557:
546:
32:
490:. Most C and C++ implementations, and Go, choose which right shift to perform depending on the type of integer being shifted: signed integers are shifted using the arithmetic shift, and unsigned integers are shifted using the logical shift. In particular, C++ uses its logical shift operators as part of the syntax of its input and output functions, called "cin" and "cout" respectively.
493:
All currently relevant C standards (ISO/IEC 9899:1999 to 2011) leave a definition gap for cases where the number of shifts is equal to or bigger than the number of bits in the operands in a way that the result is undefined. This helps allow C compilers to emit efficient code for various platforms by
168:(mantissa); every bit in the operand is simply moved a given number of bit positions, and the vacant bit-positions are filled, usually with zeros, and possibly ones (contrast with a
693:
669:
723:
115:
842:
526:
300:
53:
49:
96:
364:
356:
249:
68:
283:
232:
449:
275:
253:
75:
494:
allowing direct use of the native shift instructions which have differing behavior. For example, shift-left-word in
837:
199:
753:
42:
483:
228:
585:
475:
271:
220:
82:
701:
445:
64:
498:
chooses the more-intuitive behavior where shifting by the bit width or above gives zero, whereas SHL in
360:
472:
433:
bits on a signed or unsigned binary number has the effect of multiplying it by 2. Shifting right by
148:. This is further modulated by the number of bit positions a given value shall be shifted, such as
425:
Logical shifts can be useful as efficient ways to perform multiplication or division of unsigned
20:
525:(LLVM). Others choose to specify the behavior of their most common target platforms, such as
390:
137:
731:
444:
Logical right shift differs from arithmetic right shift. Thus, many languages have different
157:
129:
537:
If the bit sequence 0001 0111 (decimal 23) is logically shifted by one bit position, then:
89:
805:
556:
510:
169:
545:
831:
352:
779:
645:
160:, a logical shift does not preserve a number's sign bit or distinguish a number's
621:
237:
165:
31:
453:
368:
279:
216:
176:
161:
183:
Logical shift operators in various programming languages and processors
495:
441:
binary number has the effect of dividing it by 2 (rounding towards 0).
426:
407:
318:
241:
140:
that shifts all the bits of its operand. The two base variants are the
468:), because left shift via logic and arithmetic have the same effect.)
175:
A logical shift is often used when its operand is being treated as a
19:"shift left" redirects here. For the software testing practice, see
479:
224:
555:
544:
335:
506:, and as such a shift by the bit width doesn't change the value.
514:
386:
670:"Operator Expressions: Arithmetic and Logical Binary Operators"
603:
568:
Note: MSB = Most
Significant Bit, LSB = Least Significant Bit
499:
245:
25:
504:
to reduce the maximum execution time of the instructions
604:"Set - Environment Variable - Windows CMD - SS64.com"
502:chooses to mask the shift amount to the lower bits
56:. Unsourced material may be challenged and removed.
780:"LLVM Language Reference Manual - shl Instruction"
517:, also leave shifting by the bit width and above
486:, however, have only one right shift operator,
460:, but the arithmetic right shift operator is
8:
554:Shift right yields: 0000 1011 (decimal 11)
543:Shift left yields: 0010 1110 (decimal 46)
464:. (Java has only one left shift operator (
116:Learn how and when to remove this message
181:
577:
456:, the logical right shift operator is
385:VHSIC Hardware Description Language (
7:
54:adding citations to reliable sources
429:by powers of two. Shifting left by
806:"<< Operator (C# Reference)"
529:which specifies the x86 behavior.
14:
622:"BitwiseOperators - Python Wiki"
179:of bits instead of as a number.
30:
724:"x86 Instruction Set Reference"
41:needs additional citations for
694:"PowerPC Instruction Set: slw"
1:
509:Some languages, such as the
16:Bit-level computer operation
560:Logical right shift one bit
859:
549:Logical left shift one bit
448:for them. For example, in
18:
646:"Shl in std::ops - Rust"
586:"The Package Interfaces"
843:Operators (programming)
561:
550:
235:(unsigned types only);
559:
548:
473:programming languages
303:(unsigned types only)
256:(unsigned types only)
188:Language or processor
50:improve this article
754:"Opcodes.Shl Field"
734:on 19 February 2018
704:on 4 September 2014
184:
146:logical right shift
810:msdn.microsoft.com
758:msdn.microsoft.com
728:x86.renejeschke.de
698:pds.twi.tudelft.nl
562:
551:
182:
142:logical left shift
21:shift-left testing
838:Binary arithmetic
674:doc.rust-lang.org
650:doc.rust-lang.org
566:
565:
423:
422:
138:bitwise operation
126:
125:
118:
100:
850:
822:
821:
819:
817:
802:
796:
795:
793:
791:
776:
770:
769:
767:
765:
750:
744:
743:
741:
739:
730:. Archived from
720:
714:
713:
711:
709:
700:. Archived from
690:
684:
683:
681:
680:
666:
660:
659:
657:
656:
642:
636:
635:
633:
632:
618:
612:
611:
600:
594:
593:
582:
540:
539:
489:
467:
463:
459:
419:
414:
402:
397:
380:
375:
347:
342:
330:
325:
313:
308:
295:
290:
266:
261:
211:
206:
185:
158:arithmetic shift
154:shift right by n
130:computer science
121:
114:
110:
107:
101:
99:
58:
34:
26:
858:
857:
853:
852:
851:
849:
848:
847:
828:
827:
826:
825:
815:
813:
804:
803:
799:
789:
787:
778:
777:
773:
763:
761:
752:
751:
747:
737:
735:
722:
721:
717:
707:
705:
692:
691:
687:
678:
676:
668:
667:
663:
654:
652:
644:
643:
639:
630:
628:
626:wiki.python.org
620:
619:
615:
602:
601:
597:
584:
583:
579:
574:
535:
487:
465:
461:
457:
417:
412:
400:
395:
378:
373:
345:
340:
328:
323:
311:
306:
293:
288:
264:
259:
236:
209:
204:
150:shift left by 1
122:
111:
105:
102:
65:"Logical shift"
59:
57:
47:
35:
24:
17:
12:
11:
5:
856:
854:
846:
845:
840:
830:
829:
824:
823:
797:
786:. LLVM Project
771:
745:
715:
685:
661:
637:
613:
595:
576:
575:
573:
570:
564:
563:
552:
534:
531:
511:.NET Framework
421:
420:
415:
410:
404:
403:
398:
393:
382:
381:
376:
371:
349:
348:
343:
338:
332:
331:
326:
321:
315:
314:
309:
304:
297:
296:
291:
286:
268:
267:
262:
257:
213:
212:
207:
202:
196:
195:
192:
189:
170:circular shift
124:
123:
38:
36:
29:
15:
13:
10:
9:
6:
4:
3:
2:
855:
844:
841:
839:
836:
835:
833:
811:
807:
801:
798:
785:
781:
775:
772:
759:
755:
749:
746:
733:
729:
725:
719:
716:
703:
699:
695:
689:
686:
675:
671:
665:
662:
651:
647:
641:
638:
627:
623:
617:
614:
609:
605:
599:
596:
591:
590:www.adaic.org
587:
581:
578:
571:
569:
558:
553:
547:
542:
541:
538:
532:
530:
528:
524:
520:
516:
512:
507:
505:
501:
497:
491:
485:
481:
477:
474:
469:
455:
451:
447:
442:
440:
436:
432:
428:
416:
411:
409:
406:
405:
399:
394:
392:
388:
384:
383:
377:
372:
370:
366:
362:
358:
354:
353:Object Pascal
351:
350:
344:
339:
337:
334:
333:
327:
322:
320:
317:
316:
310:
305:
302:
299:
298:
294:>>>
292:
287:
285:
281:
277:
273:
270:
269:
263:
258:
255:
251:
247:
243:
239:
234:
230:
226:
222:
218:
215:
214:
208:
203:
201:
198:
197:
193:
190:
187:
186:
180:
178:
173:
171:
167:
163:
159:
155:
151:
147:
143:
139:
135:
134:logical shift
131:
120:
117:
109:
98:
95:
91:
88:
84:
81:
77:
74:
70:
67: –
66:
62:
61:Find sources:
55:
51:
45:
44:
39:This article
37:
33:
28:
27:
22:
814:. Retrieved
809:
800:
788:. Retrieved
783:
774:
762:. Retrieved
757:
748:
736:. Retrieved
732:the original
727:
718:
706:. Retrieved
702:the original
697:
688:
677:. Retrieved
673:
664:
653:. Retrieved
649:
640:
629:. Retrieved
625:
616:
607:
598:
589:
580:
567:
536:
522:
518:
508:
503:
492:
470:
458:>>>
443:
438:
434:
430:
424:
361:x86 assembly
312:>>>
307:<<<
174:
156:. Unlike an
153:
149:
145:
141:
133:
127:
112:
103:
93:
86:
79:
72:
60:
48:Please help
43:verification
40:
812:. Microsoft
760:. Microsoft
519:unspecified
437:bits on an
238:Standard ML
210:Shift_Right
166:significand
832:Categories
679:2022-11-13
655:2022-01-17
631:2018-01-24
572:References
521:(.NET) or
454:JavaScript
369:Powershell
280:JavaScript
205:Shift_Left
106:April 2016
76:newspapers
523:undefined
446:operators
289:<<
265:>>
260:<<
164:from its
784:llvm.org
608:ss64.com
488:>>
466:<<
462:>>
439:unsigned
427:integers
177:sequence
162:exponent
144:and the
816:9 April
790:9 April
764:9 April
738:9 April
708:9 April
533:Example
496:PowerPC
408:PowerPC
319:Fortran
242:Verilog
90:scholar
482:, and
365:Kotlin
357:Delphi
329:RSHIFT
324:LSHIFT
250:Python
194:Right
92:
85:
78:
71:
63:
336:OCaml
284:Julia
233:Swift
217:Batch
136:is a
97:JSTOR
83:books
818:2016
792:2016
766:2016
740:2016
710:2016
515:LLVM
513:and
471:The
452:and
450:Java
391:MIPS
387:VHDL
276:Java
254:Rust
191:Left
132:, a
69:news
500:x86
480:C++
418:srw
413:slw
401:srl
396:sll
389:),
379:shr
374:shl
346:lsr
341:lsl
246:PHP
225:C++
200:Ada
172:).
152:or
128:In
52:by
834::
808:.
782:.
756:.
726:.
696:.
672:.
648:.
624:.
606:.
588:.
527:C#
484:Go
478:,
367:,
363:,
359:,
355:,
301:F#
282:,
278:,
274:,
252:,
248:,
244:,
240:,
231:,
229:Go
227:,
223:,
219:,
820:.
794:.
768:.
742:.
712:.
682:.
658:.
634:.
610:.
592:.
476:C
435:n
431:n
272:D
221:C
119:)
113:(
108:)
104:(
94:·
87:·
80:·
73:·
46:.
23:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
