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      1 /*
      2  * internal version of memcpy(), issued by the compiler to copy blocks of
      3  * data around. This is really memmove() - it has to be able to deal with
      4  * possible overlaps, because that ambiguity is when the compiler gives up
      5  * and calls a function. We have our own, internal version so that we get
      6  * something we trust, even if the user has redefined the normal symbol.
      7  *
      8  * Copyright 2004-2009 Analog Devices Inc.
      9  *
     10  * Licensed under the Clear BSD license or the GPL-2 (or later)
     11  */
     12 
     13 #include <linux/linkage.h>
     14 
     15 /* void *memcpy(void *dest, const void *src, size_t n);
     16  * R0 = To Address (dest) (leave unchanged to form result)
     17  * R1 = From Address (src)
     18  * R2 = count
     19  *
     20  * Note: Favours word alignment
     21  */
     22 
     23 #ifdef CONFIG_MEMCPY_L1
     24 .section .l1.text
     25 #else
     26 .text
     27 #endif
     28 
     29 .align 2
     30 
     31 ENTRY(_memcpy)
     32 	CC = R2 <=  0;	/* length not positive? */
     33 	IF CC JUMP .L_P1L2147483647;	/* Nothing to do */
     34 
     35 	P0 = R0 ;	/* dst*/
     36 	P1 = R1 ;	/* src*/
     37 	P2 = R2 ;	/* length */
     38 
     39 	/* check for overlapping data */
     40 	CC = R1 < R0;	/* src < dst */
     41 	IF !CC JUMP .Lno_overlap;
     42 	R3 = R1 + R2;
     43 	CC = R0 < R3;	/* and dst < src+len */
     44 	IF CC JUMP .Lhas_overlap;
     45 
     46 .Lno_overlap:
     47 	/* Check for aligned data.*/
     48 
     49 	R3 = R1 | R0;
     50 	R1 = 0x3;
     51 	R3 = R3 & R1;
     52 	CC = R3;	/* low bits set on either address? */
     53 	IF CC JUMP .Lnot_aligned;
     54 
     55 	/* Both addresses are word-aligned, so we can copy
     56 	at least part of the data using word copies.*/
     57 	P2 = P2 >> 2;
     58 	CC = P2 <= 2;
     59 	IF !CC JUMP .Lmore_than_seven;
     60 	/* less than eight bytes... */
     61 	P2 = R2;
     62 	LSETUP(.Lthree_start, .Lthree_end) LC0=P2;
     63 .Lthree_start:
     64 	R3 = B[P1++] (X);
     65 .Lthree_end:
     66 	B[P0++] = R3;
     67 
     68 	RTS;
     69 
     70 .Lmore_than_seven:
     71 	/* There's at least eight bytes to copy. */
     72 	P2 += -1;	/* because we unroll one iteration */
     73 	LSETUP(.Lword_loops, .Lword_loope) LC0=P2;
     74 	I1 = P1;
     75 	R3 = [I1++];
     76 #if ANOMALY_05000202
     77 .Lword_loops:
     78 	[P0++] = R3;
     79 .Lword_loope:
     80 	R3 = [I1++];
     81 #else
     82 .Lword_loops:
     83 .Lword_loope:
     84 	MNOP || [P0++] = R3 || R3 = [I1++];
     85 #endif
     86 	[P0++] = R3;
     87 	/* Any remaining bytes to copy? */
     88 	R3 = 0x3;
     89 	R3 = R2 & R3;
     90 	CC = R3 == 0;
     91 	P1 = I1;	/* in case there's something left, */
     92 	IF !CC JUMP .Lbytes_left;
     93 	RTS;
     94 .Lbytes_left:	P2 = R3;
     95 .Lnot_aligned:
     96 	/* From here, we're copying byte-by-byte. */
     97 	LSETUP (.Lbyte_start, .Lbyte_end) LC0=P2;
     98 .Lbyte_start:
     99 	R1 = B[P1++] (X);
    100 .Lbyte_end:
    101 	B[P0++] = R1;
    102 
    103 .L_P1L2147483647:
    104 	RTS;
    105 
    106 .Lhas_overlap:
    107 	/* Need to reverse the copying, because the
    108 	 * dst would clobber the src.
    109 	 * Don't bother to work out alignment for
    110 	 * the reverse case.
    111 	 */
    112 	P0 = P0 + P2;
    113 	P0 += -1;
    114 	P1 = P1 + P2;
    115 	P1 += -1;
    116 	LSETUP(.Lover_start, .Lover_end) LC0=P2;
    117 .Lover_start:
    118 	R1 = B[P1--] (X);
    119 .Lover_end:
    120 	B[P0--] = R1;
    121 
    122 	RTS;
    123 
    124 ENDPROC(_memcpy)
    125