X-Git-Url: https://git.stderr.nl/gitweb?a=blobdiff_plain;f=interpreters%2Ffrotz%2Fobject.c;fp=interpreters%2Ffrotz%2Fobject.c;h=22ffd080595e09d42c51c2f40161e59b6731d7e2;hb=b1f1dc50b22b30c4d7176e1ff7c0805e80fe0724;hp=0000000000000000000000000000000000000000;hpb=50176172d18ae72d019181725c5629d45d21c548;p=projects%2Fchimara%2Fchimara.git

diff --git a/interpreters/frotz/object.c b/interpreters/frotz/object.c
new file mode 100644
index 0000000..22ffd08
--- /dev/null
+++ b/interpreters/frotz/object.c
@@ -0,0 +1,1003 @@
+/* object.c - Object manipulation opcodes
+ *        Copyright (c) 1995-1997 Stefan Jokisch
+ *
+ * This file is part of Frotz.
+ *
+ * Frotz 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 Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Frotz is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include "frotz.h"
+
+#define MAX_OBJECT 2000
+
+#define O1_PARENT 4
+#define O1_SIBLING 5
+#define O1_CHILD 6
+#define O1_PROPERTY_OFFSET 7
+#define O1_SIZE 9
+
+#define O4_PARENT 6
+#define O4_SIBLING 8
+#define O4_CHILD 10
+#define O4_PROPERTY_OFFSET 12
+#define O4_SIZE 14
+
+/*
+ * object_address
+ *
+ * Calculate the address of an object.
+ *
+ */
+
+static zword object_address (zword obj)
+{
+/*    zchar obj_num[10]; */
+
+    /* Check object number */
+
+    if (obj > ((h_version <= V3) ? 255 : MAX_OBJECT)) {
+        print_string("@Attempt to address illegal object ");
+        print_num(obj);
+        print_string(".  This is normally fatal.");
+        new_line();
+        runtime_error (ERR_ILL_OBJ);
+    }
+
+    /* Return object address */
+
+    if (h_version <= V3)
+        return h_objects + ((obj - 1) * O1_SIZE + 62);
+    else
+        return h_objects + ((obj - 1) * O4_SIZE + 126);
+
+}/* object_address */
+
+/*
+ * object_name
+ *
+ * Return the address of the given object's name.
+ *
+ */
+
+zword object_name (zword object)
+{
+    zword obj_addr;
+    zword name_addr;
+
+    obj_addr = object_address (object);
+
+    /* The object name address is found at the start of the properties */
+
+    if (h_version <= V3)
+        obj_addr += O1_PROPERTY_OFFSET;
+    else
+        obj_addr += O4_PROPERTY_OFFSET;
+
+    LOW_WORD (obj_addr, name_addr)
+
+    return name_addr;
+
+}/* object_name */
+
+/*
+ * first_property
+ *
+ * Calculate the start address of the property list associated with
+ * an object.
+ *
+ */
+
+static zword first_property (zword obj)
+{
+    zword prop_addr;
+    zbyte size;
+
+    /* Fetch address of object name */
+
+    prop_addr = object_name (obj);
+
+    /* Get length of object name */
+
+    LOW_BYTE (prop_addr, size)
+
+    /* Add name length to pointer */
+
+    return prop_addr + 1 + 2 * size;
+
+}/* first_property */
+
+/*
+ * next_property
+ *
+ * Calculate the address of the next property in a property list.
+ *
+ */
+
+static zword next_property (zword prop_addr)
+{
+    zbyte value;
+
+    /* Load the current property id */
+
+    LOW_BYTE (prop_addr, value)
+    prop_addr++;
+
+    /* Calculate the length of this property */
+
+    if (h_version <= V3)
+        value >>= 5;
+    else if (!(value & 0x80))
+        value >>= 6;
+    else {
+
+        LOW_BYTE (prop_addr, value)
+        value &= 0x3f;
+
+        if (value == 0) value = 64;        /* demanded by Spec 1.0 */
+
+    }
+
+    /* Add property length to current property pointer */
+
+    return prop_addr + value + 1;
+
+}/* next_property */
+
+/*
+ * unlink_object
+ *
+ * Unlink an object from its parent and siblings.
+ *
+ */
+
+static void unlink_object (zword object)
+{
+    zword obj_addr;
+    zword parent_addr;
+    zword sibling_addr;
+
+    if (object == 0) {
+        runtime_error (ERR_REMOVE_OBJECT_0);
+        return;
+    }
+
+    obj_addr = object_address (object);
+
+    if (h_version <= V3) {
+
+        zbyte parent;
+        zbyte younger_sibling;
+        zbyte older_sibling;
+        zbyte zero = 0;
+
+        /* Get parent of object, and return if no parent */
+
+        obj_addr += O1_PARENT;
+        LOW_BYTE (obj_addr, parent)
+        if (!parent)
+            return;
+
+        /* Get (older) sibling of object and set both parent and sibling
+           pointers to 0 */
+
+        SET_BYTE (obj_addr, zero)
+        obj_addr += O1_SIBLING - O1_PARENT;
+        LOW_BYTE (obj_addr, older_sibling)
+        SET_BYTE (obj_addr, zero)
+
+        /* Get first child of parent (the youngest sibling of the object) */
+
+        parent_addr = object_address (parent) + O1_CHILD;
+        LOW_BYTE (parent_addr, younger_sibling)
+
+        /* Remove object from the list of siblings */
+
+        if (younger_sibling == object)
+            SET_BYTE (parent_addr, older_sibling)
+        else {
+            do {
+                sibling_addr = object_address (younger_sibling) + O1_SIBLING;
+                LOW_BYTE (sibling_addr, younger_sibling)
+            } while (younger_sibling != object);
+            SET_BYTE (sibling_addr, older_sibling)
+        }
+
+    } else {
+
+        zword parent;
+        zword younger_sibling;
+        zword older_sibling;
+        zword zero = 0;
+
+        /* Get parent of object, and return if no parent */
+
+        obj_addr += O4_PARENT;
+        LOW_WORD (obj_addr, parent)
+        if (!parent)
+            return;
+
+        /* Get (older) sibling of object and set both parent and sibling
+           pointers to 0 */
+
+        SET_WORD (obj_addr, zero)
+        obj_addr += O4_SIBLING - O4_PARENT;
+        LOW_WORD (obj_addr, older_sibling)
+        SET_WORD (obj_addr, zero)
+
+        /* Get first child of parent (the youngest sibling of the object) */
+
+        parent_addr = object_address (parent) + O4_CHILD;
+        LOW_WORD (parent_addr, younger_sibling)
+
+        /* Remove object from the list of siblings */
+
+        if (younger_sibling == object)
+            SET_WORD (parent_addr, older_sibling)
+        else {
+            do {
+                sibling_addr = object_address (younger_sibling) + O4_SIBLING;
+                LOW_WORD (sibling_addr, younger_sibling)
+            } while (younger_sibling != object);
+            SET_WORD (sibling_addr, older_sibling)
+        }
+
+    }
+
+}/* unlink_object */
+
+/*
+ * z_clear_attr, clear an object attribute.
+ *
+ *        zargs[0] = object
+ *        zargs[1] = number of attribute to be cleared
+ *
+ */
+
+void z_clear_attr (void)
+{
+    zword obj_addr;
+    zbyte value;
+
+    if (story_id == SHERLOCK)
+        if (zargs[1] == 48)
+            return;
+
+    if (zargs[1] > ((h_version <= V3) ? 31 : 47))
+        runtime_error (ERR_ILL_ATTR);
+
+    /* If we are monitoring attribute assignment display a short note */
+
+    if (f_setup.attribute_assignment) {
+        stream_mssg_on ();
+        print_string ("@clear_attr ");
+        print_object (zargs[0]);
+        print_string (" ");
+        print_num (zargs[1]);
+        stream_mssg_off ();
+    }
+
+    if (zargs[0] == 0) {
+        runtime_error (ERR_CLEAR_ATTR_0);
+        return;
+    }
+
+    /* Get attribute address */
+
+    obj_addr = object_address (zargs[0]) + zargs[1] / 8;
+
+    /* Clear attribute bit */
+
+    LOW_BYTE (obj_addr, value)
+    value &= ~(0x80 >> (zargs[1] & 7));
+    SET_BYTE (obj_addr, value)
+
+}/* z_clear_attr */
+
+/*
+ * z_jin, branch if the first object is inside the second.
+ *
+ *        zargs[0] = first object
+ *        zargs[1] = second object
+ *
+ */
+
+void z_jin (void)
+{
+    zword obj_addr;
+
+    /* If we are monitoring object locating display a short note */
+
+    if (f_setup.object_locating) {
+        stream_mssg_on ();
+        print_string ("@jin ");
+        print_object (zargs[0]);
+        print_string (" ");
+        print_object (zargs[1]);
+        stream_mssg_off ();
+    }
+
+    if (zargs[0] == 0) {
+        runtime_error (ERR_JIN_0);
+        branch (0 == zargs[1]);
+        return;
+    }
+
+    obj_addr = object_address (zargs[0]);
+
+    if (h_version <= V3) {
+
+        zbyte parent;
+
+        /* Get parent id from object */
+
+        obj_addr += O1_PARENT;
+        LOW_BYTE (obj_addr, parent)
+
+        /* Branch if the parent is obj2 */
+
+        branch (parent == zargs[1]);
+
+    } else {
+
+        zword parent;
+
+        /* Get parent id from object */
+
+        obj_addr += O4_PARENT;
+        LOW_WORD (obj_addr, parent)
+
+        /* Branch if the parent is obj2 */
+
+        branch (parent == zargs[1]);
+
+    }
+
+}/* z_jin */
+
+/*
+ * z_get_child, store the child of an object.
+ *
+ *        zargs[0] = object
+ *
+ */
+
+void z_get_child (void)
+{
+    zword obj_addr;
+
+    /* If we are monitoring object locating display a short note */
+
+    if (f_setup.object_locating) {
+        stream_mssg_on ();
+        print_string ("@get_child ");
+        print_object (zargs[0]);
+        stream_mssg_off ();
+    }
+
+    if (zargs[0] == 0) {
+        runtime_error (ERR_GET_CHILD_0);
+        store (0);
+        branch (FALSE);
+        return;
+    }
+
+    obj_addr = object_address (zargs[0]);
+
+    if (h_version <= V3) {
+
+        zbyte child;
+
+        /* Get child id from object */
+
+        obj_addr += O1_CHILD;
+        LOW_BYTE (obj_addr, child)
+
+        /* Store child id and branch */
+
+        store (child);
+        branch (child);
+
+    } else {
+
+        zword child;
+
+        /* Get child id from object */
+
+        obj_addr += O4_CHILD;
+        LOW_WORD (obj_addr, child)
+
+        /* Store child id and branch */
+
+        store (child);
+        branch (child);
+
+    }
+
+}/* z_get_child */
+
+/*
+ * z_get_next_prop, store the number of the first or next property.
+ *
+ *        zargs[0] = object
+ *        zargs[1] = address of current property (0 gets the first property)
+ *
+ */
+
+void z_get_next_prop (void)
+{
+    zword prop_addr;
+    zbyte value;
+    zbyte mask;
+
+    if (zargs[0] == 0) {
+        runtime_error (ERR_GET_NEXT_PROP_0);
+        store (0);
+        return;
+    }
+
+    /* Property id is in bottom five (six) bits */
+
+    mask = (h_version <= V3) ? 0x1f : 0x3f;
+
+    /* Load address of first property */
+
+    prop_addr = first_property (zargs[0]);
+
+    if (zargs[1] != 0) {
+
+        /* Scan down the property list */
+
+        do {
+            LOW_BYTE (prop_addr, value)
+            prop_addr = next_property (prop_addr);
+        } while ((value & mask) > zargs[1]);
+
+        /* Exit if the property does not exist */
+
+        if ((value & mask) != zargs[1])
+            runtime_error (ERR_NO_PROP);
+
+    }
+
+    /* Return the property id */
+
+    LOW_BYTE (prop_addr, value)
+    store ((zword) (value & mask));
+
+}/* z_get_next_prop */
+
+/*
+ * z_get_parent, store the parent of an object.
+ *
+ *        zargs[0] = object
+ *
+ */
+
+void z_get_parent (void)
+{
+    zword obj_addr;
+
+    /* If we are monitoring object locating display a short note */
+
+    if (f_setup.object_locating) {
+        stream_mssg_on ();
+        print_string ("@get_parent ");
+        print_object (zargs[0]);
+        stream_mssg_off ();
+    }
+
+    if (zargs[0] == 0) {
+        runtime_error (ERR_GET_PARENT_0);
+        store (0);
+        return;
+    }
+
+    obj_addr = object_address (zargs[0]);
+
+    if (h_version <= V3) {
+
+        zbyte parent;
+
+        /* Get parent id from object */
+
+        obj_addr += O1_PARENT;
+        LOW_BYTE (obj_addr, parent)
+
+        /* Store parent */
+
+        store (parent);
+
+    } else {
+
+        zword parent;
+
+        /* Get parent id from object */
+
+        obj_addr += O4_PARENT;
+        LOW_WORD (obj_addr, parent)
+
+        /* Store parent */
+
+        store (parent);
+
+    }
+
+}/* z_get_parent */
+
+/*
+ * z_get_prop, store the value of an object property.
+ *
+ *        zargs[0] = object
+ *        zargs[1] = number of property to be examined
+ *
+ */
+
+void z_get_prop (void)
+{
+    zword prop_addr;
+    zword wprop_val;
+    zbyte bprop_val;
+    zbyte value;
+    zbyte mask;
+
+    if (zargs[0] == 0) {
+        runtime_error (ERR_GET_PROP_0);
+        store (0);
+        return;
+    }
+
+    /* Property id is in bottom five (six) bits */
+
+    mask = (h_version <= V3) ? 0x1f : 0x3f;
+
+    /* Load address of first property */
+
+    prop_addr = first_property (zargs[0]);
+
+    /* Scan down the property list */
+
+    for (;;) {
+        LOW_BYTE (prop_addr, value)
+        if ((value & mask) <= zargs[1])
+            break;
+        prop_addr = next_property (prop_addr);
+    }
+
+    if ((value & mask) == zargs[1]) {        /* property found */
+
+        /* Load property (byte or word sized) */
+
+        prop_addr++;
+
+        if ((h_version <= V3 && !(value & 0xe0)) || (h_version >= V4 && !(value & 0xc0))) {
+
+            LOW_BYTE (prop_addr, bprop_val)
+            wprop_val = bprop_val;
+
+        } else LOW_WORD (prop_addr, wprop_val)
+
+    } else {        /* property not found */
+
+        /* Load default value */
+
+        prop_addr = h_objects + 2 * (zargs[1] - 1);
+        LOW_WORD (prop_addr, wprop_val)
+
+    }
+
+    /* Store the property value */
+
+    store (wprop_val);
+
+}/* z_get_prop */
+
+/*
+ * z_get_prop_addr, store the address of an object property.
+ *
+ *        zargs[0] = object
+ *        zargs[1] = number of property to be examined
+ *
+ */
+
+void z_get_prop_addr (void)
+{
+    zword prop_addr;
+    zbyte value;
+    zbyte mask;
+
+    if (zargs[0] == 0) {
+        runtime_error (ERR_GET_PROP_ADDR_0);
+        store (0);
+        return;
+    }
+
+    if (story_id == BEYOND_ZORK)
+        if (zargs[0] > MAX_OBJECT)
+            { store (0); return; }
+
+    /* Property id is in bottom five (six) bits */
+
+    mask = (h_version <= V3) ? 0x1f : 0x3f;
+
+    /* Load address of first property */
+
+    prop_addr = first_property (zargs[0]);
+
+    /* Scan down the property list */
+
+    for (;;) {
+        LOW_BYTE (prop_addr, value)
+        if ((value & mask) <= zargs[1])
+            break;
+        prop_addr = next_property (prop_addr);
+    }
+
+    /* Calculate the property address or return zero */
+
+    if ((value & mask) == zargs[1]) {
+
+        if (h_version >= V4 && (value & 0x80))
+            prop_addr++;
+        store ((zword) (prop_addr + 1));
+
+    } else store (0);
+
+}/* z_get_prop_addr */
+
+/*
+ * z_get_prop_len, store the length of an object property.
+ *
+ *         zargs[0] = address of property to be examined
+ *
+ */
+
+void z_get_prop_len (void)
+{
+    zword addr;
+    zbyte value;
+
+    /* Back up the property pointer to the property id */
+
+    addr = zargs[0] - 1;
+    LOW_BYTE (addr, value)
+
+    /* Calculate length of property */
+
+    if (h_version <= V3)
+        value = (value >> 5) + 1;
+    else if (!(value & 0x80))
+        value = (value >> 6) + 1;
+    else {
+
+        value &= 0x3f;
+
+        if (value == 0) value = 64;        /* demanded by Spec 1.0 */
+
+    }
+
+    /* Store length of property */
+
+    store (value);
+
+}/* z_get_prop_len */
+
+/*
+ * z_get_sibling, store the sibling of an object.
+ *
+ *        zargs[0] = object
+ *
+ */
+
+void z_get_sibling (void)
+{
+    zword obj_addr;
+
+    if (zargs[0] == 0) {
+        runtime_error (ERR_GET_SIBLING_0);
+        store (0);
+        branch (FALSE);
+        return;
+    }
+
+    obj_addr = object_address (zargs[0]);
+
+    if (h_version <= V3) {
+
+        zbyte sibling;
+
+        /* Get sibling id from object */
+
+        obj_addr += O1_SIBLING;
+        LOW_BYTE (obj_addr, sibling)
+
+        /* Store sibling and branch */
+
+        store (sibling);
+        branch (sibling);
+
+    } else {
+
+        zword sibling;
+
+        /* Get sibling id from object */
+
+        obj_addr += O4_SIBLING;
+        LOW_WORD (obj_addr, sibling)
+
+        /* Store sibling and branch */
+
+        store (sibling);
+        branch (sibling);
+
+    }
+
+}/* z_get_sibling */
+
+/*
+ * z_insert_obj, make an object the first child of another object.
+ *
+ *        zargs[0] = object to be moved
+ *        zargs[1] = destination object
+ *
+ */
+
+void z_insert_obj (void)
+{
+    zword obj1 = zargs[0];
+    zword obj2 = zargs[1];
+    zword obj1_addr;
+    zword obj2_addr;
+
+    /* If we are monitoring object movements display a short note */
+
+    if (f_setup.object_movement) {
+        stream_mssg_on ();
+        print_string ("@move_obj ");
+        print_object (obj1);
+        print_string (" ");
+        print_object (obj2);
+        stream_mssg_off ();
+    }
+
+    if (obj1 == 0) {
+        runtime_error (ERR_MOVE_OBJECT_0);
+        return;
+    }
+
+    if (obj2 == 0) {
+        runtime_error (ERR_MOVE_OBJECT_TO_0);
+        return;
+    }
+
+    /* Get addresses of both objects */
+
+    obj1_addr = object_address (obj1);
+    obj2_addr = object_address (obj2);
+
+    /* Remove object 1 from current parent */
+
+    unlink_object (obj1);
+
+    /* Make object 1 first child of object 2 */
+
+    if (h_version <= V3) {
+
+        zbyte child;
+
+        obj1_addr += O1_PARENT;
+        SET_BYTE (obj1_addr, obj2)
+        obj2_addr += O1_CHILD;
+        LOW_BYTE (obj2_addr, child)
+        SET_BYTE (obj2_addr, obj1)
+        obj1_addr += O1_SIBLING - O1_PARENT;
+        SET_BYTE (obj1_addr, child)
+
+    } else {
+
+        zword child;
+
+        obj1_addr += O4_PARENT;
+        SET_WORD (obj1_addr, obj2)
+        obj2_addr += O4_CHILD;
+        LOW_WORD (obj2_addr, child)
+        SET_WORD (obj2_addr, obj1)
+        obj1_addr += O4_SIBLING - O4_PARENT;
+        SET_WORD (obj1_addr, child)
+
+    }
+
+}/* z_insert_obj */
+
+/*
+ * z_put_prop, set the value of an object property.
+ *
+ *        zargs[0] = object
+ *        zargs[1] = number of property to set
+ *        zargs[2] = value to set property to
+ *
+ */
+
+void z_put_prop (void)
+{
+    zword prop_addr;
+    zword value;
+    zbyte mask;
+
+    if (zargs[0] == 0) {
+        runtime_error (ERR_PUT_PROP_0);
+        return;
+    }
+
+    /* Property id is in bottom five or six bits */
+
+    mask = (h_version <= V3) ? 0x1f : 0x3f;
+
+    /* Load address of first property */
+
+    prop_addr = first_property (zargs[0]);
+
+    /* Scan down the property list */
+
+    for (;;) {
+        LOW_BYTE (prop_addr, value)
+        if ((value & mask) <= zargs[1])
+            break;
+        prop_addr = next_property (prop_addr);
+    }
+
+    /* Exit if the property does not exist */
+
+    if ((value & mask) != zargs[1])
+        runtime_error (ERR_NO_PROP);
+
+    /* Store the new property value (byte or word sized) */
+
+    prop_addr++;
+
+    if ((h_version <= V3 && !(value & 0xe0)) || (h_version >= V4 && !(value & 0xc0))) {
+        zbyte v = zargs[2];
+        SET_BYTE (prop_addr, v)
+    } else {
+        zword v = zargs[2];
+        SET_WORD (prop_addr, v)
+    }
+
+}/* z_put_prop */
+
+/*
+ * z_remove_obj, unlink an object from its parent and siblings.
+ *
+ *        zargs[0] = object
+ *
+ */
+
+void z_remove_obj (void)
+{
+
+    /* If we are monitoring object movements display a short note */
+
+    if (f_setup.object_movement) {
+        stream_mssg_on ();
+        print_string ("@remove_obj ");
+        print_object (zargs[0]);
+        stream_mssg_off ();
+    }
+
+    /* Call unlink_object to do the job */
+
+    unlink_object (zargs[0]);
+
+}/* z_remove_obj */
+
+/*
+ * z_set_attr, set an object attribute.
+ *
+ *        zargs[0] = object
+ *        zargs[1] = number of attribute to set
+ *
+ */
+
+void z_set_attr (void)
+{
+    zword obj_addr;
+    zbyte value;
+
+    if (story_id == SHERLOCK)
+        if (zargs[1] == 48)
+            return;
+
+    if (zargs[1] > ((h_version <= V3) ? 31 : 47))
+        runtime_error (ERR_ILL_ATTR);
+
+    /* If we are monitoring attribute assignment display a short note */
+
+    if (f_setup.attribute_assignment) {
+        stream_mssg_on ();
+        print_string ("@set_attr ");
+        print_object (zargs[0]);
+        print_string (" ");
+        print_num (zargs[1]);
+        stream_mssg_off ();
+    }
+
+    if (zargs[0] == 0) {
+        runtime_error (ERR_SET_ATTR_0);
+        return;
+    }
+
+    /* Get attribute address */
+
+    obj_addr = object_address (zargs[0]) + zargs[1] / 8;
+
+    /* Load attribute byte */
+
+    LOW_BYTE (obj_addr, value)
+
+    /* Set attribute bit */
+
+    value |= 0x80 >> (zargs[1] & 7);
+
+    /* Store attribute byte */
+
+    SET_BYTE (obj_addr, value)
+
+}/* z_set_attr */
+
+/*
+ * z_test_attr, branch if an object attribute is set.
+ *
+ *        zargs[0] = object
+ *        zargs[1] = number of attribute to test
+ *
+ */
+
+void z_test_attr (void)
+{
+    zword obj_addr;
+    zbyte value;
+
+    if (zargs[1] > ((h_version <= V3) ? 31 : 47))
+        runtime_error (ERR_ILL_ATTR);
+
+    /* If we are monitoring attribute testing display a short note */
+
+    if (f_setup.attribute_testing) {
+        stream_mssg_on ();
+        print_string ("@test_attr ");
+        print_object (zargs[0]);
+        print_string (" ");
+        print_num (zargs[1]);
+        stream_mssg_off ();
+    }
+
+    if (zargs[0] == 0) {
+        runtime_error (ERR_TEST_ATTR_0);
+        branch (FALSE);
+        return;
+    }
+
+    /* Get attribute address */
+
+    obj_addr = object_address (zargs[0]) + zargs[1] / 8;
+
+    /* Load attribute byte */
+
+    LOW_BYTE (obj_addr, value)
+
+    /* Test attribute */
+
+    branch (value & (0x80 >> (zargs[1] & 7)));
+
+}/* z_test_attr */