NAME

       spim - A MIPS32 Simulator

SYNTAX

       spim [-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
       -file file <args> -execute file <args> ]

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

       spim 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
                 exceptions.  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.

       -file file <args>
                 Load and execute the assembly code in the file with arguments <args>.

       -execute file <args>
                 Load and execute the MIPS executable (a.out) file with arguments <args>. Only works on  systems
                 using a MIPS processors.

BUGS

       Instruction opcodes cannot be used as labels.

SEE ALSO

       xspim(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), Microsoft Research.

                                                                                                         spim(1)