Hi!
11-Июн-2006 19:56 [EMAIL PROTECTED] (Blair Campbell) wrote to
[email protected]:
BC> simple macros can be defined to access low and high bits of CPU
BC> registers. If you feel like making some for me, feel free :-) .
>> >> BC> + displayString(TEXT_MSG_VER_DOS_VERSION, regs.r_ax & 0xFF,
>> >> regs.r_ax >> 8);
>> >> intr() is bad, because REGPACK doesn't allows to access registers
>> >> parts
>> >> (for example, AL/AH), and this causes noticeably inefficient and
unreadable
>> >> code. Why not use int86(), which you already used in other places?
First, macros you may get from portab.h in (newer) kernels:
______________O\_/_________________________________\_/O______________
#define lonibble(v) (0x0f & (v))
#define hinibble(v) (0xf0 & (v))
#if CHAR_BIT == 8
# define lobyte(v) ((UBYTE)(v))
#else
# define lobyte(v) ((UBYTE)(0xff & (v)))
#endif
#define hibyte(v) lobyte ((UWORD)(v) >> 8u)
#if USHRT_MAX == 0xFFFF
# define loword(v) ((unsigned short)(v))
#else
# define loword(v) (0xFFFF & (unsigned)(v))
#endif
#define hiword(v) loword ((v) >> 16u)
#define MK_UWORD(hib,lob) (((UWORD)(hib) << 8u) | (UBYTE)(lob))
#define MK_ULONG(hiw,low) (((ULONG)(hiw) << 16u) | (UWORD)(low))
[...]
#define MK_PTR(type,seg,ofs) ((type FAR*) MK_FP (seg, ofs))
_____________________________________________________________________
O/~\ /~\O
Second, macros here can't fix inherent ineffectiveness (and lesser
readability) of REGPACK/intr() usage. Even with these macros
displayString (TEXT_MSG_VER_DOS_VERSION, lobyte (regs.r_ax),
hibyte (regs.r_ax));
is less readable (and often less effective), than
displayString (TEXT_MSG_VER_DOS_VERSION, regs.r.h.al, regs.r.h.ah);
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