11f0079c5a
This also drops individual copyright notices, all mentioned authors in that part of the tree are listed in AUTHORS. Change-Id: Ib5a92bb46ff2b9d2928aae3763daec71747044c2 Signed-off-by: Patrick Georgi <pgeorgi@google.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/39284 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net> Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
65 lines
1.5 KiB
C
65 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/* This file is part of the coreboot project. */
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/* From glibc-2.14, sysdeps/i386/memset.c */
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#include <string.h>
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#include <stdint.h>
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typedef uint32_t op_t;
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void *memset(void *dstpp, int c, size_t len)
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{
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int d0;
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unsigned long int dstp = (unsigned long int) dstpp;
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/* This explicit register allocation improves code very much indeed. */
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register op_t x asm("ax");
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x = (unsigned char) c;
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/* Clear the direction flag, so filling will move forward. */
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asm volatile("cld");
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/* This threshold value is optimal. */
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if (len >= 12) {
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/* Fill X with four copies of the char we want to fill with. */
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x |= (x << 8);
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x |= (x << 16);
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/* Adjust LEN for the bytes handled in the first loop. */
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len -= (-dstp) % sizeof(op_t);
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/*
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* There are at least some bytes to set. No need to test for
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* LEN == 0 in this alignment loop.
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*/
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/* Fill bytes until DSTP is aligned on a longword boundary. */
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asm volatile(
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"rep\n"
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"stosb" /* %0, %2, %3 */ :
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"=D" (dstp), "=c" (d0) :
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"0" (dstp), "1" ((-dstp) % sizeof(op_t)), "a" (x) :
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"memory");
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/* Fill longwords. */
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asm volatile(
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"rep\n"
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"stosl" /* %0, %2, %3 */ :
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"=D" (dstp), "=c" (d0) :
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"0" (dstp), "1" (len / sizeof(op_t)), "a" (x) :
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"memory");
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len %= sizeof(op_t);
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}
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/* Write the last few bytes. */
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asm volatile(
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"rep\n"
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"stosb" /* %0, %2, %3 */ :
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"=D" (dstp), "=c" (d0) :
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"0" (dstp), "1" (len), "a" (x) :
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"memory");
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return dstpp;
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}
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