OpenBLAS/kernel/arm64/snrm2.S

/*******************************************************************************
Copyright (c) 2015, The OpenBLAS Project
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*******************************************************************************/

#define ASSEMBLER
#include "common.h"

#define	N	x0	/* vector length */
#define	X	x1	/* X vector address */
#define	INC_X	x2	/* X stride */
#define I	x5	/* loop variable */

/*******************************************************************************
* Macro definitions
*******************************************************************************/

#define TMPF	s6
#define SSQ	s0
#define TMPVF	{v6.s}[0]
#define SZ	4

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

.macro INIT_F1
	ldr	TMPF, [X], #SZ
	fmul	SSQ, TMPF, TMPF
.endm

.macro KERNEL_F1
	ldr	TMPF, [X], #SZ
	fmul	TMPF, TMPF, TMPF
	fadd	SSQ, SSQ, TMPF
.endm

.macro INIT_F4
	ld1	{v1.4s}, [X], #16
	fmul	v1.4s, v1.4s, v1.4s
	ext	v2.16b, v1.16b, v1.16b, #8
	fadd	v2.2s, v1.2s, v2.2s
	faddp	SSQ, v2.2s
.endm

.macro KERNEL_F4
	ld1	{v1.4s}, [X], #16
	fmul	v1.4s, v1.4s, v1.4s
	ext	v2.16b, v1.16b, v1.16b, #8
	fadd	v2.2s, v1.2s, v2.2s
	faddp	TMPF, v2.2s
	fadd	SSQ, SSQ, TMPF
.endm

.macro INIT_S
	lsl	INC_X, INC_X, #2
	ld1	TMPVF, [X], INC_X
	fmul	SSQ, TMPF, TMPF
.endm

.macro KERNEL_S1
	ld1	TMPVF, [X], INC_X
	fmul	TMPF, TMPF, TMPF
	fadd	SSQ, SSQ, TMPF
.endm

/*******************************************************************************
* End of macro definitions
*******************************************************************************/

	PROLOGUE

	cmp	N, xzr
	ble	nrm2_kernel_zero
	cmp	INC_X, xzr
	ble	nrm2_kernel_zero
	cmp	INC_X, #1
	bne	nrm2_kernel_S_BEGIN

nrm2_kernel_F_BEGIN:

	asr	I, N, #2
	cmp	I, xzr
	beq	nrm2_kernel_F1_INIT

	INIT_F4
	subs	I, I, #1
	beq	nrm2_kernel_F1

nrm2_kernel_F4:

	KERNEL_F4

	subs	I, I, #1
	bne	nrm2_kernel_F4

nrm2_kernel_F1:

	ands	I, N, #3
	ble	nrm2_kernel_L999

nrm2_kernel_F10:

	KERNEL_F1

	subs    I, I, #1
        bne     nrm2_kernel_F10

	b	nrm2_kernel_L999

nrm2_kernel_F1_INIT:
	INIT_F1
	subs	N, N, #1
	b	nrm2_kernel_F1

nrm2_kernel_S_BEGIN:

	INIT_S

	subs	N, N, #1
	ble	nrm2_kernel_L999

	asr	I, N, #2
	cmp	I, xzr
	ble	nrm2_kernel_S1

nrm2_kernel_S4:

	KERNEL_S1
	KERNEL_S1
	KERNEL_S1
	KERNEL_S1

	subs	I, I, #1
	bne	nrm2_kernel_S4

nrm2_kernel_S1:

	ands	I, N, #3
	ble	nrm2_kernel_L999

nrm2_kernel_S10:

	KERNEL_S1

	subs    I, I, #1
	bne     nrm2_kernel_S10

nrm2_kernel_L999:
	fsqrt	SSQ, SSQ
	ret

nrm2_kernel_zero:
	fmov	SSQ, wzr

	ret

	EPILOGUE