spim(1) 						      General Commands Manual							   spim(1)

NAME

       xspim - A MIPS32 Simulator

SYNTAX

       xspim [-asm/-bare      -exception/-noexception	   -quiet/-noquiet	-mapped_io/-nomapped_io
       -delayed_branches      -delayed_loads
       -stext size	-sdata size	 -sstack size	   -sktext size      -skdata size      -ldata size	-lstack size	  -lkdata size
	    -hexgpr/-nohexgpr	   -hexfpr/-nohexfpr]
       -file file -execute file

DESCRIPTION

       SPIM  S20  is a simulator that runs programs for the MIPS32 RISC computers. SPIM can read and immediately execute files containing assembly
       language or MIPS executable files.  SPIM is a self-contained system for running these programs and contains a debugger and interface  to  a
       few operating system services.

       SPIM  comes  in	two versions.  The plain version is called spim.  It runs on any type of terminal.  It operates like most programs of this
       type: you type a line of text, hit the return key, and spim executes your command.  The fancier version of SPIM is called xspim.   It  uses
       the  X-window  system,  so you must have a bit-mapped display to run it.  xspim, however, is a much easier program to learn and use because
       its commands are always visible on the screen and because it continually displays the machine's registers.

OPTIONS

       xspim has many options:

       -asm	 Simulate the virtual MIPS machine provided by the assembler.  This is the default.

       -bare	 Simulate a bare MIPS machine without pseudo-instructions or the additional addressing modes provided by the  assembler.   Implies
		 -quiet.

       -exception
		 Load the standard exception handler and startup code.	This is the default.

       -noexception
		 Do  not  load	the  standard  exception  handler and startup code.  This exception handler handles exceptions.  When an exception
		 occurs, SPIM jumps to location 0x80000080, which must contain code to service the exception.  In  addition,  this  file  contains
		 startup  code	that  invokes  the  routine  main.   Without the startup routine, SPIM begins execution at the instruction labeled
		 __start.

       -quiet	 Print a message when an exception occurs.  This is the default.

       -noquiet  Do not print a message at exceptions.

       -mapped_io
		 Enable the memory-mapped IO facility.	Programs that use SPIM syscalls to read from the terminal cannot  also	use  memory-mapped
		 IO.

       -nomapped_io
		 Disable the memory-mapped IO facility.

       -delayed_branches
		 Simulate MIPS's delayed control transfers by executing the instruction after a branch, jump, or call before transferring control.
		 SPIM's default is to simulate non-delayed transfers, unless the -bare flag is set.

       -delayed_loads
		 Simulate MIPS's original, non-interlocked load instructions.  SPIM's default is to simulate non-delayed loads, unless	the  -bare
		 flag is set.

       -stext size -sdata size -sstack size -sktext size -skdata size
		 Sets  the  initial  size  of  memory  segment seg to be size bytes.  The memory segments are named: text, data, stack, ktext, and
		 kdata.  The text segment contains instructions from a program.  The data segment holds the program's  data.   The  stack  segment
		 holds	its  runtime  stack.   In addition to running a program, SPIM also executes system code that handles interrupts and excep-
		 tions.  This code resides in a separate part of the address space called  the	kernel.   The  ktext  segment  holds  this  code's
		 instructions and kdata holds its data.  There is no kstack segment since the system code uses the same stack as the program.  For
		 example, the pair of arguments -sdata 2000000 starts the user data segment at 2,000,000 bytes.

       -ldata size -lstack size  -lkdata size
		 Sets the limit on how large memory segment seg can grow to be size bytes.  The memory segments that can grow are data, stack, and
		 kdata.

       -hexgpr	 Disply the general purpose registers (GPRs) in hexadecimal.

       -nohexgpr Disply the general purpose registers (GPRs) in decimal.

       -hexfpr	 Disply the floating-point registers (FPRs) in hexadecimal.

       -nohexfpr Disply the floating-point registers (FPRs) as floating-point values

       -file file 10
		 Load and execute the assembly code in the file.

       -execute file 10
		 Load and execute the MIPS executable (a.out) file.  Only works on systems using a MIPS processors.

BUGS

       Instruction opcodes cannot be used as labels.

SEE ALSO

       spim(1)
       James R. Larus, ``SPIM S20: A MIPS R2000 Simulator,'' included with SPIM distribution.

AUTHOR

       James  R.  Larus, Computer Sciences Department, University of Wisconsin-Madison.  Current address: James R Larus (larus@microsoft.com), Mi-
       crosoft Research.

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