diff options
Diffstat (limited to 'arch/xtensa/lib/memcopy.S')
| -rw-r--r-- | arch/xtensa/lib/memcopy.S | 309 |
1 files changed, 284 insertions, 25 deletions
diff --git a/arch/xtensa/lib/memcopy.S b/arch/xtensa/lib/memcopy.S index ea59dcd03866..c48b80acb5f0 100644 --- a/arch/xtensa/lib/memcopy.S +++ b/arch/xtensa/lib/memcopy.S @@ -6,7 +6,7 @@ * License. See the file "COPYING" in the main directory of this archive * for more details. * - * Copyright (C) 2002 - 2005 Tensilica Inc. + * Copyright (C) 2002 - 2012 Tensilica Inc. */ #include <variant/core.h> @@ -27,14 +27,11 @@ #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. + * library function memcpy() 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 @@ -45,9 +42,6 @@ * !!!!!!! 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. @@ -76,17 +70,6 @@ */ .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 @@ -107,7 +90,7 @@ bcopy: s8i a6, a5, 0 addi a5, a5, 1 #if !XCHAL_HAVE_LOOPS - blt a3, a7, .Lnextbyte + bne a3, a7, .Lnextbyte # continue loop if $a3:src != $a7:src_end #endif /* !XCHAL_HAVE_LOOPS */ .Lbytecopydone: retw @@ -144,9 +127,6 @@ bcopy: .global memcpy .type memcpy,@function memcpy: - .global memmove - .type memmove,@function -memmove: entry sp, 16 # minimal stack frame # a2/ dst, a3/ src, a4/ len @@ -182,7 +162,7 @@ memmove: s32i a7, a5, 12 addi a5, a5, 16 #if !XCHAL_HAVE_LOOPS - blt a3, a8, .Loop1 + bne a3, a8, .Loop1 # continue loop if a3:src != a8:src_end #endif /* !XCHAL_HAVE_LOOPS */ .Loop1done: bbci.l a4, 3, .L2 @@ -260,7 +240,7 @@ memmove: s32i a9, a5, 12 addi a5, a5, 16 #if !XCHAL_HAVE_LOOPS - blt a3, a10, .Loop2 + bne a3, a10, .Loop2 # continue loop if a3:src != a10:src_end #endif /* !XCHAL_HAVE_LOOPS */ .Loop2done: bbci.l a4, 3, .L12 @@ -305,6 +285,285 @@ memmove: l8ui a6, a3, 0 s8i a6, a5, 0 retw + + +/* + * void bcopy(const void *src, void *dest, size_t n); + */ + .align 4 + .global bcopy + .type bcopy,@function +bcopy: + entry sp, 16 # minimal stack frame + # a2=src, a3=dst, a4=len + mov a5, a3 + mov a3, a2 + mov a2, a5 + j .Lmovecommon # go to common code for memmove+bcopy + +/* + * void *memmove(void *dst, const void *src, size_t len); + * + * This function is intended to do the same thing as the standard + * library function memmove() 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 (general case) algorithm is as follows: + * If end of source doesn't overlap destination then use memcpy. + * Otherwise do memcpy backwards. + * + * 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 + */ + +/* + * Byte by byte copy + */ + .align 4 + .byte 0 # 1 mod 4 alignment for LOOPNEZ + # (0 mod 4 alignment for LBEG) +.Lbackbytecopy: +#if XCHAL_HAVE_LOOPS + loopnez a4, .Lbackbytecopydone +#else /* !XCHAL_HAVE_LOOPS */ + beqz a4, .Lbackbytecopydone + sub a7, a3, a4 # a7 = start address for source +#endif /* !XCHAL_HAVE_LOOPS */ +.Lbacknextbyte: + addi a3, a3, -1 + l8ui a6, a3, 0 + addi a5, a5, -1 + s8i a6, a5, 0 +#if !XCHAL_HAVE_LOOPS + bne a3, a7, .Lbacknextbyte # continue loop if + # $a3:src != $a7:src_start +#endif /* !XCHAL_HAVE_LOOPS */ +.Lbackbytecopydone: + retw + +/* + * Destination is unaligned + */ + + .align 4 +.Lbackdst1mod2: # dst is only byte aligned + _bltui a4, 7, .Lbackbytecopy # do short copies byte by byte + + # copy 1 byte + addi a3, a3, -1 + l8ui a6, a3, 0 + addi a5, a5, -1 + s8i a6, a5, 0 + addi a4, a4, -1 + _bbci.l a5, 1, .Lbackdstaligned # if dst is now aligned, then + # return to main algorithm +.Lbackdst2mod4: # dst 16-bit aligned + # copy 2 bytes + _bltui a4, 6, .Lbackbytecopy # do short copies byte by byte + addi a3, a3, -2 + l8ui a6, a3, 0 + l8ui a7, a3, 1 + addi a5, a5, -2 + s8i a6, a5, 0 + s8i a7, a5, 1 + addi a4, a4, -2 + j .Lbackdstaligned # dst is now aligned, + # return to main algorithm + + .align 4 + .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 +.Lmovecommon: + sub a6, a5, a3 + bgeu a6, a4, .Lcommon + + add a5, a5, a4 + add a3, a3, a4 + + _bbsi.l a5, 0, .Lbackdst1mod2 # if dst is 1 mod 2 + _bbsi.l a5, 1, .Lbackdst2mod4 # if dst is 2 mod 4 +.Lbackdstaligned: # return here from .Lbackdst?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, .Lbacksrcunaligned # 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, .backLoop1done +#else /* !XCHAL_HAVE_LOOPS */ + beqz a7, .backLoop1done + slli a8, a7, 4 + sub a8, a3, a8 # a8 = start of first 16B source chunk +#endif /* !XCHAL_HAVE_LOOPS */ +.backLoop1: + addi a3, a3, -16 + l32i a7, a3, 12 + l32i a6, a3, 8 + addi a5, a5, -16 + s32i a7, a5, 12 + l32i a7, a3, 4 + s32i a6, a5, 8 + l32i a6, a3, 0 + s32i a7, a5, 4 + s32i a6, a5, 0 +#if !XCHAL_HAVE_LOOPS + bne a3, a8, .backLoop1 # continue loop if a3:src != a8:src_start +#endif /* !XCHAL_HAVE_LOOPS */ +.backLoop1done: + bbci.l a4, 3, .Lback2 + # copy 8 bytes + addi a3, a3, -8 + l32i a6, a3, 0 + l32i a7, a3, 4 + addi a5, a5, -8 + s32i a6, a5, 0 + s32i a7, a5, 4 +.Lback2: + bbsi.l a4, 2, .Lback3 + bbsi.l a4, 1, .Lback4 + bbsi.l a4, 0, .Lback5 + retw +.Lback3: + # copy 4 bytes + addi a3, a3, -4 + l32i a6, a3, 0 + addi a5, a5, -4 + s32i a6, a5, 0 + bbsi.l a4, 1, .Lback4 + bbsi.l a4, 0, .Lback5 + retw +.Lback4: + # copy 2 bytes + addi a3, a3, -2 + l16ui a6, a3, 0 + addi a5, a5, -2 + s16i a6, a5, 0 + bbsi.l a4, 0, .Lback5 + retw +.Lback5: + # copy 1 byte + addi a3, a3, -1 + l8ui a6, a3, 0 + addi a5, a5, -1 + s8i a6, a5, 0 + retw + +/* + * Destination is aligned, Source is unaligned + */ + + .align 4 +.Lbacksrcunaligned: + _beqz a4, .Lbackdone # 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 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, .backLoop2done +#else /* !XCHAL_HAVE_LOOPS */ + beqz a7, .backLoop2done + slli a10, a7, 4 + sub a10, a3, a10 # a10 = start of first 16B source chunk +#endif /* !XCHAL_HAVE_LOOPS */ +.backLoop2: + addi a3, a3, -16 + l32i a7, a3, 12 + l32i a8, a3, 8 + addi a5, a5, -16 + src_b a6, a7, a6 + s32i a6, a5, 12 + l32i a9, a3, 4 + src_b a7, a8, a7 + s32i a7, a5, 8 + l32i a6, a3, 0 + src_b a8, a9, a8 + s32i a8, a5, 4 + src_b a9, a6, a9 + s32i a9, a5, 0 +#if !XCHAL_HAVE_LOOPS + bne a3, a10, .backLoop2 # continue loop if a3:src != a10:src_start +#endif /* !XCHAL_HAVE_LOOPS */ +.backLoop2done: + bbci.l a4, 3, .Lback12 + # copy 8 bytes + addi a3, a3, -8 + l32i a7, a3, 4 + l32i a8, a3, 0 + addi a5, a5, -8 + src_b a6, a7, a6 + s32i a6, a5, 4 + src_b a7, a8, a7 + s32i a7, a5, 0 + mov a6, a8 +.Lback12: + bbci.l a4, 2, .Lback13 + # copy 4 bytes + addi a3, a3, -4 + l32i a7, a3, 0 + addi a5, a5, -4 + src_b a6, a7, a6 + s32i a6, a5, 0 + mov a6, a7 +.Lback13: +#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT + add a3, a3, a11 # readjust a3 with correct misalignment +#endif + bbsi.l a4, 1, .Lback14 + bbsi.l a4, 0, .Lback15 +.Lbackdone: + retw +.Lback14: + # copy 2 bytes + addi a3, a3, -2 + l8ui a6, a3, 0 + l8ui a7, a3, 1 + addi a5, a5, -2 + s8i a6, a5, 0 + s8i a7, a5, 1 + bbsi.l a4, 0, .Lback15 + retw +.Lback15: + # copy 1 byte + addi a3, a3, -1 + addi a5, a5, -1 + l8ui a6, a3, 0 + s8i a6, a5, 0 + retw + /* * Local Variables: |
