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+/*
+ * 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;