projects / unix-history / blame
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1 | .\" Copyright (c) 1983 Regents of the University of California. |
| 2 | .\" All rights reserved. The Berkeley software License Agreement | |
| 3 | .\" specifies the terms and conditions for redistribution. | |
| 4 | .\" | |
| 95f51977 | 5 | .\" @(#)bit.3f 6.4 (Berkeley) 4/30/86 |
| 4ec885fb | 6 | .\" |
| 95f51977 | 7 | .TH BIT 3F "April 30, 1986" |
| 4ec885fb KM |
8 | .UC 5 |
| 9 | .SH NAME | |
| 10 | bit \- and, or, xor, not, rshift, lshift bitwise functions | |
| 11 | .SH SYNOPSIS | |
| 12 | .B (intrinsic) function and (word1, word2) | |
| 13 | .sp 1 | |
| 14 | .B (intrinsic) function or (word1, word2) | |
| 15 | .sp 1 | |
| 16 | .B (intrinsic) function xor (word1, word2) | |
| 17 | .sp 1 | |
| 18 | .B (intrinsic) function not (word) | |
| 19 | .sp 1 | |
| 20 | .B (intrinsic) function rshift (word, nbits) | |
| 21 | .sp 1 | |
| 22 | .B (intrinsic) function lshift (word, nbits) | |
| 23 | .SH DESCRIPTION | |
| 24 | These bitwise functions are built into the compiler and return | |
| 25 | the data type of their argument(s). | |
| 9f694ead | 26 | Their arguments must be |
| 4ec885fb | 27 | .B integer |
| 9f694ead RE |
28 | or |
| 29 | .B logical | |
| 30 | values. | |
| 4ec885fb KM |
31 | .PP |
| 32 | The bitwise combinatorial functions return the | |
| 33 | bitwise ``and'' (\fBand\fR), ``or'' (\fBor\fR), or ``exclusive or'' (\fBxor\fR) | |
| 34 | of two operands. | |
| 35 | .B Not | |
| 36 | returns the bitwise complement of its operand. | |
| 37 | .PP | |
| 38 | .IR Lshift , | |
| 39 | or | |
| 40 | .I rshift | |
| 41 | with a negative | |
| 42 | .IR nbits , | |
| 43 | is a logical left shift with no end around carry. | |
| 44 | .IR Rshift , | |
| 45 | or | |
| 46 | .I lshift | |
| 47 | with a negative | |
| 48 | .IR nbits , | |
| 26b5771b | 49 | is an arithmetic right shift with sign extension. |
| 4ec885fb KM |
50 | No test is made for a reasonable value of |
| 51 | .I nbits. | |
| 9f694ead RE |
52 | .PP |
| 53 | These functions may be used to create a variety of general routines, as in | |
| 54 | the following statement function definitions: | |
| 55 | .sp 1 | |
| 56 | .B integer bitset, bitclr, getbit, word, bitnum | |
| 57 | .sp 1 | |
| 58 | .B bitset( word, bitnum ) = or(word,lshift(1,bitnum)) | |
| 59 | .br | |
| 60 | .B bitclr( word, bitnum ) = and(word,not(lshift(1,bitnum))) | |
| 61 | .br | |
| 62 | .B getbit( word, bitnum ) = and(rshift(word,bitnum),1) | |
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63 | .SH FILES |
| 64 | These functions are generated in-line by the f77 compiler. |