//----------------------------------------------------------------------------//
//                           GNU GPL OS/K                                     //
//                                                                            //
//  Desc:       Inline assembly functions                                     //
//                                                                            //
//                                                                            //
//  Copyright © 2018-2019 The OS/K Team                                       //
//                                                                            //
//  This file is part of OS/K.                                                //
//                                                                            //
//  OS/K is free software: you can redistribute it and/or modify              //
//  it under the terms of the GNU General Public License as published by      //
//  the Free Software Foundation, either version 3 of the License, or         //
//  any later version.                                                        //
//                                                                            //
//  OS/K is distributed in the hope that it will be useful,                   //
//  but WITHOUT ANY WARRANTY//without even the implied warranty of            //
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             //
//  GNU General Public License for more details.                              //
//                                                                            //
//  You should have received a copy of the GNU General Public License         //
//  along with OS/K.  If not, see <https://www.gnu.org/licenses/>.            //
//----------------------------------------------------------------------------//

#ifndef _LIBC_H
#include <libc.h>
#endif

#ifndef _ASM_H
#define _ASM_H

//------------------------------------------//
//           IRQ-related stuff              //
//------------------------------------------//

//
// Returns whether IRQs are enabled
//
static inline bool KeCheckIRQStatus(void) {
    ulong flags;
    asm volatile ("pushf\n\tpop %0" : "=g"(flags) );
    return flags & (1 << 9);
}

//
// Disables IRQs
//
#define KeDisableIRQs() asm volatile ("cli")

//
// Enables IRQs
//
#define KeEnableIRQs() asm volatile ("sti")

//
// Disables IRQs, but saves its previous state
//
static inline ulong KePauseIRQs(void) {
    ulong flags;
    asm volatile ("pushf\n\tcli\n\tpop %0" : "=r"(flags) : : "memory");
    return flags;
}

extern void IoSendEOItoPIC(uchar isr);
extern void IoEnableNMI(void);
extern void IoDisableNMI(void);

//
// Restore IRQ flag to its state before KePauseIRQs
//
#define KeRestoreIRQs(flags) asm("push %0\n\tpopf" : : "rm"(flags) : "memory","cc")

//------------------------------------------//
//       101 ways to hang the system        //
//------------------------------------------//

//
// Just relaxes the CPU a few cycles
//
#define KeRelaxCPU() asm volatile("pause\n": : : "memory")

//
// Pauses CPU until next interuption
//
#define KePauseCPU() asm volatile ("sti\n\thlt")

//
// Halts the CPU indefinitely
//
#define KeHaltCPU() do { asm volatile ("hlt"); } while (1)

//
// Halts the system, making sure it won't recover
//
#define KeCrashSystem() do { KeDisableIRQs(); KeHaltCPU(); } while (1)

//------------------------------------------//
//                Ports I/O                 //
//------------------------------------------//

static inline void IoWriteByteOnPort(ushort port, uchar val)
{ asm volatile ("outb %1, %0" : : "dN" (port), "a" (val)); }

static inline void IoWriteWordOnPort(ushort port, ushort val)
{ asm volatile ("outw %1, %0" : : "dN" (port), "a" (val)); }

static inline void IoWriteDWordOnPort(ushort port, uint val)
{ asm volatile ("outl %1, %0" : : "dN" (port), "a" (val)); }

static inline uchar IoReadByteFromPort(ushort port) {
    uchar ret;
    asm volatile ("inb %1, %0" : "=a"(ret) : "Nd"(port));
    return ret;
}

static inline ushort IoReadWordFromPort(ushort port) {
    ushort ret;
    asm volatile ("inw %1, %0" : "=a"(ret) : "Nd"(port));
    return ret;
}

static inline ushort IoReadDWordFromPort(ushort port) {
    uint ret;
    asm volatile ("inl %1, %0" : "=a"(ret) : "Nd"(port));
    return ret;
}

//------------------------------------------//
//                Misc. I/O                 //
//------------------------------------------//

//
// Wait for completion of some I/O operation
// Port 0x80 is used for 'checkpoints' during POST
//
#define IoWaitCompletion() IoWriteByteOnPort(0x80, 0)

#endif