/*- * Copyright (c) 1997 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Neil A. Carson and Mark Brinicombe * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the NetBSD * Foundation, Inc. and its contributors. * 4. Neither the name of The NetBSD Foundation nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * * Adapted for uClibc from NetBSD _memcpy.S,v 1.6 2003/10/09 * by Erik Andersen <andersen@codepoet.org> */ #include <features.h> #include <endian.h> #include <bits/arm_asm.h> #if !defined(THUMB1_ONLY) /* * This is one fun bit of code ... * Some easy listening music is suggested while trying to understand this * code e.g. Iron Maiden * * For anyone attempting to understand it : * * The core code is implemented here with simple stubs for memcpy() * memmove() and bcopy(). * * All local labels are prefixed with Lmemcpy_ * Following the prefix a label starting f is used in the forward copy code * while a label using b is used in the backwards copy code * The source and destination addresses determine whether a forward or * backward copy is performed. * Separate bits of code are used to deal with the following situations * for both the forward and backwards copy. * unaligned source address * unaligned destination address * Separate copy routines are used to produce an optimised result for each * of these cases. * The copy code will use LDM/STM instructions to copy up to 32 bytes at * a time where possible. * * Note: r12 (aka ip) can be trashed during the function along with * r0-r3 although r0-r2 have defined uses i.e. dest, src, len throughout. * Additional registers are preserved prior to use i.e. r4, r5 & lr * The return value in r0 must be the destination address. * * Apologies for the state of the comments ;-) */ .text .global _memcpy .hidden _memcpy .type _memcpy,%function .align 4 /* XXX: The Thumb-2 conditionals can be removed if/when we require an assembler that supports unified syntax. */ .macro copy regs #if defined(__thumb2__) ittt ge ldmiage r1!, \regs stmiage r0!, \regs #else ldmgeia r1!, \regs stmgeia r0!, \regs #endif .endm .macro copydb regs #if defined(__thumb2__) ittt ge ldmdbge r1!, \regs stmdbge r0!, \regs #else ldmgedb r1!, \regs stmgedb r0!, \regs #endif .endm _memcpy: /* Determine copy direction */ cmp r1, r0 bcc .Lmemcpy_backwards IT(t, eq) /* Quick abort for src=dst */ #if defined(__USE_BX__) bxeq lr #else moveq pc, lr #endif stmdb sp!, {r0, lr} /* memcpy() returns dest addr */ subs r2, r2, #4 blt .Lmemcpy_fl4 /* less than 4 bytes */ ands r12, r0, #3 bne .Lmemcpy_fdestul /* oh unaligned destination addr */ ands r12, r1, #3 bne .Lmemcpy_fsrcul /* oh unaligned source addr */ .Lmemcpy_ft8: /* We have aligned source and destination */ subs r2, r2, #8 blt .Lmemcpy_fl12 /* less than 12 bytes (4 from above) */ subs r2, r2, #0x14 blt .Lmemcpy_fl32 /* less than 32 bytes (12 from above) */ str r4, [sp, #-4]! /* borrow r4 */ /* blat 32 bytes at a time */ /* XXX for really big copies perhaps we should use more registers */ .Lmemcpy_floop32: ldmia r1!, {r3, r4, r12, lr} stmia r0!, {r3, r4, r12, lr} ldmia r1!, {r3, r4, r12, lr} stmia r0!, {r3, r4, r12, lr} subs r2, r2, #0x20 bge .Lmemcpy_floop32 cmn r2, #0x10 /* blat a remaining 16 bytes */ copy "{r3, r4, r12, lr}" subge r2, r2, #0x10 ldr r4, [sp], #4 /* restore r4 */ .Lmemcpy_fl32: adds r2, r2, #0x14 /* blat 12 bytes at a time */ .Lmemcpy_floop12: copy "{r3, r12, lr}" #if defined(__thumb2__) subsge r2, r2, #0x0c #else subges r2, r2, #0x0c #endif bge .Lmemcpy_floop12 .Lmemcpy_fl12: adds r2, r2, #8 blt .Lmemcpy_fl4 subs r2, r2, #4 IT(tt, lt) ldrlt r3, [r1], #4 strlt r3, [r0], #4 copy "{r3, r12}" subge r2, r2, #4 .Lmemcpy_fl4: /* less than 4 bytes to go */ adds r2, r2, #4 #if defined(__thumb2__) it eq popeq {r0, pc} /* done */ #elif defined(__ARM_ARCH_4T__) ldmeqia sp!, {r0, r3} /* done */ bxeq r3 #else ldmeqia sp!, {r0, pc} /* done */ #endif /* copy the crud byte at a time */ cmp r2, #2 ldrb r3, [r1], #1 strb r3, [r0], #1 #if defined(__thumb2__) itt ge ldrbge r3, [r1], #1 strbge r3, [r0], #1 itt gt ldrbgt r3, [r1], #1 strbgt r3, [r0], #1 #else ldrgeb r3, [r1], #1 strgeb r3, [r0], #1 ldrgtb r3, [r1], #1 strgtb r3, [r0], #1 #endif #if defined(__ARM_ARCH_4T__) ldmia sp!, {r0, r3} bx r3 #else ldmia sp!, {r0, pc} #endif /* erg - unaligned destination */ .Lmemcpy_fdestul: rsb r12, r12, #4 cmp r12, #2 /* align destination with byte copies */ ldrb r3, [r1], #1 strb r3, [r0], #1 #if defined(__thumb2__) itt ge ldrbge r3, [r1], #1 strbge r3, [r0], #1 itt gt ldrbgt r3, [r1], #1 strbgt r3, [r0], #1 #else ldrgeb r3, [r1], #1 strgeb r3, [r0], #1 ldrgtb r3, [r1], #1 strgtb r3, [r0], #1 #endif subs r2, r2, r12 blt .Lmemcpy_fl4 /* less the 4 bytes */ ands r12, r1, #3 beq .Lmemcpy_ft8 /* we have an aligned source */ /* erg - unaligned source */ /* This is where it gets nasty ... */ .Lmemcpy_fsrcul: bic r1, r1, #3 ldr lr, [r1], #4 cmp r12, #2 bgt .Lmemcpy_fsrcul3 beq .Lmemcpy_fsrcul2 cmp r2, #0x0c blt .Lmemcpy_fsrcul1loop4 sub r2, r2, #0x0c stmdb sp!, {r4, r5} .Lmemcpy_fsrcul1loop16: #if __BYTE_ORDER == __BIG_ENDIAN mov r3, lr, lsl #8 ldmia r1!, {r4, r5, r12, lr} orr r3, r3, r4, lsr #24 mov r4, r4, lsl #8 orr r4, r4, r5, lsr #24 mov r5, r5, lsl #8 orr r5, r5, r12, lsr #24 mov r12, r12, lsl #8 orr r12, r12, lr, lsr #24 #else mov r3, lr, lsr #8 ldmia r1!, {r4, r5, r12, lr} orr r3, r3, r4, lsl #24 mov r4, r4, lsr #8 orr r4, r4, r5, lsl #24 mov r5, r5, lsr #8 orr r5, r5, r12, lsl #24 mov r12, r12, lsr #8 orr r12, r12, lr, lsl #24 #endif stmia r0!, {r3-r5, r12} subs r2, r2, #0x10 bge .Lmemcpy_fsrcul1loop16 ldmia sp!, {r4, r5} adds r2, r2, #0x0c blt .Lmemcpy_fsrcul1l4 .Lmemcpy_fsrcul1loop4: #if __BYTE_ORDER == __BIG_ENDIAN mov r12, lr, lsl #8 ldr lr, [r1], #4 orr r12, r12, lr, lsr #24 #else mov r12, lr, lsr #8 ldr lr, [r1], #4 orr r12, r12, lr, lsl #24 #endif str r12, [r0], #4 subs r2, r2, #4 bge .Lmemcpy_fsrcul1loop4 .Lmemcpy_fsrcul1l4: sub r1, r1, #3 b .Lmemcpy_fl4 .Lmemcpy_fsrcul2: cmp r2, #0x0c blt .Lmemcpy_fsrcul2loop4 sub r2, r2, #0x0c stmdb sp!, {r4, r5} .Lmemcpy_fsrcul2loop16: #if __BYTE_ORDER == __BIG_ENDIAN mov r3, lr, lsl #16 ldmia r1!, {r4, r5, r12, lr} orr r3, r3, r4, lsr #16 mov r4, r4, lsl #16 orr r4, r4, r5, lsr #16 mov r5, r5, lsl #16 orr r5, r5, r12, lsr #16 mov r12, r12, lsl #16 orr r12, r12, lr, lsr #16 #else mov r3, lr, lsr #16 ldmia r1!, {r4, r5, r12, lr} orr r3, r3, r4, lsl #16 mov r4, r4, lsr #16 orr r4, r4, r5, lsl #16 mov r5, r5, lsr #16 orr r5, r5, r12, lsl #16 mov r12, r12, lsr #16 orr r12, r12, lr, lsl #16 #endif stmia r0!, {r3-r5, r12} subs r2, r2, #0x10 bge .Lmemcpy_fsrcul2loop16 ldmia sp!, {r4, r5} adds r2, r2, #0x0c blt .Lmemcpy_fsrcul2l4 .Lmemcpy_fsrcul2loop4: #if __BYTE_ORDER == __BIG_ENDIAN mov r12, lr, lsl #16 ldr lr, [r1], #4 orr r12, r12, lr, lsr #16 #else mov r12, lr, lsr #16 ldr lr, [r1], #4 orr r12, r12, lr, lsl #16 #endif str r12, [r0], #4 subs r2, r2, #4 bge .Lmemcpy_fsrcul2loop4 .Lmemcpy_fsrcul2l4: sub r1, r1, #2 b .Lmemcpy_fl4 .Lmemcpy_fsrcul3: cmp r2, #0x0c blt .Lmemcpy_fsrcul3loop4 sub r2, r2, #0x0c stmdb sp!, {r4, r5} .Lmemcpy_fsrcul3loop16: #if __BYTE_ORDER == __BIG_ENDIAN mov r3, lr, lsl #24 ldmia r1!, {r4, r5, r12, lr} orr r3, r3, r4, lsr #8 mov r4, r4, lsl #24 orr r4, r4, r5, lsr #8 mov r5, r5, lsl #24 orr r5, r5, r12, lsr #8 mov r12, r12, lsl #24 orr r12, r12, lr, lsr #8 #else mov r3, lr, lsr #24 ldmia r1!, {r4, r5, r12, lr} orr r3, r3, r4, lsl #8 mov r4, r4, lsr #24 orr r4, r4, r5, lsl #8 mov r5, r5, lsr #24 orr r5, r5, r12, lsl #8 mov r12, r12, lsr #24 orr r12, r12, lr, lsl #8 #endif stmia r0!, {r3-r5, r12} subs r2, r2, #0x10 bge .Lmemcpy_fsrcul3loop16 ldmia sp!, {r4, r5} adds r2, r2, #0x0c blt .Lmemcpy_fsrcul3l4 .Lmemcpy_fsrcul3loop4: #if __BYTE_ORDER == __BIG_ENDIAN mov r12, lr, lsl #24 ldr lr, [r1], #4 orr r12, r12, lr, lsr #8 #else mov r12, lr, lsr #24 ldr lr, [r1], #4 orr r12, r12, lr, lsl #8 #endif str r12, [r0], #4 subs r2, r2, #4 bge .Lmemcpy_fsrcul3loop4 .Lmemcpy_fsrcul3l4: sub r1, r1, #1 b .Lmemcpy_fl4 .Lmemcpy_backwards: add r1, r1, r2 add r0, r0, r2 subs r2, r2, #4 blt .Lmemcpy_bl4 /* less than 4 bytes */ ands r12, r0, #3 bne .Lmemcpy_bdestul /* oh unaligned destination addr */ ands r12, r1, #3 bne .Lmemcpy_bsrcul /* oh unaligned source addr */ .Lmemcpy_bt8: /* We have aligned source and destination */ subs r2, r2, #8 blt .Lmemcpy_bl12 /* less than 12 bytes (4 from above) */ stmdb sp!, {r4, lr} subs r2, r2, #0x14 /* less than 32 bytes (12 from above) */ blt .Lmemcpy_bl32 /* blat 32 bytes at a time */ /* XXX for really big copies perhaps we should use more registers */ .Lmemcpy_bloop32: ldmdb r1!, {r3, r4, r12, lr} stmdb r0!, {r3, r4, r12, lr} ldmdb r1!, {r3, r4, r12, lr} stmdb r0!, {r3, r4, r12, lr} subs r2, r2, #0x20 bge .Lmemcpy_bloop32 .Lmemcpy_bl32: cmn r2, #0x10 /* blat a remaining 16 bytes */ copydb "{r3, r4, r12, lr}" subge r2, r2, #0x10 adds r2, r2, #0x14 /* blat a remaining 12 bytes */ copydb "{r3, r12, lr}" subge r2, r2, #0x0c ldmia sp!, {r4, lr} .Lmemcpy_bl12: adds r2, r2, #8 blt .Lmemcpy_bl4 subs r2, r2, #4 IT(tt, lt) ldrlt r3, [r1, #-4]! strlt r3, [r0, #-4]! copydb "{r3, r12}" subge r2, r2, #4 .Lmemcpy_bl4: /* less than 4 bytes to go */ adds r2, r2, #4 IT(t, eq) #if defined(__USE_BX__) bxeq lr #else moveq pc, lr /* done */ #endif /* copy the crud byte at a time */ cmp r2, #2 ldrb r3, [r1, #-1]! strb r3, [r0, #-1]! #ifdef __thumb2__ itt ge ldrbge r3, [r1, #-1]! strbge r3, [r0, #-1]! itt gt ldrbgt r3, [r1, #-1]! strbgt r3, [r0, #-1]! #else ldrgeb r3, [r1, #-1]! strgeb r3, [r0, #-1]! ldrgtb r3, [r1, #-1]! strgtb r3, [r0, #-1]! #endif #if defined(__USE_BX__) bx lr #else mov pc, lr #endif /* erg - unaligned destination */ .Lmemcpy_bdestul: cmp r12, #2 /* align destination with byte copies */ ldrb r3, [r1, #-1]! strb r3, [r0, #-1]! #ifdef __thumb2__ itt ge ldrbge r3, [r1, #-1]! strbge r3, [r0, #-1]! itt gt ldrbgt r3, [r1, #-1]! strbgt r3, [r0, #-1]! #else ldrgeb r3, [r1, #-1]! strgeb r3, [r0, #-1]! ldrgtb r3, [r1, #-1]! strgtb r3, [r0, #-1]! #endif subs r2, r2, r12 blt .Lmemcpy_bl4 /* less than 4 bytes to go */ ands r12, r1, #3 beq .Lmemcpy_bt8 /* we have an aligned source */ /* erg - unaligned source */ /* This is where it gets nasty ... */ .Lmemcpy_bsrcul: bic r1, r1, #3 ldr r3, [r1, #0] cmp r12, #2 blt .Lmemcpy_bsrcul1 beq .Lmemcpy_bsrcul2 cmp r2, #0x0c blt .Lmemcpy_bsrcul3loop4 sub r2, r2, #0x0c stmdb sp!, {r4, r5, lr} .Lmemcpy_bsrcul3loop16: #if __BYTE_ORDER == __BIG_ENDIAN mov lr, r3, lsr #8 ldmdb r1!, {r3-r5, r12} orr lr, lr, r12, lsl #24 mov r12, r12, lsr #8 orr r12, r12, r5, lsl #24 mov r5, r5, lsr #8 orr r5, r5, r4, lsl #24 mov r4, r4, lsr #8 orr r4, r4, r3, lsl #24 #else mov lr, r3, lsl #8 ldmdb r1!, {r3-r5, r12} orr lr, lr, r12, lsr #24 mov r12, r12, lsl #8 orr r12, r12, r5, lsr #24 mov r5, r5, lsl #8 orr r5, r5, r4, lsr #24 mov r4, r4, lsl #8 orr r4, r4, r3, lsr #24 #endif stmdb r0!, {r4, r5, r12, lr} subs r2, r2, #0x10 bge .Lmemcpy_bsrcul3loop16 ldmia sp!, {r4, r5, lr} adds r2, r2, #0x0c blt .Lmemcpy_bsrcul3l4 .Lmemcpy_bsrcul3loop4: #if __BYTE_ORDER == __BIG_ENDIAN mov r12, r3, lsr #8 ldr r3, [r1, #-4]! orr r12, r12, r3, lsl #24 #else mov r12, r3, lsl #8 ldr r3, [r1, #-4]! orr r12, r12, r3, lsr #24 #endif str r12, [r0, #-4]! subs r2, r2, #4 bge .Lmemcpy_bsrcul3loop4 .Lmemcpy_bsrcul3l4: add r1, r1, #3 b .Lmemcpy_bl4 .Lmemcpy_bsrcul2: cmp r2, #0x0c blt .Lmemcpy_bsrcul2loop4 sub r2, r2, #0x0c stmdb sp!, {r4, r5, lr} .Lmemcpy_bsrcul2loop16: #if __BYTE_ORDER == __BIG_ENDIAN mov lr, r3, lsr #16 ldmdb r1!, {r3-r5, r12} orr lr, lr, r12, lsl #16 mov r12, r12, lsr #16 orr r12, r12, r5, lsl #16 mov r5, r5, lsr #16 orr r5, r5, r4, lsl #16 mov r4, r4, lsr #16 orr r4, r4, r3, lsl #16 #else mov lr, r3, lsl #16 ldmdb r1!, {r3-r5, r12} orr lr, lr, r12, lsr #16 mov r12, r12, lsl #16 orr r12, r12, r5, lsr #16 mov r5, r5, lsl #16 orr r5, r5, r4, lsr #16 mov r4, r4, lsl #16 orr r4, r4, r3, lsr #16 #endif stmdb r0!, {r4, r5, r12, lr} subs r2, r2, #0x10 bge .Lmemcpy_bsrcul2loop16 ldmia sp!, {r4, r5, lr} adds r2, r2, #0x0c blt .Lmemcpy_bsrcul2l4 .Lmemcpy_bsrcul2loop4: #if __BYTE_ORDER == __BIG_ENDIAN mov r12, r3, lsr #16 ldr r3, [r1, #-4]! orr r12, r12, r3, lsl #16 #else mov r12, r3, lsl #16 ldr r3, [r1, #-4]! orr r12, r12, r3, lsr #16 #endif str r12, [r0, #-4]! subs r2, r2, #4 bge .Lmemcpy_bsrcul2loop4 .Lmemcpy_bsrcul2l4: add r1, r1, #2 b .Lmemcpy_bl4 .Lmemcpy_bsrcul1: cmp r2, #0x0c blt .Lmemcpy_bsrcul1loop4 sub r2, r2, #0x0c stmdb sp!, {r4, r5, lr} .Lmemcpy_bsrcul1loop32: #if __BYTE_ORDER == __BIG_ENDIAN mov lr, r3, lsr #24 ldmdb r1!, {r3-r5, r12} orr lr, lr, r12, lsl #8 mov r12, r12, lsr #24 orr r12, r12, r5, lsl #8 mov r5, r5, lsr #24 orr r5, r5, r4, lsl #8 mov r4, r4, lsr #24 orr r4, r4, r3, lsl #8 #else mov lr, r3, lsl #24 ldmdb r1!, {r3-r5, r12} orr lr, lr, r12, lsr #8 mov r12, r12, lsl #24 orr r12, r12, r5, lsr #8 mov r5, r5, lsl #24 orr r5, r5, r4, lsr #8 mov r4, r4, lsl #24 orr r4, r4, r3, lsr #8 #endif stmdb r0!, {r4, r5, r12, lr} subs r2, r2, #0x10 bge .Lmemcpy_bsrcul1loop32 ldmia sp!, {r4, r5, lr} adds r2, r2, #0x0c blt .Lmemcpy_bsrcul1l4 .Lmemcpy_bsrcul1loop4: #if __BYTE_ORDER == __BIG_ENDIAN mov r12, r3, lsr #24 ldr r3, [r1, #-4]! orr r12, r12, r3, lsl #8 #else mov r12, r3, lsl #24 ldr r3, [r1, #-4]! orr r12, r12, r3, lsr #8 #endif str r12, [r0, #-4]! subs r2, r2, #4 bge .Lmemcpy_bsrcul1loop4 .Lmemcpy_bsrcul1l4: add r1, r1, #1 b .Lmemcpy_bl4 #else /* THUMB1_ONLY */ /* This is a fairly dumb implementation for when we can't use the 32-bit code above. */ .text .global _memcpy .hidden _memcpy .type _memcpy,%function .align 4 .thumb _memcpy: push {r0, r4} cmp r2, #0 beq .Lmemcpy_exit @ See if we have overlapping regions, and need to reverse the @ direction of the copy cmp r0, r1 bls .Lmemcpy_forwards add r4, r1, r2 cmp r0, r4 bcc .Lmemcpy_backwards .Lmemcpy_forwards: /* Forwards. */ mov r3, r0 eor r3, r1 mov r4, #3 tst r3, r4 bne .Lmemcpy_funaligned cmp r2, #8 bcc .Lmemcpy_funaligned 1: @ copy up to the first word boundary. tst r0, r4 beq 1f ldrb r3, [r1] add r1, r1, #1 strb r3, [r0] add r0, r0, #1 sub r2, r2, #1 b 1b 1: @ Copy aligned words ldr r3, [r1] add r1, r1, #4 str r3, [r0] add r0, r0, #4 sub r2, r2, #4 cmp r2, #4 bcs 1b cmp r2, #0 beq .Lmemcpy_exit .Lmemcpy_funaligned: 1: ldrb r3, [r1] add r1, r1, #1 strb r3, [r0] add r0, r0, #1 sub r2, r2, #1 bne 1b .Lmemcpy_exit: pop {r0, r4} bx lr .Lmemcpy_backwards: add r0, r0, r2 add r1, r1, r2 1: sub r0, r0, #1 sub r1, r1, #1 ldrb r3, [r1] strb r3, [r0] sub r2, r2, #1 bne 1b b .Lmemcpy_exit #endif