/* Copyright (C) 2011 DJ Delorie, see COPYING.DJ for details */ /* Copyright (C) 2003 DJ Delorie, see COPYING.DJ for details */ /* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */ /* Copyright (c) 1995 DJ Delorie. Permission granted to use for any purpose, provided this copyright remains attached and unmodified. THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ» º Far Pointer Simulation Functions º ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ This file attempts to make up for the lack of a "far" keyword in GCC. Although it doesn't provide access to far call APIs (like Windows), it does allow you to do far pointer data access without the overhead of movedata() or dosmemget/dosmemput(). You should *always* include this file when using these functions and compile with optimization enabled. They don't exist as normal functions in any library, and they compile down to only a few opcodes when used this way. They are almost as fast as native pointer operations, and about as fast as far pointers can get. If you don't use optimization, this file becomes prototypes for farptr.c, which generates real functions for these when not optimizing. When optimizing, farptr.c compiles to nothing. There are two types of functions here - standalone and invariant. The standalone functions take a selector and offset. These are used when you need only a few accesses, time isn't critical, or you don't know what's in the %fs register. The invariant ones don't take a selector, they only take an offset. These are used inside loops and in time-critical accesses where the selector doesn't change. To specify the selector, use the farsetsel() function. That selector is used for all farns*() functions until changed. You can use _fargetsel() if you want to temporary change the selector with _farsetsel() and restore it afterwards. The farpoke* and farpeek* take selectors. The farnspoke* and farnspeek* don't (note the `ns' for `no selector'). Warning: These routines all use the %fs register for their accesses. GCC normally uses only %ds and %es, and libc functions (movedata, dosmemget, dosmemput) use %gs. Still, you should be careful about assumptions concerning whether or not the value you put in %fs will be preserved across calls to other functions. If you guess wrong, your program will crash. Better safe than sorry. */ #ifndef __dj_include_sys_farptr_h_ #define __dj_include_sys_farptr_h_ #ifdef __cplusplus extern "C" { #endif #ifndef __dj_ENFORCE_ANSI_FREESTANDING #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) \ || !defined(__STRICT_ANSI__) || defined(__cplusplus) #endif /* (__STDC_VERSION__ >= 199901L) || !__STRICT_ANSI__ */ #ifndef __STRICT_ANSI__ #ifndef _POSIX_SOURCE #include void _farpokeb(unsigned short, ULONG32, unsigned char); void _farpokew(unsigned short, ULONG32, unsigned short); void _farpokel(unsigned short, ULONG32, ULONG32); unsigned char _farpeekb(unsigned short, ULONG32); unsigned short _farpeekw(unsigned short, ULONG32); ULONG32 _farpeekl(unsigned short, ULONG32); void _farsetsel(unsigned short); unsigned short _fargetsel(void); void _farnspokeb(ULONG32, unsigned char); void _farnspokew(ULONG32, unsigned short); void _farnspokel(ULONG32, ULONG32); unsigned char _farnspeekb(ULONG32); unsigned short _farnspeekw(ULONG32); ULONG32 _farnspeekl(ULONG32); #endif /* !_POSIX_SOURCE */ #endif /* !__STRICT_ANSI__ */ #endif /* !__dj_ENFORCE_ANSI_FREESTANDING */ #ifndef __dj_ENFORCE_FUNCTION_CALLS #endif /* !__dj_ENFORCE_FUNCTION_CALLS */ #ifdef __cplusplus } #endif #endif /* !__dj_include_sys_farptr_h_ */