windows-nt/Source/XPSP1/NT/published/sdk/inc/align.h
2020-09-26 16:20:57 +08:00

149 lines
3.7 KiB
C

/*++
Copyright (c) 1988-1992 Microsoft Corporation
Module Name:
Align.h
Abstract:
Author:
John Rogers (JohnRo) 15-May-1991
Environment:
This code assumes that sizeof(DWORD) >= sizeof(LPVOID).
Revision History:
15-May-1991 JohnRo
Created align.h for NT/LAN from OS/2 1.2 HPFS pbmacros.h.
19-Jun-1991 JohnRo
Make sure pointer-to-wider-then-byte doesn't get messed up.
10-Jul-1991 JohnRo
Added ALIGN_BYTE and ALIGN_CHAR for completeness.
21-Aug-1991 CliffV
Fix ROUND_DOWN_* to include ~
03-Dec-1991 JohnRo
Worst-case on MIPS is 8-byte alignment.
Added COUNT_IS_ALIGNED() and POINTER_IS_ALIGNED() macros.
26-Jun-1992 JohnRo
RAID 9933: ALIGN_WORST should be 8 for x86 builds.
--*/
#ifndef _ALIGN_
#define _ALIGN_
// BOOL
// COUNT_IS_ALIGNED(
// IN DWORD Count,
// IN DWORD Pow2 // undefined if this isn't a power of 2.
// );
//
#define COUNT_IS_ALIGNED(Count,Pow2) \
( ( ( (Count) & (((Pow2)-1)) ) == 0) ? TRUE : FALSE )
// BOOL
// POINTER_IS_ALIGNED(
// IN LPVOID Ptr,
// IN DWORD Pow2 // undefined if this isn't a power of 2.
// );
//
#define POINTER_IS_ALIGNED(Ptr,Pow2) \
( ( ( ((ULONG_PTR)(Ptr)) & (((Pow2)-1)) ) == 0) ? TRUE : FALSE )
#define ROUND_DOWN_COUNT(Count,Pow2) \
( (Count) & (~(((LONG)(Pow2))-1)) )
#define ROUND_DOWN_POINTER(Ptr,Pow2) \
( (LPVOID) ROUND_DOWN_COUNT( ((ULONG_PTR)(Ptr)), (Pow2) ) )
// If Count is not already aligned, then
// round Count up to an even multiple of "Pow2". "Pow2" must be a power of 2.
//
// DWORD
// ROUND_UP_COUNT(
// IN DWORD Count,
// IN DWORD Pow2
// );
#define ROUND_UP_COUNT(Count,Pow2) \
( ((Count)+(Pow2)-1) & (~(((LONG)(Pow2))-1)) )
// LPVOID
// ROUND_UP_POINTER(
// IN LPVOID Ptr,
// IN DWORD Pow2
// );
// If Ptr is not already aligned, then round it up until it is.
#define ROUND_UP_POINTER(Ptr,Pow2) \
( (LPVOID) ( (((ULONG_PTR)(Ptr))+(Pow2)-1) & (~(((LONG)(Pow2))-1)) ) )
// Usage: myPtr = ROUND_UP_POINTER( unalignedPtr, ALIGN_LPVOID )
#define ALIGN_BYTE sizeof(UCHAR)
#define ALIGN_CHAR sizeof(CHAR)
#define ALIGN_DESC_CHAR sizeof(DESC_CHAR)
#define ALIGN_DWORD sizeof(DWORD)
#define ALIGN_LONG sizeof(LONG)
#define ALIGN_LPBYTE sizeof(LPBYTE)
#define ALIGN_LPDWORD sizeof(LPDWORD)
#define ALIGN_LPSTR sizeof(LPSTR)
#define ALIGN_LPTSTR sizeof(LPTSTR)
#define ALIGN_LPVOID sizeof(LPVOID)
#define ALIGN_LPWORD sizeof(LPWORD)
#define ALIGN_TCHAR sizeof(TCHAR)
#define ALIGN_WCHAR sizeof(WCHAR)
#define ALIGN_WORD sizeof(WORD)
//
// For now, use a hardcoded constant. however, this should be visited again
// and maybe changed to sizeof(QUAD).
//
#define ALIGN_QUAD 8
#if defined(_X86_)
#define ALIGN_WORST 8
#elif defined(_AMD64_)
#define ALIGN_WORST 8
#elif defined(_ALPHA_)
//
// Worst-case alignment on ALPHA is 8 bytes (for double). Specify this here,
// in case our allocator is used for structures containing this. (That is,
// even though NT/LAN doesn't need this for our data structures, let's be
// permissive.) The alignment requirements apply to Alpha.
//
#define ALIGN_WORST 8
#elif defined(_IA64_)
//
// IA64 note for QUAD: The NT QUAD type definition is NOT the EM 16byte quad type.
// Because of some NT constraints, QUAD type size cannot be changed.
//
#define ALIGN_WORST 16
#else // none of the above
#error "Unknown alignment requirements for align.h"
#endif // none of the above
#endif // _ALIGN_