/*
 * Copyright (c) 2005 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup amd64	
 * @{
 */
/** @file
 */

#ifndef KERN_amd64_ASM_H_
#define KERN_amd64_ASM_H_

#include <config.h>

extern void asm_delay_loop(uint32_t t);
extern void asm_fake_loop(uint32_t t);

/** Return base address of current stack.
 *
 * Return the base address of the current stack.
 * The stack is assumed to be STACK_SIZE bytes long.
 * The stack must start on page boundary.
 */
static inline uintptr_t get_stack_base(void)
{
	uintptr_t v;
	
	asm volatile ("andq %%rsp, %0\n" : "=r" (v) : "0" (~((uint64_t)STACK_SIZE-1)));
	
	return v;
}

static inline void cpu_sleep(void)
{
	asm volatile ("hlt\n");
}

static inline void cpu_halt(void)
{
	asm volatile ("hlt\n");
}


/** Byte from port
 *
 * Get byte from port
 *
 * @param port Port to read from
 * @return Value read
 */
static inline uint8_t inb(uint16_t port)
{
	uint8_t val;

	asm volatile ("inb %w1, %b0 \n" : "=a" (val) : "d" (port));
	return val;
}

/** Byte to port
 *
 * Output byte to port
 *
 * @param port Port to write to
 * @param val Value to write
 */
static inline void outb(uint16_t port, uint8_t val)
{
	asm volatile ("outb %b0, %w1\n" : : "a" (val), "d" (port));
}

/** Swap Hidden part of GS register with visible one */
static inline void swapgs(void)
{
	asm volatile("swapgs");
}

/** Enable interrupts.
 *
 * Enable interrupts and return previous
 * value of EFLAGS.
 *
 * @return Old interrupt priority level.
 */
static inline ipl_t interrupts_enable(void) {
	ipl_t v;
	__asm__ volatile (
		"pushfq\n"
		"popq %0\n"
		"sti\n"
		: "=r" (v)
	);
	return v;
}

/** Disable interrupts.
 *
 * Disable interrupts and return previous
 * value of EFLAGS.
 *
 * @return Old interrupt priority level.
 */
static inline ipl_t interrupts_disable(void) {
	ipl_t v;
	__asm__ volatile (
		"pushfq\n"
		"popq %0\n"
		"cli\n"
		: "=r" (v)
		);
	return v;
}

/** Restore interrupt priority level.
 *
 * Restore EFLAGS.
 *
 * @param ipl Saved interrupt priority level.
 */
static inline void interrupts_restore(ipl_t ipl) {
	__asm__ volatile (
		"pushq %0\n"
		"popfq\n"
		: : "r" (ipl)
		);
}

/** Return interrupt priority level.
 *
 * Return EFLAFS.
 *
 * @return Current interrupt priority level.
 */
static inline ipl_t interrupts_read(void) {
	ipl_t v;
	__asm__ volatile (
		"pushfq\n"
		"popq %0\n"
		: "=r" (v)
	);
	return v;
}

/** Write to MSR */
static inline void write_msr(uint32_t msr, uint64_t value)
{
	__asm__ volatile (
		"wrmsr;" : : "c" (msr), 
		"a" ((uint32_t)(value)),
		"d" ((uint32_t)(value >> 32))
		);
}

static inline unative_t read_msr(uint32_t msr)
{
	uint32_t ax, dx;

	__asm__ volatile (
		"rdmsr;" : "=a"(ax), "=d"(dx) : "c" (msr)
		);
	return ((uint64_t)dx << 32) | ax;
}


/** Enable local APIC
 *
 * Enable local APIC in MSR.
 */
static inline void enable_l_apic_in_msr()
{
	__asm__ volatile (
		"movl $0x1b, %%ecx\n"
		"rdmsr\n"
		"orl $(1<<11),%%eax\n"
		"orl $(0xfee00000),%%eax\n"
		"wrmsr\n"
		:
		:
		:"%eax","%ecx","%edx"
		);
}

static inline uintptr_t * get_ip() 
{
	uintptr_t *ip;

	__asm__ volatile (
		"mov %%rip, %0"
		: "=r" (ip)
		);
	return ip;
}

/** Invalidate TLB Entry.
 *
 * @param addr Address on a page whose TLB entry is to be invalidated.
 */
static inline void invlpg(uintptr_t addr)
{
	__asm__ volatile ("invlpg %0\n" :: "m" (*((unative_t *)addr)));
}

/** Load GDTR register from memory.
 *
 * @param gdtr_reg Address of memory from where to load GDTR.
 */
static inline void gdtr_load(struct ptr_16_64 *gdtr_reg)
{
	__asm__ volatile ("lgdtq %0\n" : : "m" (*gdtr_reg));
}

/** Store GDTR register to memory.
 *
 * @param gdtr_reg Address of memory to where to load GDTR.
 */
static inline void gdtr_store(struct ptr_16_64 *gdtr_reg)
{
	__asm__ volatile ("sgdtq %0\n" : : "m" (*gdtr_reg));
}

/** Load IDTR register from memory.
 *
 * @param idtr_reg Address of memory from where to load IDTR.
 */
static inline void idtr_load(struct ptr_16_64 *idtr_reg)
{
	__asm__ volatile ("lidtq %0\n" : : "m" (*idtr_reg));
}

/** Load TR from descriptor table.
 *
 * @param sel Selector specifying descriptor of TSS segment.
 */
static inline void tr_load(uint16_t sel)
{
	__asm__ volatile ("ltr %0" : : "r" (sel));
}

#define GEN_READ_REG(reg) static inline unative_t read_ ##reg (void) \
    { \
	unative_t res; \
	__asm__ volatile ("movq %%" #reg ", %0" : "=r" (res) ); \
	return res; \
    }

#define GEN_WRITE_REG(reg) static inline void write_ ##reg (unative_t regn) \
    { \
	__asm__ volatile ("movq %0, %%" #reg : : "r" (regn)); \
    }

GEN_READ_REG(cr0)
GEN_READ_REG(cr2)
GEN_READ_REG(cr3)
GEN_WRITE_REG(cr3)

GEN_READ_REG(dr0)
GEN_READ_REG(dr1)
GEN_READ_REG(dr2)
GEN_READ_REG(dr3)
GEN_READ_REG(dr6)
GEN_READ_REG(dr7)

GEN_WRITE_REG(dr0)
GEN_WRITE_REG(dr1)
GEN_WRITE_REG(dr2)
GEN_WRITE_REG(dr3)
GEN_WRITE_REG(dr6)
GEN_WRITE_REG(dr7)

extern size_t interrupt_handler_size;
extern void interrupt_handlers(void);

#endif

/** @}
 */