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Diffstat (limited to 'EDK/Foundation/Library/EfiCommonLib/Math.c')
-rw-r--r-- | EDK/Foundation/Library/EfiCommonLib/Math.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/EDK/Foundation/Library/EfiCommonLib/Math.c b/EDK/Foundation/Library/EfiCommonLib/Math.c new file mode 100644 index 0000000..8767fa6 --- /dev/null +++ b/EDK/Foundation/Library/EfiCommonLib/Math.c @@ -0,0 +1,216 @@ +/*++ + +Copyright (c) 2004, Intel Corporation +All rights reserved. This program and the accompanying materials +are licensed and made available under the terms and conditions of the BSD License +which accompanies this distribution. The full text of the license may be found at +http://opensource.org/licenses/bsd-license.php + +THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, +WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. + +Module Name: + + Math.c + +Abstract: + + Math worker functions. + +--*/ + +#include "Tiano.h" + +UINT64 +LShiftU64 ( + IN UINT64 Operand, + IN UINTN Count + ) +/*++ + +Routine Description: + + This routine allows a 64 bit value to be left shifted by 32 bits and + returns the shifted value. + Count is valid up 63. (Only Bits 0-5 is valid for Count) + +Arguments: + + Operand - Value to be shifted + Count - Number of times to shift left. + +Returns: + + Value shifted left identified by the Count. + +--*/ +{ + return Operand << Count; +} + +UINT64 +MultU64x32 ( + IN UINT64 Multiplicand, + IN UINTN Multiplier + ) +/*++ + +Routine Description: + + This routine allows a 64 bit value to be multiplied with a 32 bit + value returns 64bit result. + No checking if the result is greater than 64bits + +Arguments: + + Multiplicand - multiplicand + Multiplier - multiplier + +Returns: + + Multiplicand * Multiplier + +--*/ +{ + return Multiplicand * Multiplier; +} + +UINT64 +RShiftU64 ( + IN UINT64 Operand, + IN UINTN Count + ) +/*++ + +Routine Description: + + This routine allows a 64 bit value to be right shifted by 32 bits and returns the + shifted value. + Count is valid up 63. (Only Bits 0-5 is valid for Count) + +Arguments: + + Operand - Value to be shifted + Count - Number of times to shift right. + +Returns: + + Value shifted right identified by the Count. + +--*/ +{ + return Operand >> Count; +} + +UINT64 +DivU64x32 ( + IN UINT64 Dividend, + IN UINTN Divisor, + OUT UINTN *Remainder OPTIONAL + ) +/*++ + +Routine Description: + + This routine allows a 64 bit value to be divided with a 32 bit value returns + 64bit result and the Remainder. + +Arguments: + + Dividend - dividend + Divisor - divisor + Remainder - buffer for remainder + +Returns: + + Dividend / Divisor + Remainder = Dividend mod Divisor + +--*/ +{ + if (Remainder != NULL) { + *Remainder = Dividend % Divisor; + } + + return Dividend / Divisor; +} + +UINT8 +Log2 ( + IN UINT64 Operand + ) +/*++ + +Routine Description: + + This function computes rounded down log2 of the Operand. This is an equivalent + of the position of the highest bit set in the Operand treated as a mask. + E.g., Log2 (0x0001) == 0, Log2 (0x0002) == 1, Log2 (0x0003) == 1, Log2 (0x0005) == 2 + Log2 (0x4000) == 14, Log2 (0x8000) == 15, Log2 (0xC000) == 15, Log2 (0xFFFF) == 15, etc. + +Arguments: + Operand - value of which the Log2 is to be computed. + +Returns: + Rounded down log2 of the Operand or 0xFF if zero passed in. + +--*/ +{ + UINT8 Bitpos; + Bitpos = 0; + + if (Operand == 0) { + return (0xff); + } + + while (Operand != 0) { + Operand >>= 1; + Bitpos++; + } + return (Bitpos - 1); + +} + +UINT64 +GetPowerOfTwo ( + IN UINT64 Operand + ) +/*++ + +Routine Description: + + Calculates the largest integer that is both + a power of two and less than Input + +Arguments: + + Operand - value to calculate power of two + +Returns: + + the largest integer that is both a power of + two and less than Input + +--*/ +{ + UINT8 Bitpos; + Bitpos = 0; + + if (Operand == 0) { + return 0; + } + + while (Operand != 0) { + Operand >>= 1; + Bitpos++; + } + + Operand = 1; + Bitpos--; + while (Bitpos != 0) { + Operand <<= 1; + Bitpos--; + } + + return Operand; +} |