Re: [patch] spinlocks: remove 'volatile'

trajce nedev
2006-07-08T06:45:19Z

On Sat, 8 Jul 2006, Chase Venters wrote:
>
>Perhaps you should have followed this thread closely before composing your
>assault on Linus. We're not talking about "asm volatile". We're talking
>about
>the "volatile" keyword as applied to variables. 'volatile' as applied to
>inline ASM is of course necessary in many cases -- no one is disputing
>that.
>

Ok, let's port a spinlock macro that spins instead of context switches
instead of using the pthread garbage on IA64 or AMD64:

#if ((defined (_M_IA64) || defined (_M_AMD64)) && !defined(NT_INTEREX))
#include <windows.h>
#pragma intrinsic (_InterlockedExchange)

typedef volatile LONG lock_t[1];

#define LockInit(v) ((v)[0] = 0)
#define LockFree(v) ((v)[0] = 0)
#define Unlock(v) ((v)[0] = 0)

__forceinline void Lock(volatile LONG *hPtr)
{
int iValue;

for (;;) {
iValue = _InterlockedExchange((LPLONG)hPtr, 1);
if (iValue == 0)
return;
while (*hPtr);
}
}

Please show me how I can write this to spinlock without using volatile.

Trajce Nedev
tnedev@mail.ru

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