config

Calc Software Package for Number Calc

    =-=

    config("redc2", int)

    Redc2 specifies the sizes of numbers at which calc switches from
    its first to its second algorithm when using the REDC algorithm.
    The first algorithm performs a multiply and a modular reduction
    together in one loop which runs in O(N^2).	The second algorithm
    does the REDC calculation using three multiplies, and runs in
    O(N^1.585).	 The argument for redc2 is the size of the modulus at
    which the second algorithm begins to be used.

    Units refer to internal calculation digits where each digit
    is BASEB bits in length.  The value of BASEB is returned by
    config("baseb").

    The default value for config("redc2") is 220.  This default was
    established as 5/4 (the historical ratio of config("pow2") to
    config("pow2")) of the config("pow2") value.  This means that if
    config("baseb") is 32, then by default numbers up to (220*32)+31 =
    7071 bits in length (< 2128 decimal digits) use the REDC algorithm,
    for calculating powers modulo another number.

    A value of zero resets the parameter back to their default values.

    The value of 1 and values < 0 are reserved for future use.

    Usually there is no need to change these parameters.

    =-=

    config("tilde", boolean)

    Config("tilde") controls whether or not a leading tilde ('~') is
    printed to indicate that a number has not been printed exactly
    because the number of decimal digits required would exceed the
    specified maximum number.  The initial "tilde" value is 1.

    =-=

    config("tab", boolean)

    Config ("tab") controls the printing of a tab before results
    automatically displayed when working interactively.	 It does not
    affect the printing by the functions print, printf, etc.  The initial
    "tab" value is 1.

    =-=

    config("quomod", bitflag)
    config("quo", bitflag)
    config("mod", bitflag)
    config("sqrt", bitflag)
    config("appr", bitflag)
    config("cfappr", bitflag)
    config("cfsim", bitflag)
    config("outround", bitflag)
    config("round", bitflag)

    The "quomod", "quo", "mod", "sqrt", "appr", "cfappr", "cfsim", and
    "round" control the way in which any necessary rounding occurs.
    Rounding occurs when for some reason, a calculated or displayed
    value (the "approximation") has to differ from the "true value",
    e.g. for quomod and quo, the quotient is to be an integer, for sqrt
    and appr, the approximation is to be a multiple of an explicit or
    implicit "epsilon", for round and bround (both controlled by
    config("round")) the number of decimal places or fractional bits
    in the approximation is limited.  Zero value for any of these
    parameters indicates that the true value is greater than the approximation,
    i.e. the rounding is "down", or in the case of mod, that the
    residue has the same sign as the divisor.  If bit 4 of the
    parameter is set, the rounding of to the nearest acceptable candidate
    when this is uniquely determined; in the remaining ambiguous cases,
    the type of rounding is determined by the lower bits of the parameter
    value.  If bit 3 is set, the rounding for quo, appr and sqrt,
    is to the nearest even integer or the nearest even multiple of epsilon,
    and for round to the nearest even "last decimal place".  The effects
    of the 3 lowest bits of the parameter value are as follows:

	Bit 0: Unconditional reversal (down to up, even to odd, etc.)
	Bit 1: Reversal if the exact value is negative
	Bit 2: Reversal if the divisor or epsilon is negative

    (Bit 2 is irrelevant for the functions round and bround since the
    equivalent epsilon (a power of 1/10 or 1/2) is always positive.)

    For quomod, the quotient is rounded to an integer value as if
    evaluating quo with config("quo") == config("quomod").  Similarly,
    quomod and mod give the same residues if config("mod") == config("quomod").

    For the sqrt function, if bit 5 of config("sqrt") is set, the exact
    square-root is returned when this is possible; otherwise the
    result is rounded to a multiple of epsilon as determined by the
    five lower order bits.  Bit 6 of config("sqrt") controls whether the
    principal or non-principal square-root is returned.

    For the functions cfappr and cfsim, whether the "rounding" is down
    or up, etc. is controlled by the appropriate bits of config("cfappr")
    and config("cfsim") as for quomod, quo, etc.

    The "outround" parameter determines the type of rounding to be used
    by the various kinds of printing to the output: bits 0, 1, 3 and 4
    are used in the same way as for the functions round and bround.

    The C language method of modulus and integer division is:

	    config("quomod", 2)
	    config("quo", 2)
	    config("mod", 2)

    =-=

    config("leadzero", boolean)

    The "leadzero" parameter controls whether or not a 0 is printed
    before the decimal point in non-zero fractions with absolute value
    less than 1, e.g. whether 1/2 is printed as 0.5 or .5.   The
    initial value is 0, corresponding to the printing .5.

    =-=

    config("fullzero", boolean)

    The "fullzero" parameter controls whether or not in decimal floating-
    point printing, the digits are padded with zeros to reach the
    number of digits specified by config("display") or by a precision
    specification in formatted printing.  The initial value for this
    parameter is 0, so that, for example, if config("display") >= 2,
    5/4 will print in "real" mode as 1.25.

    =-=

    config("maxscan", int)

    The maxscan value controls how many scan errors are allowed
    before the compiling phase of a computation is aborted.  The initial
    value of "maxscan" is 20.  Setting maxscan to 0 disables this feature.

    =-=

    config("prompt", str)

    The default prompt when in interactive mode is "> ".  One may change
    this prompt to a more cut-and-paste friendly prompt by:

	    config("prompt", "; ")

    On windowing systems that support cut/paste of a line, one may
    cut/copy an input line and paste it directly into input.  The
    leading ';' will be ignored.

    =-=

    config("more", str)

    When inside multi-line input, the more prompt is used.  One may
    change it by:

	    config("more", ";; ")

    =-=

    config("blkmaxprint", int)

    The "blkmaxprint" config value limits the number of octets to print
    for a block.  A "blkmaxprint" of 0 means to print all octets of a
    block, regardless of size.

    The default is to print only the first 256 octets.

    =-=

    config("blkverbose", boolean)

    The "blkverbose" determines if all lines, including duplicates
    should be printed.	If TRUE, then all lines are printed.  If false,
    duplicate lines are skipped and only a "*" is printed in a style
    similar to od.  This config value has not meaning if "blkfmt" is "str".

    The default value for "blkverbose" is FALSE: duplicate lines are
    not printed.

    =-=

    config("blkbase", "blkbase_string")

    The "blkbase" determines the base in which octets of a block
    are printed.  Possible values are:

	"hexadecimal"		Octets printed in 2 digit hex
	"hex"
	"default"

	"octal"			Octets printed in 3 digit octal
	"oct"

	"character"		Octets printed as chars with non-printing
	"char"			    chars as \123 or \n, \t, \r

	"binary"		Octets printed as 0 or 1 chars
	"bin"

	"raw"			Octets printed as is, i.e. raw binary
	"none"

    Where multiple strings are given, the first string listed is what
    config("blkbase") will return.

    The default "blkbase" is "hexadecimal".

    =-=

    config("blkfmt", "blkfmt_string")

    The "blkfmt" determines for format of how block are printed:

	"lines"		print in lines of up to 79 chars + newline
	"line"

	"strings"	print as one long string
	"string"
	"str"

	"od_style"	print in od-like format, with leading offset,
	"odstyle"	   followed by octets in the given base
	"od"

	"hd_style"	print in hex dump format, with leading offset,
	"hdstyle"	   followed by octets in the given base, followed
	"hd"		   by chars or '.' if no-printable or blank
	"default"

    Where multiple strings are given, the first string listed is what
    config("blkfmt") will return.

    The default "blkfmt" is "hd_style".

    =-=

    config("calc_debug", bitflag)

    The "calc_debug" is intended for controlling internal calc routines
    that test its operation, or collect or display information that
    might be useful for debug purposes.	 Much of the output from these
    will make sense only to calc wizards.   Zero value (the default for
    both oldstd and newstd) of config("resource_debug") corresponds to
    switching off all these routines.  For nonzero value, particular
    bits currently have the following meanings:

	n		Meaning of bit n of config("calc_debug")

	0	outputs shell commands prior to execution

	1	outputs currently active functions when a quit instruction
		is executed

	2	some details of shs, shs1 and md5 hash states are included
		in the output when these are printed

	3	when a function constructs a block value, tests are
		made that the result has the properties required for use of
		that block, e.g. that the pointer to the start of the
		block is not NULL, and that its "length" is not negative.
		A failure will result in a runtime error.

	4	Report on changes to the state of stdin as well as changes
		to internal variables that control the setting and restoring
		of stdin.

	5	Report on changes to the run state of calc.

	6	Report on rand() subtractive 100 shuffle generator issues.

    Bits >= 7 are reserved for future use and should not be used at this time.

    By default, "calc_debug" is 0.  The initial value may be overridden
    by the -D command line option.

    =-=

    config("resource_debug", bitflag)
    config("lib_debug", bitflag)

    The "resource_debug" parameter is intended for controlling the possible
    display of special information relating to functions, objects, and
    other structures created by instructions in calc scripts.
    Zero value of config("resource_debug") means that no such information
    is displayed.  For other values, the non-zero bits which currently
    have meanings are as follows:

	n		Meaning of bit n of config("resource_debug")

	0	When a function is defined, redefined or undefined at
		interactive level, a message saying what has been done
		is displayed.

	1	When a function is defined, redefined or undefined during
		the reading of a file, a message saying what has been done
		is displayed.

	2	Show func will display more information about a functions
		arguments and argument summary information.

	3	During execution, allow calc standard resource files
		to output additional debugging information.

    The value for config("resource_debug") in both oldstd and newstd
    is 3, but if calc is invoked with the -d flag, its initial value
    is zero.  Thus, if calc is started without the -d flag, until
    config("resource_debug") is changed, a message will be output when
    a function is defined either interactively or during the reading of
    a file.

    The name config("lib_debug") is equivalent to config("resource_debug")
    and is included for backward compatibility.

    By default, "resource_debug" is 3.	The -d flag changes this default to 0.
    The initial value may be overridden by the -D command line option.

    =-=

    config("user_debug", int)

    The "user_debug" is provided for use by users.  Calc ignores this value
    other than to set it to 0 by default (for both "oldstd" and "newstd").
    No calc code or standard resource should change this value.	 Users
    should feel free to use it in any way.   In particular they may