Initial value for locations: changed syntax, executes, compiles.

HISTORY.markdown

@@ -1,6 +1,11 @@
 History of SixtyPical
 =====================
 
+0.7-PRE
+-------
+
+*   User-defined `byte` locations can be given an initial value.
+
 0.6
 ---
 

README.markdown

@@ -44,8 +44,6 @@ TODO
 
 For 0.7:
 
-*   initialized `byte` memory locations
-*   initialized `byte table` memory locations
 *   `word` type.
 *   `word table` type.
 
@@ -60,6 +58,7 @@ For 0.9
 
 At some point...
 
+*   initialized `byte table` memory locations
 *   always analyze before executing or compiling, unless told not to
 *   `trash` instruction.
 *   `interrupt` routines.

doc/SixtyPical.md

@@ -86,8 +86,7 @@ An address in memory may be given explicitly on a user-defined memory location.
 Or, a user-defined memory location may be given an initial value.  But in this
 case, an explicit address in memory cannot be given.
 
-    byte pos = 0
-    byte table scores = [1, 3, 8, 17, 26, 100]
+    byte pos : 0
 
 A user-defined vector memory location is decorated with READS and WRITES lists
 like a routine (see below), and it may only hold addresses of routines which

src/sixtypical/compiler.py

@@ -57,8 +57,16 @@ class Compiler(object):
             self.emitter.resolve_label(label)
             self.emitter.emit(JMP(Indirect(self.labels[location.name])))
 
+        # initialized data
         for defn in program.defns:
-            if defn.addr is None:
+            if defn.initial is not None:
+                label = self.labels[defn.name]
+                self.emitter.resolve_label(label)
+                self.emitter.emit(Byte(defn.initial))
+
+        # uninitialized, "BSS" data
+        for defn in program.defns:
+            if defn.initial is None and defn.addr is None:
                 label = self.labels[defn.name]
                 self.emitter.resolve_bss_label(label)
 

src/sixtypical/evaluator.py

@@ -37,10 +37,16 @@ class Evaluator(object):
         for ref in (REG_A, REG_X, REG_Y, FLAG_Z, FLAG_N, FLAG_V, FLAG_C):
             context.set(ref, 0)
         main = None
+
+        for defn in program.defns:
+            if defn.initial is not None:
+                context.set(defn.location, defn.initial)
+
         for routine in program.routines:
             context.set(routine.location, routine)
             if routine.name == 'main':
                 main = routine
+
         self.eval_routine(main, context)
         return context
 

src/sixtypical/parser.py

@@ -36,7 +36,7 @@ class Scanner(object):
             self.token = None
             self.type = 'EOF'
             return
-        if self.scan_pattern(r'\,|\@|\+|\{|\}', 'operator'):
+        if self.scan_pattern(r'\,|\@|\+|\:|\{|\}', 'operator'):
             return
         if self.scan_pattern(r'\d+', 'integer literal'):
             return
@@ -140,13 +140,24 @@ class Parser(object):
         elif inputs or outputs or trashes:
             raise SyntaxError("Cannot apply constraints to non-vector type")
 
+        initial = None
+        if self.scanner.consume(':'):
+            self.scanner.check_type('integer literal')
+            initial = int(self.scanner.token)
+            self.scanner.scan()
+
         addr = None
         if self.scanner.consume('@'):
             self.scanner.check_type('integer literal')
             addr = int(self.scanner.token)
             self.scanner.scan()
+
+        if initial is not None and addr is not None:
+            raise SyntaxError("Definition cannot have both initial value and explicit address")
+
         location = LocationRef(type, name)
-        return Defn(name=name, addr=addr, location=location)
+
+        return Defn(name=name, addr=addr, initial=initial, location=location)
 
     def constraints(self):
         inputs = set()

tests/SixtyPical Compilation.md

@@ -77,6 +77,8 @@ Access a defined memory location.
     | }
     = 00c0a0008c09c0ad09c060
 
+Memory location with explicit address.
+
     | byte screen @ 1024
     | 
     | routine main
@@ -87,6 +89,18 @@ Access a defined memory location.
     | }
     = 00c0a9648d000460
 
+Memory location with initial value.
+
+    | byte lives : 3
+    | 
+    | routine main
+    |   inputs lives
+    |   trashes a, z, n
+    | {
+    |   ld a, lives
+    | }
+    = 00c0ad04c06003
+
 Some instructions.
 
     | byte foo

tests/SixtyPical Execution.md

@@ -45,6 +45,22 @@ Program accesses a memory location.
     = y: 0
     = z: 0
 
+Program accesses a memory location with initial value.
+
+    | byte lives : 3
+    | 
+    | routine main {
+    |     ld a, lives
+    | }
+    = a: 3
+    = c: 0
+    = lives: 3
+    = n: 0
+    = v: 0
+    = x: 0
+    = y: 0
+    = z: 0
+
 Add honours carry.
 
     | routine main {

tests/SixtyPical Syntax.md

@@ -123,7 +123,7 @@ Repeat with not
     | }
     = ok
 
-Extern memory locations.
+Explicit memory address.
 
     | byte screen @ 1024
     | 
@@ -135,7 +135,7 @@ Extern memory locations.
 
 Initialized memory locations.
 
-    | byte lives = 3
+    | byte lives : 3
     | 
     | routine main {
     |   ld a, lives
@@ -143,6 +143,16 @@ Initialized memory locations.
     | }
     = ok
 
+Cannot have both initial value and explicit address.
+
+    | byte screen : 3 @ 1024
+    | 
+    | routine main {
+    |   ld a, lives
+    |   st a, lives
+    | }
+    ? SyntaxError
+
 Can't access an undeclared memory location.
 
     | routine main {