133 lines
3 KiB
Text
133 lines
3 KiB
Text
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.TH PC 1
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.SH NAME
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pc \- programmer's calculator
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.SH SYNOPSYS
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.B pc
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[
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.B -n
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]
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.SH DESCRIPTION
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.I Pc
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is an arbitrary precision calculator with a special emphasis on supporting two's complement bit operations and working with different number bases.
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.PP
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.I Pc
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reads input statements which are either expressions or control statements.
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Multiple statements in one line can be separated by semicolons.
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.I Pc
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prints the value of all expressions that are not terminated by a semicolon.
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.PP
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Expressions can use the C-like operators
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.TP
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.B + - * ** \fR(exponentiation\fR)
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.TP
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.B / % \fR(Euclidean division, by default\fR)
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.TP
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.B "& | ^ ~ ! << >>"
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.TP
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.B "&& || \fR(returning the second argument, if appropriate)"
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.TP
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.B < >= < <= == !=
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.PP
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Variables can be defined using
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.BR = .
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The builtin variable
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.B @
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always refers to the last printed result.
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.PP
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Numbers can use the prefixes
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.B 0b
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(binary),
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.B 0
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(octal),
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.B 0d
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(decimal) and
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.B 0x
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(hexadecimal).
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.B _
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in numbers can be added for readability and is ignored.
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.SS Builtin functions
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.TF xtend(n,m)
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.TP
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.I bin(n)
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Display \fIn\fR in binary.
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.TP
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.I oct(n)
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Display \fIn\fR in octal.
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.TP
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.I dec(n)
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Display \fIn\fR in decimal.
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.TP
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.I hex(n)
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Display \fIn\fR in hexadecimal.
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.TP
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.I abs(n)
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Absolute value of \fIn\fR.
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.TP
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.I round(n,m)
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\fIn\fR rounded to the nearest multiple of \fIm\fR.
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Numbers exactly halfway between are rounded to the next even multiple.
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.TP
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.I floor(n,m)
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\fIn\fR rounded down to the next multiple of \fIm\fR.
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.TP
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.I ceil(n,m)
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\fIn\fR rounded up to the next multiple of \fIm\fR.
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.TP
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.I trunc(n,m)
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\fIn\fR truncated to \fIm\fR bits.
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.TP
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.I xtend(n,m)
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\fIn\fR truncated to \fIm\fR bits, with the highest bit interpreted as a sign bit.
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.TP
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.I ubits(n)
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The minimum number of bits required to represent \fIn\fR as an unsigned number.
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.TP
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.I sbits(n)
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The minimum number of bits required to represent \fIn\fR as an signed number.
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.SS Control statements
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.PP
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Control statements are always evaluated with default input base 10.
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.TP
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\fL_\fR \fIn\fR
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If \fIn\fR ≠ 0, insert
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.B _
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in all printed numbers, every
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.I n
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digits.
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.TP
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\fL<\fR \fIn\fR
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Set the default input base to \fIn\fR (default 10).
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The input base can always be overriden by the base prefixes defined above.
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.TP
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\fL>\fR \fIn\fR
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Set the output base to \fIn\fR.
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If \fIn\fR = 0 (default), print each number in the base it was input in.
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.TP
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\fL/\fR 0
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Use Euclidean division (default).
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\fIa\fR / \fIb\fR is rounded towards ±∞ (opposite sign as \fIb\fR).
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\fIa\fR % \fIb\fR is always non-negative.
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.TP
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\fL/\fR 1
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Use truncating division (same as C).
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\fIa\fR / \fIb\fR is rounded towards zero.
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\fIa\fR % \fIb\fR can be negative.
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.SH SOURCE
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.B /sys/src/cmd/pc.y
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.SH "SEE ALSO"
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.IR bc (1),
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.IR hoc (1)
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.SH BUGS
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With the input base set to 16, terms such as
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.B ABC
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are ambiguous.
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They are interpreted as numbers only if there is no function or variable of the same name.
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To force interpretation as a number, use the \fL0x\fR prefix.
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.PP
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Arbitrary bases should be supported, but are not supported by the
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.IR mp (2)
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string functions.
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.SH HISTORY
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.I Pc
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first appeared in 9front (August, 2016).
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