From 88d5c68b329f6c441c39b5e73896fcc4e391d837 Mon Sep 17 00:00:00 2001
From: Irmen de Jong <irmen@razorvine.net>
Date: Thu, 20 Aug 2020 21:16:48 +0200
Subject: [PATCH] don't inc/dec a memory mapped register

---
 .../src/prog8/optimizer/StatementOptimizer.kt |  8 +-
 examples/test.p8                              | 79 ++++++++++---------
 2 files changed, 46 insertions(+), 41 deletions(-)

diff --git a/compiler/src/prog8/optimizer/StatementOptimizer.kt b/compiler/src/prog8/optimizer/StatementOptimizer.kt
index 7f6918f86..be6794d97 100644
--- a/compiler/src/prog8/optimizer/StatementOptimizer.kt
+++ b/compiler/src/prog8/optimizer/StatementOptimizer.kt
@@ -405,8 +405,8 @@ internal class StatementOptimizer(private val program: Program,
                         if (cv == 0.0) {
                             return listOf(IAstModification.Remove(assignment, parent))
                         } else if (targetDt in IntegerDatatypes && floor(cv) == cv) {
-                            if ((vardeclDt == VarDeclType.MEMORY && cv in 1.0..3.0) || (vardeclDt != VarDeclType.MEMORY && cv in 1.0..8.0)) {
-                                // replace by several INCs (a bit less when dealing with memory targets)
+                            if (vardeclDt != VarDeclType.MEMORY && cv in 1.0..4.0) {
+                                // replace by several INCs if it's not a memory address (inc on a memory mapped register doesn't work very well)
                                 val incs = AnonymousScope(mutableListOf(), assignment.position)
                                 repeat(cv.toInt()) {
                                     incs.statements.add(PostIncrDecr(assignment.target, "++", assignment.position))
@@ -419,8 +419,8 @@ internal class StatementOptimizer(private val program: Program,
                         if (cv == 0.0) {
                             return listOf(IAstModification.Remove(assignment, parent))
                         } else if (targetDt in IntegerDatatypes && floor(cv) == cv) {
-                            if ((vardeclDt == VarDeclType.MEMORY && cv in 1.0..3.0) || (vardeclDt != VarDeclType.MEMORY && cv in 1.0..8.0)) {
-                                // replace by several DECs (a bit less when dealing with memory targets)
+                            if (vardeclDt != VarDeclType.MEMORY && cv in 1.0..4.0) {
+                                // replace by several DECs if it's not a memory address (dec on a memory mapped register doesn't work very well)
                                 val decs = AnonymousScope(mutableListOf(), assignment.position)
                                 repeat(cv.toInt()) {
                                     decs.statements.add(PostIncrDecr(assignment.target, "--", assignment.position))
diff --git a/examples/test.p8 b/examples/test.p8
index 3b1924e06..9e8bb7570 100644
--- a/examples/test.p8
+++ b/examples/test.p8
@@ -7,44 +7,49 @@ main {
 
     sub start() {
 
-;        byte A = 99
-;        ubyte U = $18
-;        word B = 9999
-;        uword W = $18f0
-;
-;        c64scr.print_b(A)
-;        c64.CHROUT('\n')
-;        A = -A
-;        c64scr.print_b(A)
-;        c64.CHROUT('\n')
-;
-;        U = ~U
-;        c64scr.print_ubhex(U, true)
-;        c64.CHROUT('\n')
-;        U = not U
-;        c64scr.print_ubhex(U, true)
-;        c64.CHROUT('\n')
-;        U = not U
-;        c64scr.print_ubhex(U, true)
-;        c64.CHROUT('\n')
-;
-;        c64scr.print_w(B)
-;        c64.CHROUT('\n')
-;        B = -B
-;        c64scr.print_w(B)
-;        c64.CHROUT('\n')
-;
-;        W = ~W
-;        c64scr.print_uwhex(W, true)
-;        c64.CHROUT('\n')
-;        W = not W
-;        c64scr.print_uwhex(W, true)
-;        c64.CHROUT('\n')
-;        W = not W
-;        c64scr.print_uwhex(W, true)
-;        c64.CHROUT('\n')
+        byte A = 99
+        ubyte U = $18
+        word B = 9999
+        uword W = $18f0
 
-        uword W = 43210
+        c64scr.print_b(A)
+        c64.CHROUT('\n')
+        A = -A
+        c64scr.print_b(A)
+        c64.CHROUT('\n')
+
+        U = ~U
+        c64scr.print_ubhex(U, true)
+        c64.CHROUT('\n')
+        U = not U
+        c64scr.print_ubhex(U, true)
+        c64.CHROUT('\n')
+        U = not U
+        c64scr.print_ubhex(U, true)
+        c64.CHROUT('\n')
+
+        c64scr.print_w(B)
+        c64.CHROUT('\n')
+        B = -B
+        c64scr.print_w(B)
+        c64.CHROUT('\n')
+
+        W = ~W
+        c64scr.print_uwhex(W, true)
+        c64.CHROUT('\n')
+        W = not W
+        c64scr.print_uwhex(W, true)
+        c64.CHROUT('\n')
+        W = not W
+        c64scr.print_uwhex(W, true)
+        c64.CHROUT('\n')
+
+        ;@($d020) += @($d020)        ; TODO fix compiler hang
+
+        W += 3
+        @($d020) += 3
+
+        W = 43210
         W = W as ubyte
         c64scr.print_uw(W)
         c64.CHROUT('\n')