TMSI Tiny BASIC Summary
GENERAL
  input line    : 72 characters maximum
  output line   : 125 characters maximum
  numbers       : 16-bit integers, -32768 to +32767
  variables     : 26, named A to Z
  variablelist  : one or more variables, separated by commas (,)
  expressions   : one or more variables or numbers, separated by + - * /
  expressionlist: one or more expressions, separated by commas (,)
  relation      : = > < >= <= <> or ><
COMMANDS
  RUN [expressionlist]
                Begin BASIC program execution at first line number.
                Save expressionlist for first INPUT statements.
  LIST [expression][,expression]
                List entire program, or one line, or range of lines.
  NEW
                Clear the BASIC program from memory.
STATEMENTS
  REM [any comment]
                Remark: Used for comments; ignored during execution.
  [LET] variable = expresion
                Set variable equal to the value of the expression.
  IF expression relation expression [THEN] statement
                If relationship between expressions is true, then
                execute statement; otherwise skip the statement.
  GOTO expression
                Jump to line number given by value of expression.
  GOSUB expression
                Save line number of the following line, then GOTO
                line number given by value of expression.
  RET[URN]
                Return to line number saved by the last GOSUB.
  PR[INT] printlist
                Print values of expressions, characters between quotes
                (") verbatim. Comma (,) between items leaves no space.
                Semicolon (;) between items moves to next Tab stop.
  IN[PUT] variablelist
                Read and evauate expressions from the keyboard, and
                assign them to variables in the variablelist.
FUNCTIONS
  RND (expression, expression)
                Return a random number between the values of the two
                expressions (inclusive). Expressions must be positive.
  USR (expression [,expression] [,expression] )
                Call machine-language subroutine at address of first
                expression value, with second expression value in R8,
                and third expression value in RA. The value of the
                USR function is determined by the subroutine called.
  USR(6)        Read character from keyboard.
  USR(9,0,n)    Print character n.
  USR(20,a)     Peek: Read byte from memory address a.
  USR(24,a,m)   Poke: Write byte m into memory address a.
  USR(32)       Call IDIOT monitor
  USR(35,n,m)   Read 1802 flag pins EF1-EF4, and set/reset Q pin:
                If m=1, set Q; if m=-1, reset Q; if m=0 leave Q as-is.
                If n=0, read Q; if n=1 to 4, read EFn.
  USR(38,a,b)   Read/Write 1802 I/O ports:
                If a=1 to 7, writes byte b to output port 1-7.
                If a=9 to 15, reads byte from input port 1-7.