# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1636214761 -3600
# Node ID c7bd72a6309b4e5a4f74f8b0f98110dc0aeef4e0
# Parent  150186eee8e780f64b5a3eb1f4c382b9752b57e7
Introduced a mutable value tag in place of type-specific tags.

diff -r 150186eee8e7 -r c7bd72a6309b templates/native/common.c
--- a/templates/native/common.c	Sat Nov 06 01:05:42 2021 +0100
+++ b/templates/native/common.c	Sat Nov 06 17:06:01 2021 +0100
@@ -31,7 +31,7 @@
     /* Create a new int and set the trailing data. */
     __attr attr = __NEWINSTANCEIM(__builtins___int_int);
     __set_trailing_data(attr, __builtins___int_int, n);
-    return attr;
+    return __TO_MUTABLE(attr);
 }
 
 __attr __new_str(char *s, __int size)
@@ -57,7 +57,7 @@
     /* Create a new float and set the trailing data. */
     __attr attr = __NEWINSTANCEIM(__builtins___float_float);
     __set_trailing_data(attr, __builtins___float_float, n);
-    return attr;
+    return __TO_MUTABLE(attr);
 }
 
 __fragment *__fragment_append(__fragment *data, __attr value)
diff -r 150186eee8e7 -r c7bd72a6309b templates/ops.c
--- a/templates/ops.c	Sat Nov 06 01:05:42 2021 +0100
+++ b/templates/ops.c	Sat Nov 06 17:06:01 2021 +0100
@@ -1,6 +1,6 @@
 /* Common operations.
 
-Copyright (C) 2015, 2016, 2017, 2018, 2021 Paul Boddie <paul@boddie.org.uk>
+Copyright (C) 2015-2018, 2021 Paul Boddie <paul@boddie.org.uk>
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -27,7 +27,7 @@
 
 __ref __VALUE(__attr attr)
 {
-    return attr.value;
+    return (__ref) (attr.rawvalue & (~__TAG_MASK));
 }
 
 /* Basic structure tests. */
diff -r 150186eee8e7 -r c7bd72a6309b templates/ops.h
--- a/templates/ops.h	Sat Nov 06 01:05:42 2021 +0100
+++ b/templates/ops.h	Sat Nov 06 17:06:01 2021 +0100
@@ -1,6 +1,6 @@
 /* Common operations.
 
-Copyright (C) 2015, 2016, 2017, 2018 Paul Boddie <paul@boddie.org.uk>
+Copyright (C) 2015-2018, 2021 Paul Boddie <paul@boddie.org.uk>
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -136,7 +136,7 @@
 
 __ref __ISFUNC(__ref obj);
 
-#define __ISNULL(__ATTR) (!__ATTR.value)
+#define __ISNULL(__ATTR) (!(__ATTR.rawvalue & (~__TAG_MASK)))
 
 /* Attribute codes and positions for type objects. */
 
diff -r 150186eee8e7 -r c7bd72a6309b templates/progops.c
--- a/templates/progops.c	Sat Nov 06 01:05:42 2021 +0100
+++ b/templates/progops.c	Sat Nov 06 17:06:01 2021 +0100
@@ -332,7 +332,7 @@
     /* Test against True and False explicitly. If necessary, invoke the bool
        function with the object and test against True. */
 
-    value = attr.value;
+    value = __VALUE(attr);
 
     return value == (__ref) &__predefined___builtins___boolean_True ? 1 :
            value == (__ref) &__predefined___builtins___boolean_False ? 0 :
diff -r 150186eee8e7 -r c7bd72a6309b templates/progops.h
--- a/templates/progops.h	Sat Nov 06 01:05:42 2021 +0100
+++ b/templates/progops.h	Sat Nov 06 17:06:01 2021 +0100
@@ -90,8 +90,8 @@
 
 /* Operations for accessing trailing data. */
 
-#define __get_trailing_data(ATTR, TYPE) (((__OBJTYPE(TYPE) *) ((ATTR).value))->trailing)
-#define __set_trailing_data(ATTR, TYPE, VALUE) ((__OBJTYPE(TYPE) *) ((ATTR).value))->trailing = VALUE;
+#define __get_trailing_data(ATTR, TYPE) (((__OBJTYPE(TYPE) *) (__VALUE(ATTR)))->trailing)
+#define __set_trailing_data(ATTR, TYPE, VALUE) ((__OBJTYPE(TYPE) *) (__VALUE(ATTR)))->trailing = VALUE;
 
 /* Specialised trailing data functions. */
 
diff -r 150186eee8e7 -r c7bd72a6309b templates/types.h
--- a/templates/types.h	Sat Nov 06 01:05:42 2021 +0100
+++ b/templates/types.h	Sat Nov 06 17:06:01 2021 +0100
@@ -130,15 +130,12 @@
 
 /* Attribute interpretation. */
 
-#define __NUM_TAG_BITS      2
-#define __TAG_INT           0b01
-#define __TAG_FLOAT         0b10
-#define __TAG_MASK          0b11
+#define __NUM_TAG_BITS      1
+#define __TAG_MUTABLE       0b1
+#define __TAG_MASK          0b1
 
-#if 0
-#define __INTEGER(ATTR)     (((ATTR).rawvalue & __TAG_MASK) == __TAG_INT)
-#define __FLOAT(ATTR)       (((ATTR).rawvalue & __TAG_MASK) == __TAG_FLOAT)
-#endif
+#define __MUTABLE(ATTR)     (((ATTR).rawvalue & __TAG_MASK) == __TAG_MUTABLE)
+#define __TO_MUTABLE(ATTR)  ((__attr) (((ATTR).rawvalue & (~__TAG_MASK)) | __TAG_MUTABLE))
 
 /* Attribute value setting. */