/*
 * memcmp - compare memory
 *
 * Copyright (c) 2018, Arm Limited.
 * SPDX-License-Identifier: MIT
 */

/* Assumptions:
 *
 * ARMv8-a, AArch64
 * SVE Available.
 */

	.arch	armv8-a+sve
	.text

	.globl	__memcmp_aarch64_sve
	.type	__memcmp_aarch64_sve, %function
	.p2align 4
__memcmp_aarch64_sve:
	mov	x3, 0			/* initialize off */

0:	whilelo	p0.b, x3, x2		/* while off < max */
	b.none	9f

	ld1b	z0.b, p0/z, [x0, x3]	/* read vectors bounded by max.  */
	ld1b	z1.b, p0/z, [x1, x3]

	/* Increment for a whole vector, even if we've only read a partial.
	   This is significantly cheaper than INCP, and since OFF is not
	   used after the loop it is ok to increment OFF past MAX.  */
	incb	x3

	cmpne	p1.b, p0/z, z0.b, z1.b	/* while no inequalities */
	b.none	0b

	/* Found inequality.  */
1:	brkb	p1.b, p0/z, p1.b	/* find first such */
	lasta	w0, p1, z0.b		/* extract each byte */
	lasta	w1, p1, z1.b
	sub	x0, x0, x1		/* return comparison */
	ret

	/* Found end-of-count.  */
9:	mov	x0, 0			/* return equality */
	ret

	.size	__memcmp_aarch64_sve, . - __memcmp_aarch64_sve
