Re: [MdePkg/BaseLib v1 1/1] MdePkg BaseLib: Add new API CalculateCrc16()

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On Fri, 1 Feb 2019 at 08:11, Ming Huang <ming.huang@linaro.org> wrote:
>
>
>
> On 2/1/2019 2:37 PM, Ni, Ray wrote:
> > There is an CRC16 calculation implementation in
> > SourceLevelDebugPkg/Library/DebugAgent/DebugAgentCommon/DebugAgent.c
> >
> > Does your implementation generate the same CRC16 as above one?
>
> It is not the same with above one.
>

So which polynomial is your CRC-16 implementation based on, and why
does it belong in BaseLib, i.e., what is the relevance for other
BaseLib users for this particular flavour of CRC

Thanks,
Ard.


> >
> >> -----Original Message-----
> >> From: edk2-devel <edk2-devel-bounces@lists.01.org> On Behalf Of Ming
> >> Huang
> >> Sent: Friday, February 1, 2019 2:02 PM
> >> To: linaro-uefi@lists.linaro.org; edk2-devel@lists.01.org; Kinney, Michael D
> >> <michael.d.kinney@intel.com>; Gao, Liming <liming.gao@intel.com>
> >> Cc: huangming23@huawei.com; Dong, Eric <eric.dong@intel.com>;
> >> zhangjinsong2@huawei.com; Zeng, Star <star.zeng@intel.com>;
> >> waip23@126.com; wanghuiqiang@huawei.com; huangdaode@hisilicon.com
> >> Subject: [edk2] [MdePkg/BaseLib v1 1/1] MdePkg BaseLib: Add new API
> >> CalculateCrc16()
> >>
> >> CalculateCrc16() bases on the initialized mCrcTable. When CalculateCrc16() is
> >> used, mCrcTable16 will take 512Bytes size in the image. When
> >> CalculateCrc16() is not used, mCrcTable16 will not be built in the image, and
> >> no size impact.
> >>
> >> Contributed-under: TianoCore Contribution Agreement 1.1
> >> Signed-off-by: Ming Huang <ming.huang@linaro.org>
> >> ---
> >>  MdePkg/Include/Library/BaseLib.h  | 20 ++++++
> >> MdePkg/Library/BaseLib/CheckSum.c | 73 ++++++++++++++++++++
> >>  2 files changed, 93 insertions(+)
> >>
> >> diff --git a/MdePkg/Include/Library/BaseLib.h
> >> b/MdePkg/Include/Library/BaseLib.h
> >> index 1eb842384ee2..956b971e5c69 100644
> >> --- a/MdePkg/Include/Library/BaseLib.h
> >> +++ b/MdePkg/Include/Library/BaseLib.h
> >> @@ -4855,6 +4855,26 @@ CalculateCrc32(
> >>    IN  UINTN                        Length
> >>    );
> >>
> >> +/**
> >> +  Computes and returns a 16-bit CRC for a data buffer.
> >> +  CRC16 value bases on CCITT.
> >> +
> >> +  If Buffer is NULL, then ASSERT().
> >> +  If Length is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT().
> >> +
> >> +  @param[in]  Buffer       A pointer to the buffer on which the 16-bit CRC is to
> >> be computed.
> >> +  @param[in]  Length      The number of bytes in the buffer Data.
> >> +
> >> +  @retval Crc16            The 16-bit CRC was computed for the data buffer.
> >> +
> >> +**/
> >> +UINT16
> >> +EFIAPI
> >> +CalculateCrc16(
> >> +  IN  VOID                         *Buffer,
> >> +  IN  UINTN                        Length
> >> +  );
> >> +
> >>  //
> >>  // Base Library CPU Functions
> >>  //
> >> diff --git a/MdePkg/Library/BaseLib/CheckSum.c
> >> b/MdePkg/Library/BaseLib/CheckSum.c
> >> index 03d49afc5e6c..4e27aebe44bc 100644
> >> --- a/MdePkg/Library/BaseLib/CheckSum.c
> >> +++ b/MdePkg/Library/BaseLib/CheckSum.c
> >> @@ -630,3 +630,76 @@ CalculateCrc32(
> >>
> >>    return Crc ^ 0xffffffff;
> >>  }
> >> +
> >> +GLOBAL_REMOVE_IF_UNREFERENCED CONST UINT16  mCrcTable16[256] =
> >> {
> >> +  0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
> >> +  0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
> >> +  0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
> >> +  0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
> >> +  0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
> >> +  0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
> >> +  0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
> >> +  0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
> >> +  0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
> >> +  0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
> >> +  0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
> >> +  0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
> >> +  0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
> >> +  0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
> >> +  0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
> >> +  0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
> >> +  0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
> >> +  0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
> >> +  0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
> >> +  0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
> >> +  0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
> >> +  0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
> >> +  0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
> >> +  0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
> >> +  0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
> >> +  0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
> >> +  0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
> >> +  0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
> >> +  0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
> >> +  0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
> >> +  0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
> >> +  0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0 };
> >> +
> >> +/**
> >> +  Computes and returns a 16-bit CRC for a data buffer.
> >> +  CRC16 value bases on CCITT.
> >> +
> >> +  If Buffer is NULL, then ASSERT().
> >> +  If Length is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT().
> >> +
> >> +  @param[in]  Buffer       A pointer to the buffer on which the 16-bit CRC is to
> >> be computed.
> >> +  @param[in]  Length      The number of bytes in the buffer Data.
> >> +
> >> +  @retval Crc16            The 16-bit CRC was computed for the data buffer.
> >> +
> >> +**/
> >> +UINT16
> >> +EFIAPI
> >> +CalculateCrc16(
> >> +  IN  VOID                         *Buffer,
> >> +  IN  UINTN                        Length
> >> +  )
> >> +{
> >> +  UINT16  Crc;
> >> +  UINT8   *Ptr;
> >> +
> >> +  ASSERT (Buffer != NULL);
> >> +  ASSERT (Length <= (MAX_ADDRESS - ((UINTN) Buffer) + 1));
> >> +
> >> +  Crc = 0;
> >> +  Ptr = (UINT8 *)Buffer;
> >> +  while (Length) {
> >> +    Crc = mCrcTable16[((UINT8)((Crc >> 8) & 0xff)) ^ *(Ptr++)] ^
> >> +            ((UINT16)(Crc << 8));
> >> +    Length--;
> >> +  }
> >> +
> >> +  return Crc;
> >> +}
> >> +
> >> --
> >> 2.9.5
> >>
> >> _______________________________________________
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