Add word (constant or memory loc) to pointer (unchecked for now).

HISTORY.markdown

@@ -5,6 +5,8 @@ History of SixtyPical
 ---
 
 *   Add word (constant or memory location) to word memory location.
+*   Add word to pointer (unchecked for now).
+*   Implementation: `--debug` shows some extra info during analysis.
 
 0.8
 ---

README.markdown

@@ -42,8 +42,6 @@ TODO
 
 ### Operations on 16 bit values
 
-Add word (constant or memory location) to pointer.  (Not necessarily range-checked yet though.)
-
 Compare word (constant or memory location) with memory location or pointer.  (Maybe?)
 
 And then write a little demo "game" where you can move a block around the screen with

src/sixtypical/analyzer.py

@@ -255,16 +255,22 @@ class Analyzer(object):
             context.assert_meaningful(src)
             context.set_written(dest)
         elif opcode == 'add':
+            context.assert_meaningful(src, dest, FLAG_C)
             if src.type == TYPE_BYTE:
                 self.assert_type(TYPE_BYTE, src, dest)
-                context.assert_meaningful(src, dest, FLAG_C)
                 context.set_written(dest, FLAG_Z, FLAG_N, FLAG_C, FLAG_V)
             else:
-                self.assert_type(TYPE_WORD, src, dest)
-                context.assert_meaningful(src, dest, FLAG_C)
-                context.set_written(dest, FLAG_Z, FLAG_N, FLAG_C, FLAG_V)
-                context.set_touched(REG_A)
-                context.set_unmeaningful(REG_A)
+                self.assert_type(TYPE_WORD, src)
+                if dest.type == TYPE_WORD:
+                    context.set_written(dest, FLAG_Z, FLAG_N, FLAG_C, FLAG_V)
+                    context.set_touched(REG_A)
+                    context.set_unmeaningful(REG_A)
+                elif isinstance(dest.type, PointerType):
+                    context.set_written(dest, FLAG_Z, FLAG_N, FLAG_C, FLAG_V)
+                    context.set_touched(REG_A)
+                    context.set_unmeaningful(REG_A)
+                else:
+                    self.assert_type(TYPE_WORD, dest)
         elif opcode == 'sub':
             self.assert_type(TYPE_BYTE, src, dest)
             context.assert_meaningful(src, dest, FLAG_C)

src/sixtypical/compiler.py

@@ -147,7 +147,7 @@ class Compiler(object):
                     self.emitter.emit(ADC(Immediate(Byte(src.value))))
                 else:
                     self.emitter.emit(ADC(Absolute(self.labels[src.name])))
-            elif isinstance(dest, LocationRef) and dest.type == TYPE_WORD and src.type == TYPE_WORD:
+            elif isinstance(dest, LocationRef) and src.type == TYPE_WORD and dest.type == TYPE_WORD:
                 if isinstance(src, ConstantRef):
                     dest_label = self.labels[dest.name]
                     self.emitter.emit(LDA(Absolute(dest_label)))
@@ -167,6 +167,26 @@ class Compiler(object):
                     self.emitter.emit(STA(Absolute(Offset(dest_label, 1))))
                 else:
                     raise UnsupportedOpcodeError(instr)
+            elif isinstance(dest, LocationRef) and src.type == TYPE_WORD and isinstance(dest.type, PointerType):
+                if isinstance(src, ConstantRef):
+                    dest_label = self.labels[dest.name]  # this. is. zero-page.
+                    self.emitter.emit(LDA(ZeroPage(dest_label)))
+                    self.emitter.emit(ADC(Immediate(Byte(src.low_byte()))))
+                    self.emitter.emit(STA(ZeroPage(dest_label)))
+                    self.emitter.emit(LDA(ZeroPage(Offset(dest_label, 1))))
+                    self.emitter.emit(ADC(Immediate(Byte(src.high_byte()))))
+                    self.emitter.emit(STA(ZeroPage(Offset(dest_label, 1))))
+                elif isinstance(src, LocationRef):
+                    src_label = self.labels[src.name]
+                    dest_label = self.labels[dest.name]  # this. is. zero-page.
+                    self.emitter.emit(LDA(ZeroPage(dest_label)))
+                    self.emitter.emit(ADC(Absolute(src_label)))
+                    self.emitter.emit(STA(ZeroPage(dest_label)))
+                    self.emitter.emit(LDA(ZeroPage(Offset(dest_label, 1))))
+                    self.emitter.emit(ADC(Absolute(Offset(src_label, 1))))
+                    self.emitter.emit(STA(ZeroPage(Offset(dest_label, 1))))
+                else:
+                    raise UnsupportedOpcodeError(instr)
             else:
                 raise UnsupportedOpcodeError(instr)
         elif opcode == 'sub':

tests/SixtyPical Analysis.md

@@ -440,6 +440,36 @@ You can `add` a word memory location to another word memory location.
     | }
     ? ForbiddenWriteError: a in main
 
+You can `add` a word memory location, or a constant, to a pointer.
+
+    | pointer ptr
+    | word delta
+    | routine main
+    |   inputs ptr, delta
+    |   outputs ptr
+    |   trashes a, c, z, v, n
+    | {
+    |     st off, c
+    |     add ptr, delta
+    |     add ptr, word 1
+    | }
+    = ok
+
+`add`ing a word memory location, or a constant, to a pointer, trashes `a`.
+
+    | pointer ptr
+    | word delta
+    | routine main
+    |   inputs ptr, delta
+    |   outputs ptr
+    |   trashes c, z, v, n
+    | {
+    |     st off, c
+    |     add ptr, delta
+    |     add ptr, word 1
+    | }
+    ? ForbiddenWriteError: a in main
+
 ### sub ###
 
 Can't `sub` from or to a memory location that isn't initialized.

tests/SixtyPical Compilation.md

@@ -437,3 +437,25 @@ Read through a pointer.
     |     copy [ptr] + y, foo
     | }
     = 00c0a000a91085fea9c085ffb1fe8d12c060
+
+Add a word memory location, and a literal word, to a pointer, and then read through it.
+Note that this is *not* range-checked.  (Yet.)
+
+    | buffer[2048] buf
+    | pointer ptr @ 254
+    | byte foo
+    | word delta
+    | 
+    | routine main
+    |   inputs buf
+    |   outputs y, foo, delta
+    |   trashes a, z, n, ptr
+    | {
+    |     copy 619, delta
+    |     ld y, 0
+    |     copy ^buf, ptr
+    |     add ptr, delta
+    |     add ptr, word 1
+    |     copy [ptr] + y, foo
+    | }
+    = 00c0a9028d38c0a96b8d39c0a000a93485fea9c085ffa5fe6d38c085fea5ff6d39c085ffa5fe690185fea5ff690085ffb1fe8d36c060