diff options
Diffstat (limited to 'qemu/roms/u-boot/arch/x86/lib/string.c')
| -rw-r--r-- | qemu/roms/u-boot/arch/x86/lib/string.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/qemu/roms/u-boot/arch/x86/lib/string.c b/qemu/roms/u-boot/arch/x86/lib/string.c new file mode 100644 index 000000000..a1656ccfe --- /dev/null +++ b/qemu/roms/u-boot/arch/x86/lib/string.c @@ -0,0 +1,132 @@ +/* + * Copyright (C) 1991,1992,1993,1997,1998,2003, 2005 Free Software Foundation, Inc. + * This file is part of the GNU C Library. + * Copyright (c) 2011 The Chromium OS Authors. + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +/* From glibc-2.14, sysdeps/i386/memset.c */ + +#include <compiler.h> +#include <asm/string.h> +#include <linux/types.h> + +typedef uint32_t op_t; + +void *memset(void *dstpp, int c, size_t len) +{ + int d0; + unsigned long int dstp = (unsigned long int) dstpp; + + /* This explicit register allocation improves code very much indeed. */ + register op_t x asm("ax"); + + x = (unsigned char) c; + + /* Clear the direction flag, so filling will move forward. */ + asm volatile("cld"); + + /* This threshold value is optimal. */ + if (len >= 12) { + /* Fill X with four copies of the char we want to fill with. */ + x |= (x << 8); + x |= (x << 16); + + /* Adjust LEN for the bytes handled in the first loop. */ + len -= (-dstp) % sizeof(op_t); + + /* + * There are at least some bytes to set. No need to test for + * LEN == 0 in this alignment loop. + */ + + /* Fill bytes until DSTP is aligned on a longword boundary. */ + asm volatile( + "rep\n" + "stosb" /* %0, %2, %3 */ : + "=D" (dstp), "=c" (d0) : + "0" (dstp), "1" ((-dstp) % sizeof(op_t)), "a" (x) : + "memory"); + + /* Fill longwords. */ + asm volatile( + "rep\n" + "stosl" /* %0, %2, %3 */ : + "=D" (dstp), "=c" (d0) : + "0" (dstp), "1" (len / sizeof(op_t)), "a" (x) : + "memory"); + len %= sizeof(op_t); + } + + /* Write the last few bytes. */ + asm volatile( + "rep\n" + "stosb" /* %0, %2, %3 */ : + "=D" (dstp), "=c" (d0) : + "0" (dstp), "1" (len), "a" (x) : + "memory"); + + return dstpp; +} + +#define OP_T_THRES 8 +#define OPSIZ (sizeof(op_t)) + +#define BYTE_COPY_FWD(dst_bp, src_bp, nbytes) \ +do { \ + int __d0; \ + asm volatile( \ + /* Clear the direction flag, so copying goes forward. */ \ + "cld\n" \ + /* Copy bytes. */ \ + "rep\n" \ + "movsb" : \ + "=D" (dst_bp), "=S" (src_bp), "=c" (__d0) : \ + "0" (dst_bp), "1" (src_bp), "2" (nbytes) : \ + "memory"); \ +} while (0) + +#define WORD_COPY_FWD(dst_bp, src_bp, nbytes_left, nbytes) \ +do { \ + int __d0; \ + asm volatile( \ + /* Clear the direction flag, so copying goes forward. */ \ + "cld\n" \ + /* Copy longwords. */ \ + "rep\n" \ + "movsl" : \ + "=D" (dst_bp), "=S" (src_bp), "=c" (__d0) : \ + "0" (dst_bp), "1" (src_bp), "2" ((nbytes) / 4) : \ + "memory"); \ + (nbytes_left) = (nbytes) % 4; \ +} while (0) + +void *memcpy(void *dstpp, const void *srcpp, size_t len) +{ + unsigned long int dstp = (long int)dstpp; + unsigned long int srcp = (long int)srcpp; + + /* Copy from the beginning to the end. */ + + /* If there not too few bytes to copy, use word copy. */ + if (len >= OP_T_THRES) { + /* Copy just a few bytes to make DSTP aligned. */ + len -= (-dstp) % OPSIZ; + BYTE_COPY_FWD(dstp, srcp, (-dstp) % OPSIZ); + + /* Copy from SRCP to DSTP taking advantage of the known + * alignment of DSTP. Number of bytes remaining is put + * in the third argument, i.e. in LEN. This number may + * vary from machine to machine. + */ + WORD_COPY_FWD(dstp, srcp, len, len); + + /* Fall out and copy the tail. */ + } + + /* There are just a few bytes to copy. Use byte memory operations. */ + BYTE_COPY_FWD(dstp, srcp, len); + + return dstpp; +} |