Spec and syntax for vectors and copy instruction.

README.markdown

@@ -51,3 +51,4 @@ At some point...
 *   6502-mnemonic aliases (`sec`, `clc`)
 *   other handy aliases (`eq` for `z`, etc.)
 *   add absolute addressing in shl/shr, absolute-indexed for add, sub, etc.
+*   check and disallow recursion.

doc/SixtyPical.md

@@ -1,7 +1,7 @@
 SixtyPical
 ==========
 
-This document describes the SixtyPical programming language version 0.5,
+This document describes the SixtyPical programming language version 0.6-PRE,
 both its execution aspect and its static analysis aspect (even though
 these are, technically speaking, separate concepts.)
 
@@ -14,11 +14,13 @@ the language.
 Types
 -----
 
-There are three TYPES in SixtyPical:
+There are five TYPES in SixtyPical:
 
 *   bit (2 possible values)
 *   byte (256 possible values)
 *   byte table (256 entries, each holding a byte)
+*   routine (code stored somewhere in memory, read-only)
+*   vector (address of a routine)
 
 Memory locations
 ----------------
@@ -72,13 +74,14 @@ and two-hundred and fifty-six byte constants,
 ### User-defined ###
 
 There may be any number of user-defined memory locations.  They are defined
-by giving the type, which must be `byte`, and the name.
+by giving the type, which must be `byte`, `byte table`, or `vector`, and the
+name.
 
     byte pos
 
 A location in memory may be given explicitly on a user-defined memory location.
 
-    byte screen @ 1024
+    byte table screen @ 1024
 
 Routines
 --------
@@ -326,6 +329,23 @@ To simulate a "while" loop, use an `if` internal to the block, like
 
 "until" is optional, but if omitted, must be replaced with "forever".
 
+### copy ###
+
+    copy <src-memory-location>, <dest-memory-location>
+
+Reads from src and writes to dest.  Differs from `st` in that is able to
+copy more general types of data (for example, vectors,) and it sets the
+`z` and `n` flags and trashes the `a` register.
+
+*   It is illegal if dest is read-only.
+*   It is illegal if dest does not occur in the WRITES lists of the current
+    routine.
+*   It is illegal if src is not of same type as dest.
+*   It is illegal if src is uninitialized.
+
+After execution, dest is considered initialized, as are `z` and `n`, while
+`a` is considered uninitialized.
+
 Grammar
 -------
 
@@ -356,4 +376,5 @@ Grammar
               | "call" RoutineIdent
               | "if" ["not"] LocExpr Block ["else" Block]
               | "repeat" Block ("until" ["not"] LocExpr | "forever")
+              | "copy" LocExpr "," LocExpr ["+" LocExpr]
               .

src/sixtypical/model.py

@@ -17,6 +17,8 @@ class Type(object):
 TYPE_BIT = Type('bit')
 TYPE_BYTE = Type('byte')
 TYPE_BYTE_TABLE = Type('byte table')
+TYPE_ROUTINE = Type('routine')
+TYPE_VECTOR = Type('vector')      # the mem loc contains an address of a routine
 
 
 class Ref(object):

src/sixtypical/parser.py

@@ -4,7 +4,7 @@ import re
 
 from sixtypical.ast import Program, Defn, Routine, Block, Instr
 from sixtypical.model import (
-    TYPE_BIT, TYPE_BYTE, TYPE_BYTE_TABLE,
+    TYPE_BIT, TYPE_BYTE, TYPE_BYTE_TABLE, TYPE_ROUTINE, TYPE_VECTOR,
     LocationRef, ConstantRef
 )
 
@@ -103,7 +103,7 @@ class Parser(object):
     def program(self):
         defns = []
         routines = []
-        while self.scanner.on('byte'):
+        while self.scanner.on('byte') or self.scanner.on('vector'):
             defn = self.defn()
             name = defn.name
             if name in self.symbols:
@@ -115,16 +115,20 @@ class Parser(object):
             name = routine.name
             if name in self.symbols:
                 raise SyntaxError(name)
-            self.symbols[name] = SymEntry(routine, None)
+            self.symbols[name] = SymEntry(routine, LocationRef(TYPE_ROUTINE, name))
             routines.append(routine)
         self.scanner.check_type('EOF')
         return Program(defns=defns, routines=routines)
 
     def defn(self):
         type = TYPE_BYTE
-        self.scanner.expect('byte')
-        if self.scanner.consume('table'):
-            type = TYPE_BYTE_TABLE
+        if self.scanner.consume('byte'):
+            type = TYPE_BYTE
+            if self.scanner.consume('table'):
+                type = TYPE_BYTE_TABLE
+        else:
+            self.scanner.expect('vector')
+            type = TYPE_VECTOR
         self.scanner.check_type('identifier')
         name = self.scanner.token
         self.scanner.scan()
@@ -246,5 +250,12 @@ class Parser(object):
             self.scanner.scan()
             # TODO: check that is has been defined
             return Instr(opcode=opcode, name=name, dest=None, src=None)
+        elif self.scanner.token in ("copy",):
+            opcode = self.scanner.token
+            self.scanner.scan()
+            src = self.locexpr()
+            self.scanner.expect(',')
+            dest = self.locexpr()
+            return Instr(opcode=opcode, dest=dest, src=src)
         else:
             raise ValueError('bad opcode "%s"' % self.scanner.token)

tests/SixtyPical Syntax.md

@@ -196,3 +196,15 @@ Declaring a byte table memory location.
     |     st a, tab + y
     | }
     = ok
+
+Declaring a vector.
+
+    | vector cinv
+    | 
+    | routine foo {
+    |     ld a, 0
+    | }
+    | routine main {
+    |     copy foo, cinv
+    | }
+    = ok