1/* 2 * File: arch/blackfin/lib/memcpy.S 3 * Based on: 4 * Author: 5 * 6 * Created: 7 * Description: internal version of memcpy(), issued by the compiler 8 * to copy blocks of data around. 9 * This is really memmove() - it has to be able to deal with 10 * possible overlaps, because that ambiguity is when the compiler 11 * gives up and calls a function. We have our own, internal version 12 * so that we get something we trust, even if the user has redefined 13 * the normal symbol. 14 * 15 * Modified: 16 * Copyright 2004-2006 Analog Devices Inc. 17 * 18 * Bugs: Enter bugs at http://blackfin.uclinux.org/ 19 * 20 * This program is free software; you can redistribute it and/or modify 21 * it under the terms of the GNU General Public License as published by 22 * the Free Software Foundation; either version 2 of the License, or 23 * (at your option) any later version. 24 * 25 * This program is distributed in the hope that it will be useful, 26 * but WITHOUT ANY WARRANTY; without even the implied warranty of 27 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 28 * GNU General Public License for more details. 29 * 30 * You should have received a copy of the GNU General Public License 31 * along with this program; if not, see the file COPYING, or write 32 * to the Free Software Foundation, Inc., 33 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 34 */ 35 36#include <linux/linkage.h> 37 38/* void *memcpy(void *dest, const void *src, size_t n); 39 * R0 = To Address (dest) (leave unchanged to form result) 40 * R1 = From Address (src) 41 * R2 = count 42 * 43 * Note: Favours word alignment 44 */ 45 46#ifdef CONFIG_MEMCPY_L1 47.section .l1.text 48#else 49.text 50#endif 51 52.align 2 53 54ENTRY(_memcpy) 55 CC = R2 <= 0; /* length not positive? */ 56 IF CC JUMP .L_P1L2147483647; /* Nothing to do */ 57 58 P0 = R0 ; /* dst*/ 59 P1 = R1 ; /* src*/ 60 P2 = R2 ; /* length */ 61 62 /* check for overlapping data */ 63 CC = R1 < R0; /* src < dst */ 64 IF !CC JUMP .Lno_overlap; 65 R3 = R1 + R2; 66 CC = R0 < R3; /* and dst < src+len */ 67 IF CC JUMP .Lhas_overlap; 68 69.Lno_overlap: 70 /* Check for aligned data.*/ 71 72 R3 = R1 | R0; 73 R0 = 0x3; 74 R3 = R3 & R0; 75 CC = R3; /* low bits set on either address? */ 76 IF CC JUMP .Lnot_aligned; 77 78 /* Both addresses are word-aligned, so we can copy 79 at least part of the data using word copies.*/ 80 P2 = P2 >> 2; 81 CC = P2 <= 2; 82 IF !CC JUMP .Lmore_than_seven; 83 /* less than eight bytes... */ 84 P2 = R2; 85 LSETUP(.Lthree_start, .Lthree_end) LC0=P2; 86 R0 = R1; /* setup src address for return */ 87.Lthree_start: 88 R3 = B[P1++] (X); 89.Lthree_end: 90 B[P0++] = R3; 91 92 RTS; 93 94.Lmore_than_seven: 95 /* There's at least eight bytes to copy. */ 96 P2 += -1; /* because we unroll one iteration */ 97 LSETUP(.Lword_loops, .Lword_loope) LC0=P2; 98 R0 = R1; 99 I1 = P1; 100 R3 = [I1++]; 101#ifdef ANOMALY_05000202 102.Lword_loops: 103 [P0++] = R3; 104.Lword_loope: 105 R3 = [I1++]; 106#else 107.Lword_loops: 108.Lword_loope: 109 MNOP || [P0++] = R3 || R3 = [I1++]; 110#endif 111 [P0++] = R3; 112 /* Any remaining bytes to copy? */ 113 R3 = 0x3; 114 R3 = R2 & R3; 115 CC = R3 == 0; 116 P1 = I1; /* in case there's something left, */ 117 IF !CC JUMP .Lbytes_left; 118 RTS; 119.Lbytes_left: P2 = R3; 120.Lnot_aligned: 121 /* From here, we're copying byte-by-byte. */ 122 LSETUP (.Lbyte_start, .Lbyte_end) LC0=P2; 123 R0 = R1; /* Save src address for return */ 124.Lbyte_start: 125 R1 = B[P1++] (X); 126.Lbyte_end: 127 B[P0++] = R1; 128 129.L_P1L2147483647: 130 RTS; 131 132.Lhas_overlap: 133 /* Need to reverse the copying, because the 134 * dst would clobber the src. 135 * Don't bother to work out alignment for 136 * the reverse case. 137 */ 138 R0 = R1; /* save src for later. */ 139 P0 = P0 + P2; 140 P0 += -1; 141 P1 = P1 + P2; 142 P1 += -1; 143 LSETUP(.Lover_start, .Lover_end) LC0=P2; 144.Lover_start: 145 R1 = B[P1--] (X); 146.Lover_end: 147 B[P0--] = R1; 148 149 RTS; 150 151ENDPROC(_memcpy) 152