Initial version

code/userprog/syscall.h

@@ -0,0 +1,135 @@
+/* syscalls.h 
+ * 	Nachos system call interface.  These are Nachos kernel operations
+ * 	that can be invoked from user programs, by trapping to the kernel
+ *	via the "syscall" instruction.
+ *
+ *	This file is included by user programs and by the Nachos kernel. 
+ *
+ * Copyright (c) 1992-1993 The Regents of the University of California.
+ * All rights reserved.  See copyright.h for copyright notice and limitation 
+ * of liability and disclaimer of warranty provisions.
+ */
+
+#ifndef SYSCALLS_H
+#define SYSCALLS_H
+
+#include "copyright.h"
+
+#define USER_START_ADDRESS 0x80
+
+/* system call codes -- used by the stubs to tell the kernel which system call
+ * is being asked for
+ */
+#define SC_Halt		0
+#define SC_Exit		1
+#define SC_Exec		2
+#define SC_Join		3
+#define SC_Create	4
+#define SC_Open		5
+#define SC_Read		6
+#define SC_Write	7
+#define SC_Close	8
+#define SC_Fork		9
+#define SC_Yield	10
+
+#ifdef IN_USER_MODE
+
+// LB: This part is read only on compiling the test/*.c files.
+// It is *not* read on compiling test/start.S
+
+
+/* The system call interface.  These are the operations the Nachos
+ * kernel needs to support, to be able to run user programs.
+ *
+ * Each of these is invoked by a user program by simply calling the 
+ * procedure; an assembly language stub stuffs the system call code
+ * into a register, and traps to the kernel.  The kernel procedures
+ * are then invoked in the Nachos kernel, after appropriate error checking, 
+ * from the system call entry point in exception.cc.
+ */
+
+/* Stop Nachos, and print out performance stats */
+void Halt () __attribute__ ((__noreturn__));
+
+
+/* Address space control operations: Exit, Exec, and Join */
+
+/* This user program is done (status = 0 means exited normally). */
+void Exit (int status) __attribute__ ((__noreturn__));
+
+/* A unique identifier for an executing user program (address space) */
+typedef int SpaceId;
+
+/* Run the executable, stored in the Nachos file "name", and return the 
+ * address space identifier
+ */
+SpaceId Exec (const char *name);
+
+/* Only return once the the user program "id" has finished.  
+ * Return the exit status.
+ */
+int Join (SpaceId id);
+
+
+/* File system operations: Create, Open, Read, Write, Close
+ * These functions are patterned after UNIX -- files represent
+ * both files *and* hardware I/O devices.
+ *
+ * If this assignment is done before doing the file system assignment,
+ * note that the Nachos file system has a stub implementation, which
+ * will work for the purposes of testing out these routines.
+ */
+
+/* A unique identifier for an open Nachos file. */
+typedef int OpenFileId;
+
+/* when an address space starts up, it has two open files, representing 
+ * keyboard input and display output (in UNIX terms, stdin and stdout).
+ * Read and Write can be used directly on these, without first opening
+ * the console device.
+ */
+
+#define ConsoleInput	0
+#define ConsoleOutput	1
+
+/* Create a Nachos file, with "name" */
+void Create (const char *name);
+
+/* Open the Nachos file "name", and return an "OpenFileId" that can 
+ * be used to read and write to the file.
+ */
+OpenFileId Open (const char *name);
+
+/* Write "size" bytes from "buffer" to the open file. */
+void Write (const void *buffer, int size, OpenFileId id);
+
+/* Read "size" bytes from the open file into "buffer".  
+ * Return the number of bytes actually read -- if the open file isn't
+ * long enough, or if it is an I/O device, and there aren't enough 
+ * characters to read, return whatever is available (for I/O devices, 
+ * you should always wait until you can return at least one character).
+ */
+int Read (void *buffer, int size, OpenFileId id);
+
+/* Close the file, we're done reading and writing to it. */
+void Close (OpenFileId id);
+
+
+
+/* User-level thread operations: Fork and Yield.  To allow multiple
+ * threads to run within a user program. 
+ */
+
+/* Fork a thread to run a procedure ("func") in the *same* address space 
+ * as the current thread.
+ */
+void Fork (void (*func) ());
+
+/* Yield the CPU to another runnable thread, whether in this address space 
+ * or not. 
+ */
+void Yield ();
+
+#endif // IN_USER_MODE
+
+#endif /* SYSCALL_H */