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#include <stddef.h>
#include <sha1_mb.h>
#include <assert.h>
#include "endian_helper.h"

extern void sha1_aarch64_x1(const uint8_t * data, int num_blocks, uint32_t digest[]);
static inline void sha1_job_x1(SHA1_JOB * job, int blocks)
{
	sha1_aarch64_x1(job->buffer, blocks, job->result_digest);
}

#ifndef min
#define min(a,b)            (((a) < (b)) ? (a) : (b))
#endif

#define SHA1_MB_ASIMD_MAX_LANES	4
void sha1_mb_asimd_x4(SHA1_JOB *, SHA1_JOB *, SHA1_JOB *, SHA1_JOB *, int);

#define LANE_IS_NOT_FINISHED(state,i)  	\
	(((state->lens[i]&(~0xf))!=0) && state->ldata[i].job_in_lane!=NULL)
#define LANE_IS_FINISHED(state,i)  	\
	(((state->lens[i]&(~0xf))==0) && state->ldata[i].job_in_lane!=NULL)
#define	LANE_IS_FREE(state,i)		\
	(((state->lens[i]&(~0xf))==0) && state->ldata[i].job_in_lane==NULL)
#define LANE_IS_INVALID(state,i)	\
	(((state->lens[i]&(~0xf))!=0) && state->ldata[i].job_in_lane==NULL)

void sha1_mb_mgr_init_asimd(SHA1_MB_JOB_MGR * state)
{
	unsigned int i;

	state->unused_lanes = 0xf;
	state->num_lanes_inuse = 0;
	for (i = 0; i < SHA1_MB_ASIMD_MAX_LANES; i++) {
		state->unused_lanes <<= 4;
		state->unused_lanes |= SHA1_MB_ASIMD_MAX_LANES - 1 - i;
		state->lens[i] = i;
		state->ldata[i].job_in_lane = 0;
	}

	// lanes > SHA1_MB_ASIMD_MAX_LANES is invalid lane
	for (; i < SHA1_MAX_LANES; i++) {
		state->lens[i] = 0xf;
		state->ldata[i].job_in_lane = 0;
	}
}

static int sha1_mb_mgr_do_jobs(SHA1_MB_JOB_MGR * state)
{
	int lane_idx, len, i, lanes, blocks;
	int lane_idx_array[SHA1_MAX_LANES];

	if (state->num_lanes_inuse == 0) {
		return -1;
	}
	lanes = 0, len = 0;
	for (i = 0; i < SHA1_MAX_LANES && lanes < state->num_lanes_inuse; i++) {
		if (LANE_IS_NOT_FINISHED(state, i)) {
			if (lanes)
				len = min(len, state->lens[i]);
			else
				len = state->lens[i];
			lane_idx_array[lanes] = i;
			lanes++;
		}
	}

	if (lanes == 0)
		return -1;
	lane_idx = len & 0xf;
	len = len & (~0xf);
	blocks = len >> 4;

	/* for less-than-3-lane job, ASIMD really does not have much advantage
	 * compared to scalar due to wasted >= 50% capacity
	 * therefore we only run ASIMD for 3/4 lanes of data
	 */
	if (lanes == SHA1_MB_ASIMD_MAX_LANES) {
		sha1_mb_asimd_x4(state->ldata[lane_idx_array[0]].job_in_lane,
				 state->ldata[lane_idx_array[1]].job_in_lane,
				 state->ldata[lane_idx_array[2]].job_in_lane,
				 state->ldata[lane_idx_array[3]].job_in_lane, blocks);
	} else if (lanes == 3) {
		/* in case of 3 lanes, apparently ASIMD will still operate as if
		 * there were four lanes of data in processing (waste 25% capacity)
		 * theoretically we can let ASIMD implementation know the number of lanes
		 * so that it could "at least" save some memory loading time
		 * but in practice, we can just pass lane 0 as dummy for similar
		 * cache performance
		 */
		SHA1_JOB dummy;
		dummy.buffer = state->ldata[lane_idx_array[0]].job_in_lane->buffer;
		dummy.len = state->ldata[lane_idx_array[0]].job_in_lane->len;
		sha1_mb_asimd_x4(state->ldata[lane_idx_array[0]].job_in_lane,
				 &dummy,
				 state->ldata[lane_idx_array[1]].job_in_lane,
				 state->ldata[lane_idx_array[2]].job_in_lane, blocks);
	} else {
		sha1_job_x1(state->ldata[lane_idx_array[0]].job_in_lane, blocks);
		if (lanes >= 2) {
			sha1_job_x1(state->ldata[lane_idx_array[1]].job_in_lane, blocks);
		}
	}

	// only return the min length job
	for (i = 0; i < SHA1_MAX_LANES; i++) {
		if (LANE_IS_NOT_FINISHED(state, i)) {
			state->lens[i] -= len;
			state->ldata[i].job_in_lane->len -= len;
			state->ldata[i].job_in_lane->buffer += len << 2;
		}
	}
	return lane_idx;

}

static SHA1_JOB *sha1_mb_mgr_free_lane(SHA1_MB_JOB_MGR * state)
{
	int i;
	SHA1_JOB *ret = NULL;

	for (i = 0; i < SHA1_MB_ASIMD_MAX_LANES; i++) {
		if (LANE_IS_FINISHED(state, i)) {
			state->unused_lanes <<= 4;
			state->unused_lanes |= i;
			state->num_lanes_inuse--;
			ret = state->ldata[i].job_in_lane;
			ret->status = STS_COMPLETED;
			state->ldata[i].job_in_lane = NULL;
			break;
		}
	}
	return ret;
}

static void sha1_mb_mgr_insert_job(SHA1_MB_JOB_MGR * state, SHA1_JOB * job)
{
	int lane_idx;
	// add job into lanes
	lane_idx = state->unused_lanes & 0xf;
	// fatal error
	assert(lane_idx < SHA1_MB_ASIMD_MAX_LANES);
	state->lens[lane_idx] = (job->len << 4) | lane_idx;
	state->ldata[lane_idx].job_in_lane = job;
	state->unused_lanes >>= 4;
	state->num_lanes_inuse++;
}

SHA1_JOB *sha1_mb_mgr_submit_asimd(SHA1_MB_JOB_MGR * state, SHA1_JOB * job)
{
#ifndef NDEBUG
	int lane_idx;
#endif
	SHA1_JOB *ret;

	// add job into lanes
	sha1_mb_mgr_insert_job(state, job);

	ret = sha1_mb_mgr_free_lane(state);
	if (ret != NULL) {
		return ret;
	}
	// submit will wait all lane has data
	if (state->num_lanes_inuse < SHA1_MB_ASIMD_MAX_LANES)
		return NULL;
#ifndef NDEBUG
	lane_idx = sha1_mb_mgr_do_jobs(state);
	assert(lane_idx != -1);
#else
	sha1_mb_mgr_do_jobs(state);
#endif

	// ~ i = lane_idx;
	ret = sha1_mb_mgr_free_lane(state);
	return ret;
}

SHA1_JOB *sha1_mb_mgr_flush_asimd(SHA1_MB_JOB_MGR * state)
{
	SHA1_JOB *ret;
	ret = sha1_mb_mgr_free_lane(state);
	if (ret) {
		return ret;
	}

	sha1_mb_mgr_do_jobs(state);
	return sha1_mb_mgr_free_lane(state);

}