SAL (Simple Abstract Language)

  In the following, x must be a register or the label of an address in memory.
  However, y and z may be registe(y), labels or constants.
  (y) implies "contents of y".

                              1. INSTRUCTIONS

  Call      Arg 1     Arg 2     Arg3                  Operation

  add       x         y         z         (x) <- (y) + (z) 
  and       x         y         z         (x) <- (y) AND (z)
  b         label                         PC <- (label)
  beq       y         z         label     PC <- (label) if (y) = (z)
  beqz      y         label               PC <- (label) if (y) = 0
  bge       y         z         label     PC <- (label) if (y) >= (z)
  bgez      y         label               PC <- (label) if (y) >= 0
  bgt       y         z         label     PC <- (label) if (y) > (z)
  bgtz      y         label               PC <- (label) if (y) > 0
  ble       y         z         label     PC <- (label) if (y) <= (z)
  blez      y         label               PC <- (label) if (y) <= 0
  blt       y         z         label     PC <- (label) if (y) < (z)
  bltz      y         label               PC <- (label) if (y) < 0
  bne       y         z         label     PC <- (label) if (y) != (z)
  bnez      y         label               PC <- (label) if (y) != 0
  cvt       x         y                   x <- (y) with type conversion
  div       x         y         z         (x) = (y) DIV (z)
  done                                    stop running; return control to OS
  get       x                             (x) <- value typed on keyboard
  getc      x                             (x) <- ASCII code of 
                                                 value typed on keyboard
  j         label                         PC <- (label)
  la        x         label               (x) <- address of label
  move      x         y                   (x) <- (y)
  mul       x         y         z         (x) = (y) * (z)
  nop                                     no operation
  nor       x         y         z         (x) = (y) NOR (z)
  or        x         y         z         (x) = (y) OR (z)
  put       x                             write (x) to the screen
  putc      y                             write character with  
                                          ASCII code = (y) on the screen
  puts      string                        write (string) to the screen*
  rem       x         y         z         (x) <- (y) MOD (z)
  rol   	x         y         sa        (x) <- (y) rotated left by sa bits
  ror   	x         y         sa        (x) <- (y) rotated right by sa bits
  sll       x         y         sa        (x) <- (z) shifted left by sa bits
  sra       x         y         sa        (x) <- (z) shifted right by sa bits, 
                                          sign-extended
  srl       x         y         sa        (x) <- (z) shifted right by sa bits, 
                                          0-extended
  sub       x         y         z         (x) <- (y) - (z)
  xor       x         y         z         (x) <- (y) XOR (z)

*string must be NULL terminated, like a variable declared with a 
.asciiz directive

Reference: James Goodman and Karen Miller, "A Programmer's View of 
Computer Architecture" (Saunders College Publishing, 1993)

                         2. ASSEMBLER DIRECTIVES
                         
  .data                                    what follows are initial data
  .text                                    what follows are instructions
  
  label: .ascii string                     A string is placed in memory
                                           (one byte per character) starting
                                           at location label.  string is
                                           an ASCII string enclosed in double
                                           quotes (" ").
  label: .asciiz string                    A NULL-terminated string is placed 
                                           in memory (one byte per character) 
                                           starting at location label.  
                                           string is an ASCII string enclosed 
                                           in double quotes (" ").
  label: .byte value[:num_elements]        An ASCII character (initially
                                           containing value) is located at
                                           label.  A character value is 
                                           specified by enclosing the character
                                           in single quotes.
                                           value is an optional field;
                                           if it is omitted, then the word at
                                           label is initialized to 0.
                                           If num_elements is present, it 
                                           specifies the number of words to be
                                           allocated and initialized to value.
  label: .float value[:num_elements]       AN IEEE single-precision floating-
                                           point number (initially
                                           containing value) is located at
                                           label.  value is an optional field;
                                           if it is omitted, then the word at
                                           label is initialized to 0.
                                           If num_elements is present, it 
                                           specifies the number of bytes to be
                                           allocated and initialized to value.
  label: .space number_of_bytes            A section of memory consisting of
                                           number_of_bytes bytes and starting at
                                           location label is initialized and
                                           set aside.
  label: .word value[:num_elements]        2's complement integer (initially
                                           containing value) is located at
                                           label.  value is an optional field;
                                           if it is omitted, then the word at
                                           label is initialized to 0.
                                           If num_elements is present, it 
                                           specifies the number of bytes to be
                                           allocated and initialized to value.