From 203ec5fa46f883885b7e66526f18770aa1717785 Mon Sep 17 00:00:00 2001
From: Irmen de Jong <irmen@razorvine.net>
Date: Sat, 14 Oct 2023 07:57:36 +0200
Subject: [PATCH] implement taking address of array var with variable index

---
 .../cpu6502/assignment/AssignmentAsmGen.kt    | 25 ++++++++++++++--
 docs/source/todo.rst                          |  3 +-
 examples/test.p8                              | 29 ++++++++++++++-----
 3 files changed, 45 insertions(+), 12 deletions(-)

diff --git a/codeGenCpu6502/src/prog8/codegen/cpu6502/assignment/AssignmentAsmGen.kt b/codeGenCpu6502/src/prog8/codegen/cpu6502/assignment/AssignmentAsmGen.kt
index f2ed04c63..f3866622f 100644
--- a/codeGenCpu6502/src/prog8/codegen/cpu6502/assignment/AssignmentAsmGen.kt
+++ b/codeGenCpu6502/src/prog8/codegen/cpu6502/assignment/AssignmentAsmGen.kt
@@ -2210,7 +2210,26 @@ internal class AssignmentAsmGen(private val program: PtProgram,
                     program.memsizer.memorySize(arrayDt!!, constIndex)  // add arrayIndexExpr * elementsize  to the address of the array variable.
             } else {
                 val eltSize = program.memsizer.memorySize(ArrayToElementTypes.getValue(arrayDt!!))
-                TODO("address-of array element $sourceName size $eltSize with non-const index at ${target.position}")
+                assignExpressionToVariable(arrayIndexExpr, "P8ZP_SCRATCH_W1", DataType.UWORD)
+                when(eltSize) {
+                    1 -> {}
+                    2 -> {
+                        if(arrayDt !in SplitWordArrayTypes)
+                            asmgen.out("  asl  P8ZP_SCRATCH_W1 |  rol  P8ZP_SCRATCH_W1+1")
+                    }
+                    else -> TODO("address-of array element $sourceName size $eltSize with non-const index at ${target.position}")
+                }
+                asmgen.out("""
+                    lda  #<$sourceName
+                    clc
+                    adc  P8ZP_SCRATCH_W1
+                    tax
+                    lda  #>$sourceName
+                    adc  P8ZP_SCRATCH_W1+1
+                    tay
+                    txa""")
+                assignRegisterpairWord(target, RegisterOrPair.AY)
+                return
             }
         } else 0
 
@@ -2286,9 +2305,9 @@ internal class AssignmentAsmGen(private val program: PtProgram,
                 if(sourceDt==DataType.UBYTE) {
                     asmgen.out("  lda  $sourceName |  sta  ${target.asmVarname}")
                     if(asmgen.isTargetCpu(CpuType.CPU65c02))
-                        asmgen.out("  stz  ${target.asmVarname}")
+                        asmgen.out("  stz  ${target.asmVarname}+1")
                     else
-                        asmgen.out("  lda  #0 |  sta  ${target.asmVarname}")
+                        asmgen.out("  lda  #0 |  sta  ${target.asmVarname}+1")
                 }
                 else
                     asmgen.out("""
diff --git a/docs/source/todo.rst b/docs/source/todo.rst
index 31ed498a3..dcd61635a 100644
--- a/docs/source/todo.rst
+++ b/docs/source/todo.rst
@@ -1,9 +1,8 @@
 TODO
 ====
 
-- fix TODO  "address-of array element" in assignAddressOf()
-
 - gfx2: use vera auto in/decrement in the flood fill routine
+- add an option to inject an actual instruction (STP on 65c02, BRK on 6502) for breakpoints, instead of only listing them in the vice symbol file.
 
 - [on branch: shortcircuit] investigate McCarthy evaluation again? this may also reduce code size perhaps for things like if a>4 or a<2 ....
 - [on branch: ir-less-branch-opcodes] IR: reduce the number of branch instructions such as BEQ, BEQR, etc (gradually), replace with CMP(I) + status branch instruction
diff --git a/examples/test.p8 b/examples/test.p8
index 8d3b96799..de569c8e9 100644
--- a/examples/test.p8
+++ b/examples/test.p8
@@ -3,6 +3,7 @@
 
 main {
     sub start() {
+        ubyte[] b_array = [11,22,33,44]
         uword[] w_array = [1111,2222,3333,4444]
         uword[] @split split_array = [1111,2222,3333,4444]
         ubyte index = 2
@@ -13,21 +14,35 @@ main {
 
         uword pstep = w_array[index]
         uword psteps = split_array[index]
-        ;; uword @zp ptr = &w_array[index]
 
         txt.print_uw(pstep)
         txt.nl()
         txt.print_uw(psteps)
         txt.nl()
-;        txt.print_uw(peekw(ptr))
-;        txt.nl()
 
-        w_array[index] += 10
-        split_array[index] += 10
-        txt.print_uw(w_array[index])
+        uword @zp ptr = &w_array[index]
+        txt.print_uw(peekw(ptr))
         txt.nl()
-        txt.print_uw(split_array[index])
+        txt.print_uwhex(&w_array, true)
+        txt.spc()
+        txt.print_uwhex(ptr, true)
         txt.nl()
+        ptr = &split_array
+        txt.print_uw(peekw(ptr))
+        txt.nl()
+        txt.print_uwhex(&w_array, true)
+        txt.spc()
+        txt.print_uwhex(ptr, true)
+        txt.nl()
+
+        ptr = &b_array[index]
+        txt.print_ub(peek(ptr))
+        txt.nl()
+        txt.print_uwhex(&b_array, true)
+        txt.spc()
+        txt.print_uwhex(ptr, true)
+        txt.nl()
+
     }
 }