/* * 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 <asm/variant/core.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: */