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Revision 1.76 by root, Mon Jan 20 13:13:56 2020 UTC vs.
Revision 1.78 by root, Mon Jan 20 20:40:06 2020 UTC

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595 595
596=item int ecb_ctz32 (uint32_t x) 596=item int ecb_ctz32 (uint32_t x)
597 597
598=item int ecb_ctz64 (uint64_t x) 598=item int ecb_ctz64 (uint64_t x)
599 599
600=item int ecb_ctz (T x) [C++]
601
600Returns the index of the least significant bit set in C<x> (or 602Returns the index of the least significant bit set in C<x> (or
601equivalently the number of bits set to 0 before the least significant bit 603equivalently the number of bits set to 0 before the least significant bit
602set), starting from 0. If C<x> is 0 the result is undefined. 604set), starting from 0. If C<x> is 0 the result is undefined.
603 605
604For smaller types than C<uint32_t> you can safely use C<ecb_ctz32>. 606For smaller types than C<uint32_t> you can safely use C<ecb_ctz32>.
605 607
608The overloaded C++ C<ecb_ctz> function supports C<uint8_t>, C<uint16_t>,
609C<uint32_t> and C<uint64_t> types.
610
606For example: 611For example:
607 612
608 ecb_ctz32 (3) = 0 613 ecb_ctz32 (3) = 0
609 ecb_ctz32 (6) = 1 614 ecb_ctz32 (6) = 1
610 615
611=item bool ecb_is_pot32 (uint32_t x) 616=item bool ecb_is_pot32 (uint32_t x)
612 617
613=item bool ecb_is_pot64 (uint32_t x) 618=item bool ecb_is_pot64 (uint32_t x)
614 619
620=item bool ecb_is_pot (T x) [C++]
621
615Returns true iff C<x> is a power of two or C<x == 0>. 622Returns true iff C<x> is a power of two or C<x == 0>.
616 623
617For smaller types than C<uint32_t> you can safely use C<ecb_is_pot32>. 624For smaller types than C<uint32_t> you can safely use C<ecb_is_pot32>.
618 625
626The overloaded C++ C<ecb_is_pot> function supports C<uint8_t>, C<uint16_t>,
627C<uint32_t> and C<uint64_t> types.
628
619=item int ecb_ld32 (uint32_t x) 629=item int ecb_ld32 (uint32_t x)
620 630
621=item int ecb_ld64 (uint64_t x) 631=item int ecb_ld64 (uint64_t x)
632
633=item int ecb_ld64 (T x) [C++]
622 634
623Returns the index of the most significant bit set in C<x>, or the number 635Returns the index of the most significant bit set in C<x>, or the number
624of digits the number requires in binary (so that C<< 2**ld <= x < 636of digits the number requires in binary (so that C<< 2**ld <= x <
6252**(ld+1) >>). If C<x> is 0 the result is undefined. A common use case is 6372**(ld+1) >>). If C<x> is 0 the result is undefined. A common use case is
626to compute the integer binary logarithm, i.e. C<floor (log2 (n))>, for 638to compute the integer binary logarithm, i.e. C<floor (log2 (n))>, for
… …
631the given data type), while C<ecb_ld> returns how many bits the number 643the given data type), while C<ecb_ld> returns how many bits the number
632itself requires. 644itself requires.
633 645
634For smaller types than C<uint32_t> you can safely use C<ecb_ld32>. 646For smaller types than C<uint32_t> you can safely use C<ecb_ld32>.
635 647
648The overloaded C++ C<ecb_ld> function supports C<uint8_t>, C<uint16_t>,
649C<uint32_t> and C<uint64_t> types.
650
636=item int ecb_popcount32 (uint32_t x) 651=item int ecb_popcount32 (uint32_t x)
637 652
638=item int ecb_popcount64 (uint64_t x) 653=item int ecb_popcount64 (uint64_t x)
639 654
655=item int ecb_popcount (T x) [C++]
656
640Returns the number of bits set to 1 in C<x>. 657Returns the number of bits set to 1 in C<x>.
641 658
642For smaller types than C<uint32_t> you can safely use C<ecb_popcount32>. 659For smaller types than C<uint32_t> you can safely use C<ecb_popcount32>.
660
661The overloaded C++ C<ecb_popcount> function supports C<uint8_t>, C<uint16_t>,
662C<uint32_t> and C<uint64_t> types.
643 663
644For example: 664For example:
645 665
646 ecb_popcount32 (7) = 3 666 ecb_popcount32 (7) = 3
647 ecb_popcount32 (255) = 8 667 ecb_popcount32 (255) = 8
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650 670
651=item uint16_t ecb_bitrev16 (uint16_t x) 671=item uint16_t ecb_bitrev16 (uint16_t x)
652 672
653=item uint32_t ecb_bitrev32 (uint32_t x) 673=item uint32_t ecb_bitrev32 (uint32_t x)
654 674
675=item T ecb_bitrev (T x) [C++]
676
655Reverses the bits in x, i.e. the MSB becomes the LSB, MSB-1 becomes LSB+1 677Reverses the bits in x, i.e. the MSB becomes the LSB, MSB-1 becomes LSB+1
656and so on. 678and so on.
657 679
680The overloaded C++ C<ecb_bitrev> function supports C<uint8_t>, C<uint16_t> and C<uint32_t> types.
681
658Example: 682Example:
659 683
660 ecb_bitrev8 (0xa7) = 0xea 684 ecb_bitrev8 (0xa7) = 0xea
661 ecb_bitrev32 (0xffcc4411) = 0x882233ff 685 ecb_bitrev32 (0xffcc4411) = 0x882233ff
662 686
687=item T ecb_bitrev (T x) [C++]
688
689Overloaded C++ bitrev function.
690
691C<T> must be one of C<uint8_t>, C<uint16_t> or C<uint32_t>.
692
663=item uint32_t ecb_bswap16 (uint32_t x) 693=item uint32_t ecb_bswap16 (uint32_t x)
664 694
665=item uint32_t ecb_bswap32 (uint32_t x) 695=item uint32_t ecb_bswap32 (uint32_t x)
666 696
667=item uint64_t ecb_bswap64 (uint64_t x) 697=item uint64_t ecb_bswap64 (uint64_t x)
698
699=item T ecb_bswap (T x)
668 700
669These functions return the value of the 16-bit (32-bit, 64-bit) value 701These functions return the value of the 16-bit (32-bit, 64-bit) value
670C<x> after reversing the order of bytes (0x11223344 becomes 0x44332211 in 702C<x> after reversing the order of bytes (0x11223344 becomes 0x44332211 in
671C<ecb_bswap32>). 703C<ecb_bswap32>).
672 704
673=item T ecb_bswap (T x) [C++] 705The overloaded C++ C<ecb_bswap> function supports C<uint8_t>, C<uint16_t>,
674 706C<uint32_t> and C<uint64_t> types.
675For C++, an additional generic bswap function is provided. It supports
676C<uint8_t>, C<uint16_t>, C<uint32_t> and C<uint64_t>.
677 707
678=item uint8_t ecb_rotl8 (uint8_t x, unsigned int count) 708=item uint8_t ecb_rotl8 (uint8_t x, unsigned int count)
679 709
680=item uint16_t ecb_rotl16 (uint16_t x, unsigned int count) 710=item uint16_t ecb_rotl16 (uint16_t x, unsigned int count)
681 711
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697 727
698Current GCC versions understand these functions and usually compile them 728Current GCC versions understand these functions and usually compile them
699to "optimal" code (e.g. a single C<rol> or a combination of C<shld> on 729to "optimal" code (e.g. a single C<rol> or a combination of C<shld> on
700x86). 730x86).
701 731
732=item T ecb_rotl (T x, unsigned int count) [C++]
733
734=item T ecb_rotr (T x, unsigned int count) [C++]
735
736Overloaded C++ rotl/rotr functions.
737
738C<T> must be one of C<uint8_t>, C<uint16_t>, C<uint32_t> or C<uint64_t>.
739
702=back 740=back
703 741
704=head2 HOST ENDIANNESS CONVERSION 742=head2 HOST ENDIANNESS CONVERSION
705 743
706=over 4 744=over 4
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737Like above, but converts I<from> host byte order to the specified 775Like above, but converts I<from> host byte order to the specified
738endianness. 776endianness.
739 777
740=back 778=back
741 779
742In C++ the following additional functions are supported: 780In C++ the following additional template functions are supported:
743 781
744=over 4 782=over 4
745 783
746=item T ecb_be_to_host (T v) 784=item T ecb_be_to_host (T v)
747 785
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749 787
750=item T ecb_host_to_be (T v) 788=item T ecb_host_to_be (T v)
751 789
752=item T ecb_host_to_le (T v) 790=item T ecb_host_to_le (T v)
753 791
754These work like their C counterparts, above, but use templates for the 792These functions work like their C counterparts, above, but use templates,
755type, which make them useful in generic code. 793which make them useful in generic code.
756 794
757C<T> must be one of C<uint8_t>, C<uint16_t>, C<uint32_t> or C<uint64_t> 795C<T> must be one of C<uint8_t>, C<uint16_t>, C<uint32_t> or C<uint64_t>
758(so unlike their C counterparts, there is a version for C<uint8_t>, which 796(so unlike their C counterparts, there is a version for C<uint8_t>, which
759again can be useful in generic code). 797again can be useful in generic code).
760 798
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812Like above, but additionally convert from host byte order to big endian 850Like above, but additionally convert from host byte order to big endian
813(C<be>) or little endian (C<le>) byte order while doing so. 851(C<be>) or little endian (C<le>) byte order while doing so.
814 852
815=back 853=back
816 854
817In C++ the following additional functions are supported: 855In C++ the following additional template functions are supported:
818 856
819=over 4 857=over 4
820 858
821=item T ecb_peek (const void *ptr) 859=item T ecb_peek (const void *ptr)
822 860

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