From 0d7b14e2d891b1b0d9084b8d7ab69675024a2b27 Mon Sep 17 00:00:00 2001
From: Irmen de Jong <irmen@razorvine.net>
Date: Sun, 23 Oct 2022 11:57:23 +0200
Subject: [PATCH] fix crash when assigning certain memory read to word
 variable. Fixes #82

---
 .../cpu6502/assignment/AssignmentAsmGen.kt    | 19 ++++++-------------
 compiler/test/TestTypecasts.kt                | 15 +++++++++++++++
 2 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/codeGenCpu6502/src/prog8/codegen/cpu6502/assignment/AssignmentAsmGen.kt b/codeGenCpu6502/src/prog8/codegen/cpu6502/assignment/AssignmentAsmGen.kt
index 96a8ae60e..45a87c6f5 100644
--- a/codeGenCpu6502/src/prog8/codegen/cpu6502/assignment/AssignmentAsmGen.kt
+++ b/codeGenCpu6502/src/prog8/codegen/cpu6502/assignment/AssignmentAsmGen.kt
@@ -852,7 +852,8 @@ internal class AssignmentAsmGen(private val program: Program,
                     fun assignViaExprEval(addressExpression: Expression) {
                         asmgen.assignExpressionToVariable(addressExpression, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
                         asmgen.loadAFromZpPointerVar("P8ZP_SCRATCH_W2")
-                        assignRegisterByte(target, CpuRegister.A)
+                        asmgen.out("  ldy  #0")
+                        assignRegisterpairWord(target, RegisterOrPair.AY)
                     }
 
                     when (value.addressExpression) {
@@ -1972,18 +1973,10 @@ internal class AssignmentAsmGen(private val program: Program,
     }
 
     internal fun assignRegisterByte(target: AsmAssignTarget, register: CpuRegister) {
-        // we make an exception in the type check for assigning something to a cx16 virtual register, or a register pair
-        // these will be correctly typecasted from a byte to a word value
-        if(target.register !in Cx16VirtualRegisters &&
-            target.register!=RegisterOrPair.AX && target.register!=RegisterOrPair.AY && target.register!=RegisterOrPair.XY) {
-            if(target.kind== TargetStorageKind.VARIABLE) {
-                val parts = target.asmVarname.split('.')
-                if (parts.size != 2 || parts[0] != "cx16")
-                    require(target.datatype in ByteDatatypes)
-            } else {
-                require(target.datatype in ByteDatatypes)
-            }
-        }
+        // we make an exception in the type check for assigning something to a register pair AX, AY or XY
+        // these will be correctly typecasted from a byte to a word value here
+        if(target.register !in setOf(RegisterOrPair.AX, RegisterOrPair.AY, RegisterOrPair.XY))
+            require(target.datatype in ByteDatatypes)
 
         when(target.kind) {
             TargetStorageKind.VARIABLE -> {
diff --git a/compiler/test/TestTypecasts.kt b/compiler/test/TestTypecasts.kt
index 939a55e6b..32d8ccc42 100644
--- a/compiler/test/TestTypecasts.kt
+++ b/compiler/test/TestTypecasts.kt
@@ -919,4 +919,19 @@ main  {
             }"""
         compileText(C64Target(), true, text, writeAssembly = true) shouldNotBe null
     }
+
+    test("memory reads byte into word variable") {
+        val text = """
+            main {
+                sub start() {
+                    uword @shared ww
+                    uword address = $1000
+                    ww = @(address+100)
+                    ww = @(address+1000)
+                    cx16.r0 = @(address+100)
+                    cx16.r0 = @(address+1000)
+                }
+            }"""
+        compileText(C64Target(), false, text, writeAssembly = true) shouldNotBe null
+    }
 })