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RCS file: /home/cvs/OpenXM/doc/issac2000/openxm-stackmachines.tex,v
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--- OpenXM/doc/issac2000/openxm-stackmachines.tex	1999/12/23 10:25:09	1.1
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-% $OpenXM$
+% $OpenXM: OpenXM/doc/issac2000/openxm-stackmachines.tex,v 1.3 2000/01/03 04:27:52 takayama Exp $
+
+\section{OpenXM Stack machines}   (Tamura)
+
+In OpenXM specification, all servers are stack machines.
+These are called OpenXM stack machines.
+When a server ox\_xyz gets an OX data message,
+it translates the data into its own object and push the object
+on the stack.
+The translation scheme together with definitions of 
+mathematical operations
+of the system ox\_xyz is called the {\it phrase dictionary} of
+ox\_xyz following the OpenMath specification.
+
+Any OX command message starts with the int32 tag OX\_COMMAND.
+The body is OX stack machine operation code expressed by int32.
+The codes are listed below.
+\begin{verbatim}
+#define SM_popSerializedLocalObject               258
+#define SM_popCMO                                 262
+#define SM_popString                              263
+#define SM_mathcap                                264
+#define SM_pops                                   265
+#define SM_setName                                266
+#define SM_evalName                               267
+#define SM_executeStringByLocalParser             268
+#define SM_executeFunction                        269
+#define SM_beginBlock                             270
+#define SM_endBlock                               271
+#define SM_shutdown                               272
+#define SM_setMathCap                             273
+#define SM_executeStringByLocalParserInBatchMode  274
+#define SM_getsp                                  275
+#define SM_dupErrors                              276
+#define SM_DUMMY_sendcmo                          280
+#define SM_sync_ball                              281
+#define SM_control_kill                          1024
+#define SM_control_to_debug_mode                 1025
+#define SM_control_exit_debug_mode               1026
+#define SM_control_reset_connection              1030
+\end{verbatim}
+
+OpenXM does not have a standard for mathematical operation sets
+while it is a work in progress in \cite{gap}.
+Each OpenXM server has its own mathematical operation set.
+Mathematical operations are performed as follows.
+Mathematical operator name, such as fctr (asir factorization command),
+is pushed as a string,
+the stack machine command
+SM\_executeFunction (269) pops the operator name, the number of arguments
+and arguments, and
+the OX stack machine evaluates the operator, and pushes the result on the stack.
+For example, the following code factorizes $x^{100}-1$ by calling
+ox\_asir from asir.
+\begin{verbatim}
+P = ox_launch(); 
+ox_push_cmo(P,x^100-1); ox_push_cmo(P,ox_int32(1));
+ox_push_cmd(P,269); 
+Ans = ox_pop_cmo(P);
+\end{verbatim}
+
+When an error has occurred on an OpenXM server,
+an error object is pushed to the stack instead of a result of the computation.
+The error object consists of the serial number of the OX message
+which caused the error, and an error message.
+\begin{verbatim}
+[341] ox_rpc(0,"fctr",1.2*x)$
+[342] ox_pop_cmo(0);
+error([8,fctr : invalid argument])
+\end{verbatim}
+
+Errors are not sent to the client except a SM\_pop* command is received.
+OX stackmachines works in the asynchronous mode which is similar 
+to X servers.
+For servers for graphic applications, it is an advantageous feature.
+It is also easy to emulate RPC and a web server for MCP \cite{iamc} 
+on our asynchronous OX stackmachines.
+
+
+
+
+