Initial work on adding 16-bit constants to a 16-bit location.

src/sixtypical/analyzer.py

@@ -2,7 +2,7 @@
 
 from sixtypical.ast import Program, Routine, Block, Instr
 from sixtypical.model import (
-    TYPE_BYTE, TYPE_BYTE_TABLE, BufferType, PointerType, VectorType, ExecutableType,
+    TYPE_BYTE, TYPE_WORD, TYPE_BYTE_TABLE, BufferType, PointerType, VectorType, ExecutableType,
     ConstantRef, LocationRef, IndirectRef, AddressRef,
     REG_A, REG_Y, FLAG_Z, FLAG_N, FLAG_V, FLAG_C
 )
@@ -233,7 +233,17 @@ class Analyzer(object):
                 )
             context.assert_meaningful(src)
             context.set_written(dest)
-        elif opcode in ('add', 'sub'):
+        elif opcode == 'add':
+            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_unmeaningful(REG_A)
+        elif opcode == 'sub':
             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)

tests/SixtyPical Analysis.md

@@ -373,6 +373,45 @@ Can't `add` to a memory location that isn't writeable.
     | }
     ? ForbiddenWriteError: a in main
 
+You can `add` a word constant to a word memory location.
+
+    | word score
+    | routine main
+    |   inputs a, score
+    |   outputs score
+    |   trashes a, c, z, v, n
+    | {
+    |     st off, c
+    |     add score, 1999
+    | }
+    = ok
+
+`add`ing a word constant to a word memory location trashes `a`.
+
+    | word score
+    | routine main
+    |   inputs a, score
+    |   outputs score, a
+    |   trashes c, z, v, n
+    | {
+    |     st off, c
+    |     add score, 1999
+    | }
+    ? UnmeaningfulOutputError: a in main
+
+Not sure why this doesn't also raise an error?  `a` is trashed...
+
+    | word score
+    | routine main
+    |   inputs score
+    |   outputs score
+    |   trashes c, z, v, n
+    | {
+    |     st off, c
+    |     add score, 1999
+    | }
+    ? UnmeaningfulOutputError: a in main
+
 ### sub ###
 
 Can't `sub` from or to a memory location that isn't initialized.