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36 .\" @(#)dc.1 8.1 (Berkeley) 6/6/93
47 .Op Fl e Ar expression
52 is an arbitrary precision arithmetic package.
53 The overall structure of
56 a stacking (reverse Polish) calculator i.e.\&
57 numbers are stored on a stack.
58 Adding a number pushes it onto the stack.
59 Arithmetic operations pop arguments off the stack
63 utility, which is a preprocessor for
65 providing infix notation and a C-like syntax
66 which implements functions and reasonable control
67 structures for programs.
68 The options are as follows:
70 .It Fl e Ar expr , Fl Fl expression Ar expr
75 options are specified, they will be processed in the order given.
76 .It Fl f Ar filename , Fl Fl file Ar filename
77 Process the content of the given file before further calculations are done.
80 options are specified, they will be processed in the order given.
82 Print short usage info.
83 .It Fl V , Fl Fl version
86 Enable extended register mode.
89 to allow more than 256 registers.
92 for a more detailed description.
99 are specified on the command line,
101 reads from the standard input.
112 operates on decimal integers,
113 but one may specify an input base, output base,
114 and a number of fractional digits (scale) to be maintained.
115 Whitespace is ignored, except where it signals the end of a number,
116 end of a line or when a register name is expected.
117 The following constructions are recognized:
118 .Bl -tag -width "number"
120 The value of the number is pushed on the stack.
121 A number is an unbroken string of the digits 0\-9 and letters A\-F.
122 It may be preceded by an underscore
124 to input a negative number.
125 A number may contain a single decimal point.
126 A number may also contain the characters A\-F, with the values 10\-15.
127 .It Cm "+ - / * % ~ ^"
129 top two values on the stack are added
136 divided and remaindered (~),
137 or exponentiated (^).
138 The two entries are popped off the stack;
139 the result is pushed on the stack in their place.
140 Any fractional part of an exponent is ignored.
142 For addition and subtraction, the scale of the result is the maximum
143 of scales of the operands.
144 For division the scale of the result is defined
145 by the scale set by the
148 For multiplication, the scale is defined by the expression
149 .Sy min(a+b,max(a,b,scale)) ,
154 are the scales of the operands, and
156 is the scale defined by the
159 For exponentiation with a non-negative exponent, the scale of the result is
160 .Sy min(a*b,max(scale,a)) ,
163 is the scale of the base, and
168 If the exponent is negative, the scale of the result is the scale
173 In the case of the division and modulus operator (~),
174 the resultant quotient is pushed first followed by the remainder.
175 This is a shorthand for the sequence:
176 .Bd -literal -offset indent -compact
179 The division and modulus operator is a non-portable extension.
181 Pop the top value from the stack.
182 If that value is a number, compute the integer part of the number modulo 256.
183 If the result is zero, push an empty string.
184 Otherwise push a one character string by interpreting the computed value
189 If the top value is a string, push a string containing the first character
190 of the original string.
191 If the original string is empty, an empty string is pushed back.
194 operator is a non-portable extension.
196 All values on the stack are popped.
198 The top value on the stack is duplicated.
200 All values on the stack are printed, separated by newlines.
202 The top two numbers are popped from the stack and compared.
203 A one is pushed if the top of the stack is equal to the second number
205 A zero is pushed otherwise.
206 This is a non-portable extension.
208 Pushes the input base on the top of the stack.
210 The top value on the stack is popped and used as the
211 base for further input.
212 The initial input base is 10.
214 Pop the top value from the stack.
215 The recursion level is popped by that value and, following that,
216 the input is skipped until the first occurrence of the
221 operator is a non-portable extension, used by the
225 The current scale factor is pushed onto the stack.
227 The top of the stack is popped, and that value is used as
228 a non-negative scale factor:
229 the appropriate number of places
230 are printed on output,
231 and maintained during multiplication, division, and exponentiation.
232 The interaction of scale factor,
233 input base, and output base will be reasonable if all are changed
238 is treated as a stack and its top value is popped onto the main stack.
243 is pushed on the stack.
247 Initially, all registers contain the value zero.
254 operator is a non-portable extensions, used by the
258 The top of the stack is replaced by one if the top of the stack
260 If the top of the stack is unequal to zero, it is replaced by zero.
261 This is a non-portable extension.
263 The top value on the stack is popped and printed without a newline.
264 This is a non-portable extension.
266 Pushes the output base on the top of the stack.
268 The top value on the stack is popped and used as the
269 base for further output.
270 The initial output base is 10.
272 The top of the stack is popped.
273 If the top of the stack is a string, it is printed without a trailing newline.
274 If the top of the stack is a number, it is interpreted as a
275 base 256 number, and each digit of this base 256 number is printed as
278 character, without a trailing newline.
280 The top value on the stack is printed with a trailing newline.
281 The top value remains unchanged.
283 The top value on the stack is popped and the string execution level is popped
287 If executing a string, the recursion level is
290 The top of the stack is removed (popped).
291 This is a non-portable extension.
293 The top two values on the stack are reversed (swapped).
294 This is a non-portable extension.
298 is treated as a stack.
299 The top value of the main stack is popped and pushed on it.
302 top of the stack is popped and stored into
306 Replaces the top element on the stack by its square root.
307 The scale of the result is the maximum of the scale of the argument
308 and the current value of scale.
310 Replaces the number on the top of the stack with its scale factor.
311 If the top of the stack is a string, replace it with the integer 0.
313 Treats the top element of the stack as a character string
314 and executes it as a string of
318 Replaces the number on the top of the stack with its length.
319 The length of a string is its number of characters.
320 The length of a number is its number of digits, not counting the minus sign
323 The stack level is pushed onto the stack.
324 .It Cm \&[ Ns ... Ns Cm \&]
327 string onto the top of the stack.
328 If the string includes brackets, these must be properly balanced.
329 The backslash character
331 may be used as an escape character, making it
332 possible to include unbalanced brackets in strings.
333 To include a backslash in a string, use a double backslash.
342 The top two elements of the stack are popped and compared.
345 is executed if they obey the stated
348 .Cm < Ns Va x Ns e Ns Va y
349 .Cm > Ns Va x Ns e Ns Va y
350 .Cm = Ns Va x Ns e Ns Va y
351 .Cm !< Ns Va x Ns e Ns Va y
352 .Cm !> Ns Va x Ns e Ns Va y
353 .Cm != Ns Va x Ns e Ns Va y
355 These operations are variants of the comparison operations above.
356 The first register name is followed by the letter
358 and another register name.
361 will be executed if the relation is true, and register
363 will be executed if the relation is false.
364 This is a non-portable extension.
366 The top two numbers are popped from the stack and compared.
367 A one is pushed if the top of the stack is less than the second number
369 A zero is pushed otherwise.
370 This is a non-portable extension.
372 The top two numbers are popped from the stack and compared.
373 A one is pushed if the top of stack is less than or equal to the
374 second number on the stack.
375 A zero is pushed otherwise.
376 This is a non-portable extension.
378 Interprets the rest of the line as a
382 A line of input is taken from the input source (usually the terminal)
385 Pop two values from the stack.
386 The second value on the stack is stored into the array
388 indexed by the top of stack.
390 Pop a value from the stack.
391 The value is used as an index into register
393 The value in this register is pushed onto the stack.
395 Array elements initially have the value zero.
396 Each level of a stacked register has its own array associated with
399 .Bd -literal -offset indent
400 [first] 0:a [dummy] Sa [second] 0:a 0;a p La 0;a p
404 .Bd -literal -offset indent
411 is written in an array that is later popped, to reveal the array that
415 Skip the rest of the line.
416 This is a non-portable extension.
419 Registers have a single character name
423 may be any character, including space, tab or any other special character.
424 If extended register mode is enabled using the
426 option and the register identifier
428 has the value 255, the next two characters are interpreted as a
429 two-byte register index.
430 The set of standard single character registers and the set of extended
431 registers do not overlap.
432 Extended register mode is a non-portable extension.
434 An example which prints the first ten values of
436 .Bd -literal -offset indent
442 Independent of the current input base, the command
443 .Bd -literal -offset indent
447 will reset the input base to decimal 10.
450 .It %c (0%o) is unimplemented
451 an undefined operation was called.
453 for not enough elements on the stack to do what was asked.
454 .It stack register '%c' (0%o) is empty
457 operation from a stack register that is empty.
458 .It Runtime warning: non-zero scale in exponent
459 for a fractional part of an exponent that is being ignored.
461 for trying to divide by zero.
462 .It remainder by zero
463 for trying to take a remainder by zero.
464 .It square root of negative number
465 for trying to take the square root of a negative number.
467 for an array index that is larger than 2048.
469 for a negative array index.
470 .It "input base must be a number between 2 and 16"
471 for trying to set an illegal input base.
472 .It output base must be a number greater than 1
473 for trying to set an illegal output base.
474 .It scale must be a nonnegative number
475 for trying to set a negative or zero scale.
477 for trying to set a scale that is too large.
478 A scale must be representable as a 32-bit unsigned number.
479 .It Q command argument exceeded string execution depth
480 for trying to pop the recursion level more than the current
482 .It Q command requires a number >= 1
483 for trying to pop an illegal number of recursion levels.
484 .It recursion too deep
485 for too many levels of nested execution.
487 The recursion level is increased by one if the
491 operation or one of the compare operations resulting in the execution
492 of register is executed.
493 As an exception, the recursion level is not increased if the operation
494 is executed as the last command of a string.
495 For example, the commands
496 .Bd -literal -offset indent
501 will execute an endless loop, while the commands
502 .Bd -literal -offset indent
507 will terminate because of a too deep recursion level.
508 .It J command argument exceeded string execution depth
509 for trying to pop the recursion level more than the current
512 for a failed scan for an occurrence of the
522 "DC \- An Interactive Desk Calculator"
523 .Pa /usr/share/doc/usd/05.dc/ .
525 The arithmetic operations of the
527 utility are expected to conform to the definition listed in the
535 command first appeared in
537 A complete rewrite of the
541 big number routines first appeared in
545 The original version of the
547 command was written by
551 The current version of the
553 utility was written by