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- /*
- * linux/arch/unicore32/lib/clear_user.S
- *
- * Code specific to PKUnity SoC and UniCore ISA
- *
- * Copyright (C) 2001-2010 GUAN Xue-tao
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
- #include <linux/linkage.h>
- #include <asm/assembler.h>
- .text
- /* Prototype: int __clear_user(void *addr, size_t sz)
- * Purpose : clear some user memory
- * Params : addr - user memory address to clear
- * : sz - number of bytes to clear
- * Returns : number of bytes NOT cleared
- */
- WEAK(__clear_user)
- stm.w (lr), [sp-]
- stm.w (r1), [sp-]
- mov r2, #0
- csub.a r1, #4
- bsl 2f
- and.a ip, r0, #3
- beq 1f
- csub.a ip, #2
- strusr r2, r0, 1
- strusr r2, r0, 1, el
- strusr r2, r0, 1, sl
- rsub ip, ip, #4
- sub r1, r1, ip @ 7 6 5 4 3 2 1
- 1: sub.a r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7
- strusr r2, r0, 4, ns, rept=2
- bns 1b
- add.a r1, r1, #4 @ 3 2 1 0 -1 -2 -3
- strusr r2, r0, 4, ns
- 2: cand.a r1, #2 @ 1x 1x 0x 0x 1x 1x 0x
- strusr r2, r0, 1, ne, rept=2
- cand.a r1, #1 @ x1 x0 x1 x0 x1 x0 x1
- beq 3f
- USER( stb.u r2, [r0])
- 3: mov r0, #0
- ldm.w (r1), [sp]+
- ldm.w (pc), [sp]+
- ENDPROC(__clear_user)
- .pushsection .fixup,"ax"
- .align 0
- 9001: ldm.w (r0), [sp]+
- ldm.w (pc), [sp]+
- .popsection
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