diff options
Diffstat (limited to 'lib_blackfin/memcpy.S')
| -rw-r--r-- | lib_blackfin/memcpy.S | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/lib_blackfin/memcpy.S b/lib_blackfin/memcpy.S new file mode 100644 index 0000000..a80fe3d --- /dev/null +++ b/lib_blackfin/memcpy.S @@ -0,0 +1,130 @@ +/* + * File: arch/blackfin/lib/memcpy.S + * Based on: + * Author: + * + * Created: + * Description: internal version of memcpy(), issued by the compiler + * to copy blocks of data around. + * This is really memmove() - it has to be able to deal with + * possible overlaps, because that ambiguity is when the compiler + * gives up and calls a function. We have our own, internal version + * so that we get something we trust, even if the user has redefined + * the normal symbol. + * Rev: $Id: memcpy.S 2775 2007-02-21 13:58:44Z hennerich $ + * + * Modified: + * Copyright 2004-2006 Analog Devices Inc. + * + * Bugs: Enter bugs at http://blackfin.uclinux.org/ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see the file COPYING, or write + * to the Free Software Foundation, Inc., + * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + + + +.align 2 + +.globl _memcpy_ASM; +_memcpy_ASM: + CC = R2 <= 0; /* length not positive?*/ + IF CC JUMP .L_P1L2147483647; /* Nothing to do */ + + P0 = R0 ; /* dst*/ + P1 = R1 ; /* src*/ + P2 = R2 ; /* length */ + + /* check for overlapping data */ + CC = R1 < R0; /* src < dst */ + IF !CC JUMP .Lno_overlap; + R3 = R1 + R2; + CC = R0 < R3; /* and dst < src+len */ + IF CC JUMP .Lhas_overlap; + +.Lno_overlap: + /* Check for aligned data.*/ + + R3 = R1 | R0; + R0 = 0x3; + R3 = R3 & R0; + CC = R3; /* low bits set on either address? */ + IF CC JUMP .Lnot_aligned; + + /* Both addresses are word-aligned, so we can copy + at least part of the data using word copies.*/ + P2 = P2 >> 2; + CC = P2 <= 2; + IF !CC JUMP .Lmore_than_seven; + /* less than eight bytes... */ + P2 = R2; + LSETUP(.Lthree_start, .Lthree_end) LC0=P2; + R0 = R1; /* setup src address for return */ +.Lthree_start: + R3 = B[P1++] (X); +.Lthree_end: + B[P0++] = R3; + + RTS; + +.Lmore_than_seven: + /* There's at least eight bytes to copy. */ + P2 += -1; /* because we unroll one iteration */ + LSETUP(.Lword_loop, .Lword_loop) LC0=P2; + R0 = R1; + I1 = P1; + R3 = [I1++]; +.Lword_loop: + MNOP || [P0++] = R3 || R3 = [I1++]; + + [P0++] = R3; + /* Any remaining bytes to copy? */ + R3 = 0x3; + R3 = R2 & R3; + CC = R3 == 0; + P1 = I1; /* in case there's something left, */ + IF !CC JUMP .Lbytes_left; + RTS; +.Lbytes_left: P2 = R3; +.Lnot_aligned: + /* From here, we're copying byte-by-byte. */ + LSETUP (.Lbyte_start , .Lbyte_end) LC0=P2; + R0 = R1; /* Save src address for return */ +.Lbyte_start: + R1 = B[P1++] (X); +.Lbyte_end: + B[P0++] = R1; + +.L_P1L2147483647: + RTS; + +.Lhas_overlap: +/* Need to reverse the copying, because the + * dst would clobber the src. + * Don't bother to work out alignment for + * the reverse case. + */ + R0 = R1; /* save src for later. */ + P0 = P0 + P2; + P0 += -1; + P1 = P1 + P2; + P1 += -1; + LSETUP(.Lover_start, .Lover_end) LC0=P2; +.Lover_start: + R1 = B[P1--] (X); +.Lover_end: + B[P0--] = R1; + + RTS; |