b331b99fae
The runtime test whether the compiler supports arithmetic shift of negative signed numbers currently relies on undefined behavior in C, which means that all bets are off regarding whether the condition that follows passes or fails, regardless of whether the compiler in fact supports arithmetic shift or not. Relevant quote from ISO C99 (6.5.7/4) The result of E1 << E2 is E1 left-shifted E2 bit positions; vacated bits are filled with zeros. If E1 has an unsigned type, the value of the result is E1 × 2^E2, reduced modulo one more than the maximum value representable in the result type. If E1 has a signed type and nonnegative value, and E1 × 2^E2 is representable in the result type, then that is the resulting value; otherwise, the behavior is undefined. For historic purposes, let's keep the test in place (although it is doubtful we actually need it) but rewrite it in a way that prevents compilers from this century from doing whacky things with it. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Liming Gao <liming.gao@intel.com> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19580 6f19259b-4bc3-4df7-8a09-765794883524
369 lines
10 KiB
C
369 lines
10 KiB
C
/** @file
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Leaf math worker functions that require 64-bit arithmetic support from the
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compiler.
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Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
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This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php.
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include "BaseLibInternals.h"
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/**
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Shifts a 64-bit integer left between 0 and 63 bits. The low bits
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are filled with zeros. The shifted value is returned.
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This function shifts the 64-bit value Operand to the left by Count bits. The
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low Count bits are set to zero. The shifted value is returned.
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@param Operand The 64-bit operand to shift left.
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@param Count The number of bits to shift left.
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@return Operand << Count.
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**/
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UINT64
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EFIAPI
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InternalMathLShiftU64 (
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IN UINT64 Operand,
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IN UINTN Count
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)
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{
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return Operand << Count;
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}
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/**
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Shifts a 64-bit integer right between 0 and 63 bits. This high bits
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are filled with zeros. The shifted value is returned.
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This function shifts the 64-bit value Operand to the right by Count bits. The
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high Count bits are set to zero. The shifted value is returned.
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@param Operand The 64-bit operand to shift right.
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@param Count The number of bits to shift right.
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@return Operand >> Count.
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**/
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UINT64
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EFIAPI
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InternalMathRShiftU64 (
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IN UINT64 Operand,
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IN UINTN Count
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)
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{
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return Operand >> Count;
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}
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/**
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Shifts a 64-bit integer right between 0 and 63 bits. The high bits
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are filled with original integer's bit 63. The shifted value is returned.
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This function shifts the 64-bit value Operand to the right by Count bits. The
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high Count bits are set to bit 63 of Operand. The shifted value is returned.
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@param Operand The 64-bit operand to shift right.
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@param Count The number of bits to shift right.
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@return Operand arithmetically shifted right by Count.
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**/
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UINT64
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EFIAPI
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InternalMathARShiftU64 (
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IN UINT64 Operand,
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IN UINTN Count
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)
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{
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INTN TestValue;
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//
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// Test if this compiler supports arithmetic shift
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//
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TestValue = (INTN)((INT64)(1ULL << 63) >> 63);
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if (TestValue == -1) {
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//
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// Arithmetic shift is supported
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//
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return (UINT64)((INT64)Operand >> Count);
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}
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//
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// Arithmetic is not supported
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//
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return (Operand >> Count) |
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((INTN)Operand < 0 ? ~((UINTN)-1 >> Count) : 0);
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}
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/**
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Rotates a 64-bit integer left between 0 and 63 bits, filling
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the low bits with the high bits that were rotated.
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This function rotates the 64-bit value Operand to the left by Count bits. The
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low Count bits are fill with the high Count bits of Operand. The rotated
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value is returned.
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@param Operand The 64-bit operand to rotate left.
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@param Count The number of bits to rotate left.
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@return Operand <<< Count.
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**/
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UINT64
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EFIAPI
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InternalMathLRotU64 (
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IN UINT64 Operand,
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IN UINTN Count
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)
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{
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return (Operand << Count) | (Operand >> (64 - Count));
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}
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/**
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Rotates a 64-bit integer right between 0 and 63 bits, filling
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the high bits with the high low bits that were rotated.
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This function rotates the 64-bit value Operand to the right by Count bits.
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The high Count bits are fill with the low Count bits of Operand. The rotated
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value is returned.
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@param Operand The 64-bit operand to rotate right.
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@param Count The number of bits to rotate right.
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@return Operand >>> Count.
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**/
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UINT64
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EFIAPI
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InternalMathRRotU64 (
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IN UINT64 Operand,
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IN UINTN Count
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)
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{
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return (Operand >> Count) | (Operand << (64 - Count));
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}
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/**
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Switches the endianess of a 64-bit integer.
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This function swaps the bytes in a 64-bit unsigned value to switch the value
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from little endian to big endian or vice versa. The byte swapped value is
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returned.
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@param Operand A 64-bit unsigned value.
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@return The byte swapped Operand.
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**/
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UINT64
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EFIAPI
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InternalMathSwapBytes64 (
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IN UINT64 Operand
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)
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{
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UINT64 LowerBytes;
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UINT64 HigherBytes;
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LowerBytes = (UINT64) SwapBytes32 ((UINT32) Operand);
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HigherBytes = (UINT64) SwapBytes32 ((UINT32) (Operand >> 32));
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return (LowerBytes << 32 | HigherBytes);
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}
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/**
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Multiplies a 64-bit unsigned integer by a 32-bit unsigned integer
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and generates a 64-bit unsigned result.
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This function multiplies the 64-bit unsigned value Multiplicand by the 32-bit
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unsigned value Multiplier and generates a 64-bit unsigned result. This 64-
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bit unsigned result is returned.
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@param Multiplicand A 64-bit unsigned value.
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@param Multiplier A 32-bit unsigned value.
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@return Multiplicand * Multiplier
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**/
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UINT64
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EFIAPI
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InternalMathMultU64x32 (
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IN UINT64 Multiplicand,
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IN UINT32 Multiplier
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)
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{
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return Multiplicand * Multiplier;
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}
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/**
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Multiplies a 64-bit unsigned integer by a 64-bit unsigned integer
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and generates a 64-bit unsigned result.
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This function multiplies the 64-bit unsigned value Multiplicand by the 64-bit
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unsigned value Multiplier and generates a 64-bit unsigned result. This 64-
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bit unsigned result is returned.
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@param Multiplicand A 64-bit unsigned value.
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@param Multiplier A 64-bit unsigned value.
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@return Multiplicand * Multiplier.
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**/
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UINT64
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EFIAPI
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InternalMathMultU64x64 (
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IN UINT64 Multiplicand,
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IN UINT64 Multiplier
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)
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{
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return Multiplicand * Multiplier;
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}
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/**
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Divides a 64-bit unsigned integer by a 32-bit unsigned integer and
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generates a 64-bit unsigned result.
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This function divides the 64-bit unsigned value Dividend by the 32-bit
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unsigned value Divisor and generates a 64-bit unsigned quotient. This
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function returns the 64-bit unsigned quotient.
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@param Dividend A 64-bit unsigned value.
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@param Divisor A 32-bit unsigned value.
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@return Dividend / Divisor.
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**/
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UINT64
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EFIAPI
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InternalMathDivU64x32 (
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IN UINT64 Dividend,
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IN UINT32 Divisor
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)
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{
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return Dividend / Divisor;
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}
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/**
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Divides a 64-bit unsigned integer by a 32-bit unsigned integer and
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generates a 32-bit unsigned remainder.
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This function divides the 64-bit unsigned value Dividend by the 32-bit
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unsigned value Divisor and generates a 32-bit remainder. This function
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returns the 32-bit unsigned remainder.
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@param Dividend A 64-bit unsigned value.
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@param Divisor A 32-bit unsigned value.
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@return Dividend % Divisor.
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**/
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UINT32
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EFIAPI
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InternalMathModU64x32 (
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IN UINT64 Dividend,
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IN UINT32 Divisor
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)
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{
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return (UINT32)(Dividend % Divisor);
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}
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/**
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Divides a 64-bit unsigned integer by a 32-bit unsigned integer and
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generates a 64-bit unsigned result and an optional 32-bit unsigned remainder.
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This function divides the 64-bit unsigned value Dividend by the 32-bit
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unsigned value Divisor and generates a 64-bit unsigned quotient. If Remainder
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is not NULL, then the 32-bit unsigned remainder is returned in Remainder.
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This function returns the 64-bit unsigned quotient.
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@param Dividend A 64-bit unsigned value.
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@param Divisor A 32-bit unsigned value.
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@param Remainder A pointer to a 32-bit unsigned value. This parameter is
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optional and may be NULL.
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@return Dividend / Divisor.
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**/
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UINT64
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EFIAPI
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InternalMathDivRemU64x32 (
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IN UINT64 Dividend,
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IN UINT32 Divisor,
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OUT UINT32 *Remainder OPTIONAL
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)
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{
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if (Remainder != NULL) {
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*Remainder = (UINT32)(Dividend % Divisor);
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}
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return Dividend / Divisor;
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}
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/**
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Divides a 64-bit unsigned integer by a 64-bit unsigned integer and
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generates a 64-bit unsigned result and an optional 64-bit unsigned remainder.
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This function divides the 64-bit unsigned value Dividend by the 64-bit
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unsigned value Divisor and generates a 64-bit unsigned quotient. If Remainder
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is not NULL, then the 64-bit unsigned remainder is returned in Remainder.
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This function returns the 64-bit unsigned quotient.
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@param Dividend A 64-bit unsigned value.
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@param Divisor A 64-bit unsigned value.
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@param Remainder A pointer to a 64-bit unsigned value. This parameter is
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optional and may be NULL.
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@return Dividend / Divisor
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**/
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UINT64
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EFIAPI
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InternalMathDivRemU64x64 (
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IN UINT64 Dividend,
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IN UINT64 Divisor,
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OUT UINT64 *Remainder OPTIONAL
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)
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{
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if (Remainder != NULL) {
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*Remainder = Dividend % Divisor;
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}
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return Dividend / Divisor;
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}
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/**
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Divides a 64-bit signed integer by a 64-bit signed integer and
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generates a 64-bit signed result and an optional 64-bit signed remainder.
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This function divides the 64-bit signed value Dividend by the 64-bit
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signed value Divisor and generates a 64-bit signed quotient. If Remainder
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is not NULL, then the 64-bit signed remainder is returned in Remainder.
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This function returns the 64-bit signed quotient.
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@param Dividend A 64-bit signed value.
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@param Divisor A 64-bit signed value.
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@param Remainder A pointer to a 64-bit signed value. This parameter is
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optional and may be NULL.
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@return Dividend / Divisor.
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**/
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INT64
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EFIAPI
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InternalMathDivRemS64x64 (
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IN INT64 Dividend,
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IN INT64 Divisor,
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OUT INT64 *Remainder OPTIONAL
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)
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{
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if (Remainder != NULL) {
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*Remainder = Dividend % Divisor;
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}
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return Dividend / Divisor;
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}
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