367b8112fe
Move all header files for xtensa to arch/xtensa/include and platform and variant header files to the appropriate arch/xtensa/platforms/ and arch/xtensa/variants/ directories. Moving the files gets also rid of all uses of symlinks in the Makefile. This has been completed already for the majority of the architectures and xtensa is one out of six missing. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Chris Zankel <chris@zankel.net>
161 lines
3.8 KiB
ArmAsm
161 lines
3.8 KiB
ArmAsm
/*
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* arch/xtensa/lib/memset.S
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*
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* ANSI C standard library function memset
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* (Well, almost. .fixup code might return zero.)
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*
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* This file is subject to the terms and conditions of the GNU General
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* Public License. See the file "COPYING" in the main directory of
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* this archive for more details.
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*
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* Copyright (C) 2002 Tensilica Inc.
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*/
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#include <variant/core.h>
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/*
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* void *memset(void *dst, int c, size_t length)
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*
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* The algorithm is as follows:
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* Create a word with c in all byte positions
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* If the destination is aligned,
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* do 16B chucks with a loop, and then finish up with
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* 8B, 4B, 2B, and 1B stores conditional on the length.
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* If destination is unaligned, align it by conditionally
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* setting 1B and 2B and then go to aligned case.
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* This code tries to use fall-through branches for the common
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* case of an aligned destination (except for the branches to
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* the alignment labels).
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*/
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/* Load or store instructions that may cause exceptions use the EX macro. */
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#define EX(insn,reg1,reg2,offset,handler) \
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9: insn reg1, reg2, offset; \
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.section __ex_table, "a"; \
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.word 9b, handler; \
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.previous
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.text
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.align 4
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.global memset
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.type memset,@function
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memset:
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entry sp, 16 # minimal stack frame
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# a2/ dst, a3/ c, a4/ length
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extui a3, a3, 0, 8 # mask to just 8 bits
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slli a7, a3, 8 # duplicate character in all bytes of word
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or a3, a3, a7 # ...
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slli a7, a3, 16 # ...
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or a3, a3, a7 # ...
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mov a5, a2 # copy dst so that a2 is return value
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movi a6, 3 # for alignment tests
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bany a2, a6, .Ldstunaligned # if dst is unaligned
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.L0: # return here from .Ldstunaligned when dst is aligned
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srli a7, a4, 4 # number of loop iterations with 16B
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# per iteration
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bnez a4, .Laligned
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retw
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/*
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* Destination is word-aligned.
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*/
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# set 16 bytes per iteration for word-aligned dst
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.align 4 # 1 mod 4 alignment for LOOPNEZ
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.byte 0 # (0 mod 4 alignment for LBEG)
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.Laligned:
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#if XCHAL_HAVE_LOOPS
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loopnez a7, .Loop1done
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#else /* !XCHAL_HAVE_LOOPS */
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beqz a7, .Loop1done
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slli a6, a7, 4
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add a6, a6, a5 # a6 = end of last 16B chunk
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#endif /* !XCHAL_HAVE_LOOPS */
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.Loop1:
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EX(s32i, a3, a5, 0, memset_fixup)
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EX(s32i, a3, a5, 4, memset_fixup)
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EX(s32i, a3, a5, 8, memset_fixup)
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EX(s32i, a3, a5, 12, memset_fixup)
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addi a5, a5, 16
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#if !XCHAL_HAVE_LOOPS
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blt a5, a6, .Loop1
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#endif /* !XCHAL_HAVE_LOOPS */
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.Loop1done:
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bbci.l a4, 3, .L2
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# set 8 bytes
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EX(s32i, a3, a5, 0, memset_fixup)
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EX(s32i, a3, a5, 4, memset_fixup)
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addi a5, a5, 8
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.L2:
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bbci.l a4, 2, .L3
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# set 4 bytes
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EX(s32i, a3, a5, 0, memset_fixup)
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addi a5, a5, 4
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.L3:
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bbci.l a4, 1, .L4
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# set 2 bytes
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EX(s16i, a3, a5, 0, memset_fixup)
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addi a5, a5, 2
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.L4:
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bbci.l a4, 0, .L5
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# set 1 byte
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EX(s8i, a3, a5, 0, memset_fixup)
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.L5:
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.Lret1:
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retw
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/*
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* Destination is unaligned
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*/
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.Ldstunaligned:
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bltui a4, 8, .Lbyteset # do short copies byte by byte
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bbci.l a5, 0, .L20 # branch if dst alignment half-aligned
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# dst is only byte aligned
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# set 1 byte
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EX(s8i, a3, a5, 0, memset_fixup)
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addi a5, a5, 1
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addi a4, a4, -1
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# now retest if dst aligned
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bbci.l a5, 1, .L0 # if now aligned, return to main algorithm
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.L20:
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# dst half-aligned
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# set 2 bytes
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EX(s16i, a3, a5, 0, memset_fixup)
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addi a5, a5, 2
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addi a4, a4, -2
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j .L0 # dst is now aligned, return to main algorithm
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/*
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* Byte by byte set
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*/
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.align 4
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.byte 0 # 1 mod 4 alignment for LOOPNEZ
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# (0 mod 4 alignment for LBEG)
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.Lbyteset:
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#if XCHAL_HAVE_LOOPS
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loopnez a4, .Lbytesetdone
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#else /* !XCHAL_HAVE_LOOPS */
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beqz a4, .Lbytesetdone
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add a6, a5, a4 # a6 = ending address
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#endif /* !XCHAL_HAVE_LOOPS */
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.Lbyteloop:
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EX(s8i, a3, a5, 0, memset_fixup)
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addi a5, a5, 1
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#if !XCHAL_HAVE_LOOPS
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blt a5, a6, .Lbyteloop
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#endif /* !XCHAL_HAVE_LOOPS */
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.Lbytesetdone:
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retw
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.section .fixup, "ax"
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.align 4
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/* We return zero if a failure occurred. */
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memset_fixup:
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movi a2, 0
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retw
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