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Diffstat (limited to 'arch/xtensa/lib/memcopy.S')
| -rw-r--r-- | arch/xtensa/lib/memcopy.S | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/arch/xtensa/lib/memcopy.S b/arch/xtensa/lib/memcopy.S new file mode 100644 index 00000000000..e8f6d7eb722 --- /dev/null +++ b/arch/xtensa/lib/memcopy.S @@ -0,0 +1,315 @@ +/* + * arch/xtensa/lib/hal/memcopy.S -- Core HAL library functions + * xthal_memcpy and xthal_bcopy + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2002 - 2005 Tensilica Inc. + */ + +#include <xtensa/coreasm.h> + + .macro src_b r, w0, w1 +#ifdef __XTENSA_EB__ + src \r, \w0, \w1 +#else + src \r, \w1, \w0 +#endif + .endm + + .macro ssa8 r +#ifdef __XTENSA_EB__ + ssa8b \r +#else + ssa8l \r +#endif + .endm + + +/* + * void *memcpy(void *dst, const void *src, size_t len); + * void *memmove(void *dst, const void *src, size_t len); + * void *bcopy(const void *src, void *dst, size_t len); + * + * This function is intended to do the same thing as the standard + * library function memcpy() (or bcopy()) for most cases. + * However, where the source and/or destination references + * an instruction RAM or ROM or a data RAM or ROM, that + * source and/or destination will always be accessed with + * 32-bit load and store instructions (as required for these + * types of devices). + * + * !!!!!!! XTFIXME: + * !!!!!!! Handling of IRAM/IROM has not yet + * !!!!!!! been implemented. + * + * The bcopy version is provided here to avoid the overhead + * of an extra call, for callers that require this convention. + * + * The (general case) algorithm is as follows: + * If destination is unaligned, align it by conditionally + * copying 1 and 2 bytes. + * If source is aligned, + * do 16 bytes with a loop, and then finish up with + * 8, 4, 2, and 1 byte copies conditional on the length; + * else (if source is unaligned), + * do the same, but use SRC to align the source data. + * This code tries to use fall-through branches for the common + * case of aligned source and destination and multiple + * of 4 (or 8) length. + * + * Register use: + * a0/ return address + * a1/ stack pointer + * a2/ return value + * a3/ src + * a4/ length + * a5/ dst + * a6/ tmp + * a7/ tmp + * a8/ tmp + * a9/ tmp + * a10/ tmp + * a11/ tmp + */ + + .text + .align 4 + .global bcopy + .type bcopy,@function +bcopy: + entry sp, 16 # minimal stack frame + # a2=src, a3=dst, a4=len + mov a5, a3 # copy dst so that a2 is return value + mov a3, a2 + mov a2, a5 + j .Lcommon # go to common code for memcpy+bcopy + + +/* + * Byte by byte copy + */ + .align 4 + .byte 0 # 1 mod 4 alignment for LOOPNEZ + # (0 mod 4 alignment for LBEG) +.Lbytecopy: +#if XCHAL_HAVE_LOOPS + loopnez a4, .Lbytecopydone +#else /* !XCHAL_HAVE_LOOPS */ + beqz a4, .Lbytecopydone + add a7, a3, a4 # a7 = end address for source +#endif /* !XCHAL_HAVE_LOOPS */ +.Lnextbyte: + l8ui a6, a3, 0 + addi a3, a3, 1 + s8i a6, a5, 0 + addi a5, a5, 1 +#if !XCHAL_HAVE_LOOPS + blt a3, a7, .Lnextbyte +#endif /* !XCHAL_HAVE_LOOPS */ +.Lbytecopydone: + retw + +/* + * Destination is unaligned + */ + + .align 4 +.Ldst1mod2: # dst is only byte aligned + _bltui a4, 7, .Lbytecopy # do short copies byte by byte + + # copy 1 byte + l8ui a6, a3, 0 + addi a3, a3, 1 + addi a4, a4, -1 + s8i a6, a5, 0 + addi a5, a5, 1 + _bbci.l a5, 1, .Ldstaligned # if dst is now aligned, then + # return to main algorithm +.Ldst2mod4: # dst 16-bit aligned + # copy 2 bytes + _bltui a4, 6, .Lbytecopy # do short copies byte by byte + l8ui a6, a3, 0 + l8ui a7, a3, 1 + addi a3, a3, 2 + addi a4, a4, -2 + s8i a6, a5, 0 + s8i a7, a5, 1 + addi a5, a5, 2 + j .Ldstaligned # dst is now aligned, return to main algorithm + + .align 4 + .global memcpy + .type memcpy,@function +memcpy: + .global memmove + .type memmove,@function +memmove: + + entry sp, 16 # minimal stack frame + # a2/ dst, a3/ src, a4/ len + mov a5, a2 # copy dst so that a2 is return value +.Lcommon: + _bbsi.l a2, 0, .Ldst1mod2 # if dst is 1 mod 2 + _bbsi.l a2, 1, .Ldst2mod4 # if dst is 2 mod 4 +.Ldstaligned: # return here from .Ldst?mod? once dst is aligned + srli a7, a4, 4 # number of loop iterations with 16B + # per iteration + movi a8, 3 # if source is not aligned, + _bany a3, a8, .Lsrcunaligned # then use shifting copy + /* + * Destination and source are word-aligned, use word copy. + */ + # copy 16 bytes per iteration for word-aligned dst and word-aligned src +#if XCHAL_HAVE_LOOPS + loopnez a7, .Loop1done +#else /* !XCHAL_HAVE_LOOPS */ + beqz a7, .Loop1done + slli a8, a7, 4 + add a8, a8, a3 # a8 = end of last 16B source chunk +#endif /* !XCHAL_HAVE_LOOPS */ +.Loop1: + l32i a6, a3, 0 + l32i a7, a3, 4 + s32i a6, a5, 0 + l32i a6, a3, 8 + s32i a7, a5, 4 + l32i a7, a3, 12 + s32i a6, a5, 8 + addi a3, a3, 16 + s32i a7, a5, 12 + addi a5, a5, 16 +#if !XCHAL_HAVE_LOOPS + blt a3, a8, .Loop1 +#endif /* !XCHAL_HAVE_LOOPS */ +.Loop1done: + bbci.l a4, 3, .L2 + # copy 8 bytes + l32i a6, a3, 0 + l32i a7, a3, 4 + addi a3, a3, 8 + s32i a6, a5, 0 + s32i a7, a5, 4 + addi a5, a5, 8 +.L2: + bbsi.l a4, 2, .L3 + bbsi.l a4, 1, .L4 + bbsi.l a4, 0, .L5 + retw +.L3: + # copy 4 bytes + l32i a6, a3, 0 + addi a3, a3, 4 + s32i a6, a5, 0 + addi a5, a5, 4 + bbsi.l a4, 1, .L4 + bbsi.l a4, 0, .L5 + retw +.L4: + # copy 2 bytes + l16ui a6, a3, 0 + addi a3, a3, 2 + s16i a6, a5, 0 + addi a5, a5, 2 + bbsi.l a4, 0, .L5 + retw +.L5: + # copy 1 byte + l8ui a6, a3, 0 + s8i a6, a5, 0 + retw + +/* + * Destination is aligned, Source is unaligned + */ + + .align 4 +.Lsrcunaligned: + _beqz a4, .Ldone # avoid loading anything for zero-length copies + # copy 16 bytes per iteration for word-aligned dst and unaligned src + ssa8 a3 # set shift amount from byte offset +#define SIM_CHECKS_ALIGNMENT 1 /* set to 1 when running on ISS (simulator) with the + lint or ferret client, or 0 to save a few cycles */ +#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT + and a11, a3, a8 # save unalignment offset for below + sub a3, a3, a11 # align a3 +#endif + l32i a6, a3, 0 # load first word +#if XCHAL_HAVE_LOOPS + loopnez a7, .Loop2done +#else /* !XCHAL_HAVE_LOOPS */ + beqz a7, .Loop2done + slli a10, a7, 4 + add a10, a10, a3 # a10 = end of last 16B source chunk +#endif /* !XCHAL_HAVE_LOOPS */ +.Loop2: + l32i a7, a3, 4 + l32i a8, a3, 8 + src_b a6, a6, a7 + s32i a6, a5, 0 + l32i a9, a3, 12 + src_b a7, a7, a8 + s32i a7, a5, 4 + l32i a6, a3, 16 + src_b a8, a8, a9 + s32i a8, a5, 8 + addi a3, a3, 16 + src_b a9, a9, a6 + s32i a9, a5, 12 + addi a5, a5, 16 +#if !XCHAL_HAVE_LOOPS + blt a3, a10, .Loop2 +#endif /* !XCHAL_HAVE_LOOPS */ +.Loop2done: + bbci.l a4, 3, .L12 + # copy 8 bytes + l32i a7, a3, 4 + l32i a8, a3, 8 + src_b a6, a6, a7 + s32i a6, a5, 0 + addi a3, a3, 8 + src_b a7, a7, a8 + s32i a7, a5, 4 + addi a5, a5, 8 + mov a6, a8 +.L12: + bbci.l a4, 2, .L13 + # copy 4 bytes + l32i a7, a3, 4 + addi a3, a3, 4 + src_b a6, a6, a7 + s32i a6, a5, 0 + addi a5, a5, 4 + mov a6, a7 +.L13: +#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT + add a3, a3, a11 # readjust a3 with correct misalignment +#endif + bbsi.l a4, 1, .L14 + bbsi.l a4, 0, .L15 +.Ldone: retw +.L14: + # copy 2 bytes + l8ui a6, a3, 0 + l8ui a7, a3, 1 + addi a3, a3, 2 + s8i a6, a5, 0 + s8i a7, a5, 1 + addi a5, a5, 2 + bbsi.l a4, 0, .L15 + retw +.L15: + # copy 1 byte + l8ui a6, a3, 0 + s8i a6, a5, 0 + retw + +/* + * Local Variables: + * mode:fundamental + * comment-start: "# " + * comment-start-skip: "# *" + * End: + */ |