/*
	Compatibility <intrin_x86.h> header for GCC -- GCC equivalents of intrinsic
	Microsoft Visual C++ functions. Originally developed for the ReactOS
	(<http://www.reactos.org/>) and TinyKrnl (<http://www.tinykrnl.org/>)
	projects.

	Copyright (c) 2006 KJK::Hyperion <hackbunny@reactos.com>

	Permission is hereby granted, free of charge, to any person obtaining a
	copy of this software and associated documentation files (the "Software"),
	to deal in the Software without restriction, including without limitation
	the rights to use, copy, modify, merge, publish, distribute, sublicense,
	and/or sell copies of the Software, and to permit persons to whom the
	Software is furnished to do so, subject to the following conditions:

	The above copyright notice and this permission notice shall be included in
	all copies or substantial portions of the Software.

	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
	DEALINGS IN THE SOFTWARE.
*/

#pragma once

/*
	NOTE: this is a *compatibility* header. Some functions may look wrong at
	first, but they're only "as wrong" as they would be on Visual C++. Our
	priority is compatibility

	NOTE: unlike most people who write inline asm for GCC, I didn't pull the
	constraints and the uses of __volatile__ out of my... hat. Do not touch
	them. I hate cargo cult programming

	NOTE: review all intrinsics with a return value, add/remove __volatile__
	where necessary. If an intrinsic whose value is ignored generates a no-op
	under Visual C++, __volatile__ must be omitted; if it always generates code
	(for example, if it has side effects), __volatile__ must be specified. GCC
	will only optimize out non-volatile asm blocks with outputs, so input-only
	blocks are safe. Oddities such as the non-volatile 'rdmsr' are intentional
	and follow Visual C++ behavior

	NOTE: GCC and Clang both support __sync_* built-ins for barriers and
	atomic operations.

	Pay attention to the type of barrier. Make it match with what Visual C++
	would use in the same case
*/


/*** Atomic operations ***/

static __inline__ __attribute__((always_inline)) long _InterlockedCompareExchange(volatile long * const Destination, const long Exchange, const long Comperand)
{
	return __sync_val_compare_and_swap(Destination, Comperand, Exchange);
}

static __inline__ __attribute__((always_inline)) long long _InterlockedCompareExchange64(volatile long long * const Destination, const long long Exchange, const long long Comperand)
{
	return __sync_val_compare_and_swap(Destination, Comperand, Exchange);
}

static __inline__ __attribute__((always_inline)) long _InterlockedExchange(volatile long * const Target, const long Value)
{
	/* NOTE: __sync_lock_test_and_set would be an acquire barrier, so we force a full barrier */
	__sync_synchronize();
	return __sync_lock_test_and_set(Target, Value);
}

static __inline__ __attribute__((always_inline)) long _InterlockedExchangeAdd(volatile long * const Addend, const long Value)
{
	return __sync_fetch_and_add(Addend, Value);
}

static __inline__ __attribute__((always_inline)) long _InterlockedDecrement(volatile long * const lpAddend)
{
	return _InterlockedExchangeAdd(lpAddend, -1) - 1;
}

static __inline__ __attribute__((always_inline)) long _InterlockedIncrement(volatile long * const lpAddend)
{
	return _InterlockedExchangeAdd(lpAddend, 1) + 1;
}

/*** System information ***/
static __inline__ __attribute__((always_inline)) void __cpuid(int CPUInfo[], const int InfoType)
{
	__asm__ __volatile__("cpuid" : "=a" (CPUInfo[0]), "=b" (CPUInfo[1]), "=c" (CPUInfo[2]), "=d" (CPUInfo[3]) : "a" (InfoType));
}

static __inline__ __attribute__((always_inline)) unsigned long long __xgetbv(unsigned int index)
{
	unsigned int eax, edx;
	__asm__ __volatile__("xgetbv" : "=a"(eax), "=d"(edx) : "c"(index));
	return ((unsigned long long)edx << 32) | eax;
}

/*** Interrupts ***/
#ifndef __linux__
static __inline__ __attribute__((always_inline)) void __debugbreak(void)
{
	__asm__("int $3");
}
#endif