New plugin: frotz, a Z-machine interpreter, for playing interactive fiction.

The interpreter more or less passes all the tests in the z-machine test suite.
It should build for every target except Archos (for which it is disabled).


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@24267 a1c6a512-1295-4272-9138-f99709370657

apps/plugins/frotz/table.c

@@ -0,0 +1,193 @@
+/* table.c - Table handling 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"
+
+/*
+ * z_copy_table, copy a table or fill it with zeroes.
+ *
+ *	zargs[0] = address of table
+ * 	zargs[1] = destination address or 0 for fill
+ *	zargs[2] = size of table
+ *
+ * Note: Copying is safe even when source and destination overlap; but
+ *       if zargs[1] is negative the table _must_ be copied forwards.
+ *
+ */
+
+void z_copy_table (void)
+{
+    zword addr;
+    zword size = zargs[2];
+    zbyte value;
+    int i;
+
+    if (zargs[1] == 0)      				/* zero table */
+
+	for (i = 0; i < size; i++)
+	    storeb ((zword) (zargs[0] + i), 0);
+
+    else if ((short) size < 0 || zargs[0] > zargs[1])	/* copy forwards */
+
+	for (i = 0; i < (((short) size < 0) ? - (short) size : size); i++) {
+	    addr = zargs[0] + i;
+	    LOW_BYTE (addr, value)
+	    storeb ((zword) (zargs[1] + i), value);
+	}
+
+    else						/* copy backwards */
+
+	for (i = size - 1; i >= 0; i--) {
+	    addr = zargs[0] + i;
+	    LOW_BYTE (addr, value)
+	    storeb ((zword) (zargs[1] + i), value);
+	}
+
+}/* z_copy_table */
+
+/*
+ * z_loadb, store a value from a table of bytes.
+ *
+ *	zargs[0] = address of table
+ *	zargs[1] = index of table entry to store
+ *
+ */
+
+void z_loadb (void)
+{
+    zword addr = zargs[0] + zargs[1];
+    zbyte value;
+
+    LOW_BYTE (addr, value)
+
+    store (value);
+
+}/* z_loadb */
+
+/*
+ * z_loadw, store a value from a table of words.
+ *
+ *	zargs[0] = address of table
+ *	zargs[1] = index of table entry to store
+ *
+ */
+
+void z_loadw (void)
+{
+    zword addr = zargs[0] + 2 * zargs[1];
+    zword value;
+
+    LOW_WORD (addr, value)
+
+    store (value);
+
+}/* z_loadw */
+
+/*
+ * z_scan_table, find and store the address of a target within a table.
+ *
+ *	zargs[0] = target value to be searched for
+ *	zargs[1] = address of table
+ *	zargs[2] = number of table entries to check value against
+ *	zargs[3] = type of table (optional, defaults to 0x82)
+ *
+ * Note: The table is a word array if bit 7 of zargs[3] is set; otherwise
+ *       it's a byte array. The lower bits hold the address step.
+ *
+ */
+
+void z_scan_table (void)
+{
+    zword addr = zargs[1];
+    int i;
+
+    /* Supply default arguments */
+
+    if (zargc < 4)
+	zargs[3] = 0x82;
+
+    /* Scan byte or word array */
+
+    for (i = 0; i < zargs[2]; i++) {
+
+	if (zargs[3] & 0x80) {	/* scan word array */
+
+	    zword wvalue;
+
+	    LOW_WORD (addr, wvalue)
+
+	    if (wvalue == zargs[0])
+		goto finished;
+
+	} else {		/* scan byte array */
+
+	    zbyte bvalue;
+
+	    LOW_BYTE (addr, bvalue)
+
+	    if (bvalue == zargs[0])
+		goto finished;
+
+	}
+
+	addr += zargs[3] & 0x7f;
+
+    }
+
+    addr = 0;
+
+finished:
+
+    store (addr);
+    branch (addr);
+
+}/* z_scan_table */
+
+/*
+ * z_storeb, write a byte into a table of bytes.
+ *
+ *	zargs[0] = address of table
+ *	zargs[1] = index of table entry
+ *	zargs[2] = value to be written
+ *
+ */
+
+void z_storeb (void)
+{
+
+    storeb ((zword) (zargs[0] + zargs[1]), zargs[2]);
+
+}/* z_storeb */
+
+/*
+ * z_storew, write a word into a table of words.
+ *
+ *	zargs[0] = address of table
+ *	zargs[1] = index of table entry
+ *	zargs[2] = value to be written
+ *
+ */
+
+void z_storew (void)
+{
+
+    storew ((zword) (zargs[0] + 2 * zargs[1]), zargs[2]);
+
+}/* z_storew */