/********************************************************/

/*  ntapi: Native API core library                      */

/*  Copyright (C) 2013--2021  SysDeer Technologies, LLC */

/*  Released under GPLv2 and GPLv3; see COPYING.NTAPI.  */

/********************************************************/

#include <ntapi/nt_status.h>

#include <ntapi/nt_blitter.h>

#include <ntapi/nt_sync.h>

#include <ntapi/ntapi.h>

#include <ntapi/nt_atomic.h>

#include "ntapi_blitter.h"

#include "ntapi_impl.h"

static int32_t __fastcall __blt_bitbite(

	__in	nt_blitter *	blitter,

	__in	unsigned int	bit,

	__in	size_t		byte)

{

	uint32_t	locktry;

	uintptr_t	test;

	uintptr_t	cmp;

	uintptr_t	xchg;

	uintptr_t	mask;

	mask    = ((uintptr_t)1 << bit);

	locktry = blitter->params.lock_tries;

	for (; locktry; locktry--) {

		cmp  = blitter->bitmap[byte] | mask;

		xchg = cmp ^ mask;

		test  = at_locked_cas(

			(intptr_t *)&blitter->bitmap[byte],

			cmp,xchg);

		if (test == cmp) {

			at_locked_dec(&blitter->info.blocks_avail);

			at_locked_inc(&blitter->info.blocks_used);

			return NT_STATUS_SUCCESS;

		} else if (test ^ mask)

			return NT_STATUS_TRANSACTIONAL_CONFLICT;

	}

	if (!locktry) {

		blitter->info.busy = 1;

		blitter->info.lock_tries = blitter->params.lock_tries;

		return NT_STATUS_DEVICE_BUSY;

	}

	return NT_STATUS_MORE_PROCESSING_REQUIRED;

}

static int32_t __fastcall __blt_acquire(

	__in	nt_blitter *	blitter,

	__out	intptr_t *	blkid)

{

	unsigned int	bit;

	uintptr_t		i,n;

	if (blitter->info.blocks_avail == 0)

		return NT_STATUS_ALLOCATE_BUCKET;

	for (n=0,bit=0; blitter->info.blocks_avail && (n < blitter->params.round_trips); n++) {

		for (i=*blkid/(8*sizeof(size_t)); (i<blitter->ptrs); i++)

			if (at_bsf(&bit,blitter->bitmap[i]))

				break;

		if (i == blitter->ptrs)

			return NT_STATUS_ALLOCATE_BUCKET;

		switch (__blt_bitbite(blitter,bit,i)) {

			case NT_STATUS_SUCCESS:

				*blkid = bit + (i * 8 * sizeof(size_t));

				return NT_STATUS_SUCCESS;

			case NT_STATUS_DEVICE_BUSY:

				return NT_STATUS_DEVICE_BUSY;

			default:

				break;

		}

	}

	return NT_STATUS_ALLOCATE_BUCKET;

}

int32_t __fastcall __ntapi_blt_obtain(

	__in	nt_blitter *	blitter,

	__out	intptr_t *	blkid)

{

	unsigned int	bit;

	uintptr_t	i,n;

	uintptr_t	mask;

	if (blitter->info.blocks_avail == 0)

		return NT_STATUS_ALLOCATE_BUCKET;

	else if ((bit = *blkid % (8*sizeof(size_t))) == 0)

		return __blt_acquire(blitter,blkid);

	for (n=0,mask=(uintptr_t)-1; n

		mask ^= ((size_t)1 << n);

	i = *blkid / (8*sizeof(size_t));

	for (n=0; blitter->info.blocks_avail && (n < blitter->params.round_trips); n++) {

		if (!(at_bsf(&bit,(mask & blitter->bitmap[i]))))

			break;

		switch (__blt_bitbite(blitter,bit,i)) {

			case NT_STATUS_SUCCESS:

				*blkid = bit + (i * 8 * sizeof(size_t));

				return NT_STATUS_SUCCESS;

			case NT_STATUS_DEVICE_BUSY:

				return NT_STATUS_DEVICE_BUSY;

			default:

				break;

		}

	}

	*blkid = ++i * 8 * sizeof(size_t);

	return __blt_acquire(blitter,blkid);

}

int32_t __fastcall __ntapi_blt_possess(

	__in	nt_blitter *	blitter,

	__out	intptr_t *	blkid)

{

	int		bit;

	size_t		byte;

	uintptr_t 	test;

	uintptr_t	mask;

	uintptr_t	cmp;

	uintptr_t	xchg;

	bit  = *blkid % (8*sizeof(size_t));

	byte = *blkid / (8*sizeof(size_t));

	mask = (uintptr_t)1 << bit;

	do {

		cmp  = blitter->bitmap[byte];

		xchg = cmp & ~mask;

		test = at_locked_cas(

			(intptr_t *)&blitter->bitmap[byte],

			cmp,xchg);

	} while (test != cmp);

	if (test & mask) {

		at_locked_dec(&blitter->info.blocks_avail);

		at_locked_inc(&blitter->info.blocks_used);

	}

	return NT_STATUS_SUCCESS;

}

int32_t __fastcall __ntapi_blt_acquire(

	__in	nt_blitter *	blitter,

	__out	intptr_t *	blkid)

{

	*blkid = 0;

	return __blt_acquire(blitter,blkid);

}

int32_t __fastcall	__ntapi_blt_release(

	__in	nt_blitter *	blitter,

	__out	intptr_t	blkid)

{

	size_t		i;

	unsigned int	idx;

	uintptr_t	bit;

	i   = blkid / (8 * sizeof(uintptr_t));

	idx = blkid % (8 * sizeof(uintptr_t));

	bit = ((uintptr_t)1 << idx);

	at_locked_or((intptr_t *)&blitter->bitmap[i],bit);

	at_locked_dec(&blitter->info.blocks_used);

	at_locked_inc(&blitter->info.blocks_avail);

	return NT_STATUS_SUCCESS;

}

void * __fastcall __ntapi_blt_get(

	__in	const nt_blitter *	blitter,

	__in	intptr_t		block_id)

{

	size_t * addr = (size_t *)blitter->info.region_addr;

	addr += block_id;

	return addr;

}

void __fastcall __ntapi_blt_set(

	__in	const nt_blitter *	blitter,

	__in	intptr_t		block_id,

	__in	void *			val)

{

	size_t * addr = (size_t *)blitter->info.region_addr;

	addr += block_id;

	*addr = (size_t)val;

	return;

}