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52 lines
1.2 KiB
52 lines
1.2 KiB
4 months ago
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/*
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* memcmp - compare memory
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*
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* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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* See https://llvm.org/LICENSE.txt for license information.
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* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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*/
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#if __ARM_FEATURE_SVE
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/* Assumptions:
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*
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* ARMv8-a, AArch64
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* SVE Available.
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*/
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.arch armv8-a+sve
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.text
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.globl __memcmp_aarch64_sve
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.type __memcmp_aarch64_sve, %function
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.p2align 4
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__memcmp_aarch64_sve:
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mov x3, 0 /* initialize off */
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0: whilelo p0.b, x3, x2 /* while off < max */
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b.none 9f
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ld1b z0.b, p0/z, [x0, x3] /* read vectors bounded by max. */
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ld1b z1.b, p0/z, [x1, x3]
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/* Increment for a whole vector, even if we've only read a partial.
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This is significantly cheaper than INCP, and since OFF is not
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used after the loop it is ok to increment OFF past MAX. */
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incb x3
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cmpne p1.b, p0/z, z0.b, z1.b /* while no inequalities */
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b.none 0b
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/* Found inequality. */
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1: brkb p1.b, p0/z, p1.b /* find first such */
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lasta w0, p1, z0.b /* extract each byte */
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lasta w1, p1, z1.b
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sub x0, x0, x1 /* return comparison */
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ret
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/* Found end-of-count. */
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9: mov x0, 0 /* return equality */
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ret
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.size __memcmp_aarch64_sve, . - __memcmp_aarch64_sve
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#endif
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