else {
+                choiceBlocks.add(Pair(choiceLabel, choice.statements))
+                for (cv in choice.values!!) {
+                    val value = (cv as NumericLiteralValue).number.toInt()
+                    if(conditionDt in ByteDatatypes) {
+                        out("  cmp  #${value.toHex()} |  beq  $choiceLabel")
+                    } else {
+                        out("""
+                            cmp  #<${value.toHex()}
+                            bne  +
+                            cpy  #>${value.toHex()}
+                            beq  $choiceLabel
++                            
+                            """)
+                    }
+                }
+            }
+        }
+        for(choiceBlock in choiceBlocks) {
+            out(choiceBlock.first)
+            translate(choiceBlock.second)
+            out("  jmp  $endLabel")
+        }
+        out(endLabel)
     }
 
     private fun translate(stmt: Label) {
diff --git a/examples/test.p8 b/examples/test.p8
index 5ac4fea35..9ca864974 100644
--- a/examples/test.p8
+++ b/examples/test.p8
@@ -59,6 +59,7 @@
                 9999 -> c64scr.print("ninetynine99")
                 else -> c64scr.print("don't know")
             }
+
             c64.CHROUT('\n')
         }