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[/] [or1k_soc_on_altera_embedded_dev_kit/] [trunk/] [linux-2.6/] [linux-2.6.24/] [arch/] [powerpc/] [lib/] [checksum_32.S] - Blame information for rev 3

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1 3 xianfeng 
/*
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 * This file contains assembly-language implementations
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 * of IP-style 1's complement checksum routines.
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 *
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 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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 *
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 *  This program is free software; you can redistribute it and/or
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 *  modify it under the terms of the GNU General Public License
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 *  as published by the Free Software Foundation; either version
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 *  2 of the License, or (at your option) any later version.
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 *
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 * Severely hacked about by Paul Mackerras (paulus@cs.anu.edu.au).
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 */
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#include
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#include
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#include
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#include
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        .text
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/*
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 * ip_fast_csum(buf, len) -- Optimized for IP header
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 * len is in words and is always >= 5.
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 */
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_GLOBAL(ip_fast_csum)
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        lwz     r0,0(r3)
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        lwzu    r5,4(r3)
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        addic.  r4,r4,-2
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        addc    r0,r0,r5
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        mtctr   r4
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        blelr-
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1:      lwzu    r4,4(r3)
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        adde    r0,r0,r4
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        bdnz    1b
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        addze   r0,r0           /* add in final carry */
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        rlwinm  r3,r0,16,0,31   /* fold two halves together */
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        add     r3,r0,r3
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        not     r3,r3
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        srwi    r3,r3,16
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        blr
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/*
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 * Compute checksum of TCP or UDP pseudo-header:
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 *   csum_tcpudp_magic(saddr, daddr, len, proto, sum)
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 */
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_GLOBAL(csum_tcpudp_magic)
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        rlwimi  r5,r6,16,0,15   /* put proto in upper half of len */
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        addc    r0,r3,r4        /* add 4 32-bit words together */
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        adde    r0,r0,r5
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        adde    r0,r0,r7
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        addze   r0,r0           /* add in final carry */
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        rlwinm  r3,r0,16,0,31   /* fold two halves together */
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        add     r3,r0,r3
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        not     r3,r3
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        srwi    r3,r3,16
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        blr
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/*
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 * computes the checksum of a memory block at buff, length len,
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 * and adds in "sum" (32-bit)
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 *
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 * csum_partial(buff, len, sum)
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 */
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_GLOBAL(csum_partial)
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        addic   r0,r5,0
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        subi    r3,r3,4
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        srwi.   r6,r4,2
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        beq     3f              /* if we're doing < 4 bytes */
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        andi.   r5,r3,2         /* Align buffer to longword boundary */
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        beq+    1f
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        lhz     r5,4(r3)        /* do 2 bytes to get aligned */
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        addi    r3,r3,2
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        subi    r4,r4,2
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        addc    r0,r0,r5
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        srwi.   r6,r4,2         /* # words to do */
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        beq     3f
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1:      mtctr   r6
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2:      lwzu    r5,4(r3)        /* the bdnz has zero overhead, so it should */
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        adde    r0,r0,r5        /* be unnecessary to unroll this loop */
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        bdnz    2b
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        andi.   r4,r4,3
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3:      cmpwi   0,r4,2
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        blt+    4f
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        lhz     r5,4(r3)
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        addi    r3,r3,2
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        subi    r4,r4,2
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        adde    r0,r0,r5
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4:      cmpwi   0,r4,1
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        bne+    5f
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        lbz     r5,4(r3)
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        slwi    r5,r5,8         /* Upper byte of word */
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        adde    r0,r0,r5
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5:      addze   r3,r0           /* add in final carry */
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        blr
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/*
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 * Computes the checksum of a memory block at src, length len,
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 * and adds in "sum" (32-bit), while copying the block to dst.
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 * If an access exception occurs on src or dst, it stores -EFAULT
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 * to *src_err or *dst_err respectively, and (for an error on
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 * src) zeroes the rest of dst.
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 *
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 * csum_partial_copy_generic(src, dst, len, sum, src_err, dst_err)
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 */
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_GLOBAL(csum_partial_copy_generic)
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        addic   r0,r6,0
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        subi    r3,r3,4
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        subi    r4,r4,4
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        srwi.   r6,r5,2
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        beq     3f              /* if we're doing < 4 bytes */
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        andi.   r9,r4,2         /* Align dst to longword boundary */
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        beq+    1f
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81:     lhz     r6,4(r3)        /* do 2 bytes to get aligned */
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        addi    r3,r3,2
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        subi    r5,r5,2
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91:     sth     r6,4(r4)
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        addi    r4,r4,2
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        addc    r0,r0,r6
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        srwi.   r6,r5,2         /* # words to do */
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        beq     3f
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1:      srwi.   r6,r5,4         /* # groups of 4 words to do */
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        beq     10f
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        mtctr   r6
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71:     lwz     r6,4(r3)
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72:     lwz     r9,8(r3)
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73:     lwz     r10,12(r3)
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74:     lwzu    r11,16(r3)
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        adde    r0,r0,r6
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75:     stw     r6,4(r4)
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        adde    r0,r0,r9
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76:     stw     r9,8(r4)
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        adde    r0,r0,r10
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77:     stw     r10,12(r4)
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        adde    r0,r0,r11
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78:     stwu    r11,16(r4)
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        bdnz    71b
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10:     rlwinm. r6,r5,30,30,31  /* # words left to do */
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        beq     13f
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        mtctr   r6
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82:     lwzu    r9,4(r3)
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92:     stwu    r9,4(r4)
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        adde    r0,r0,r9
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        bdnz    82b
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13:     andi.   r5,r5,3
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3:      cmpwi   0,r5,2
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        blt+    4f
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83:     lhz     r6,4(r3)
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        addi    r3,r3,2
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        subi    r5,r5,2
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93:     sth     r6,4(r4)
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        addi    r4,r4,2
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        adde    r0,r0,r6
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4:      cmpwi   0,r5,1
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        bne+    5f
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84:     lbz     r6,4(r3)
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94:     stb     r6,4(r4)
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        slwi    r6,r6,8         /* Upper byte of word */
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        adde    r0,r0,r6
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5:      addze   r3,r0           /* add in final carry */
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        blr
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/* These shouldn't go in the fixup section, since that would
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   cause the ex_table addresses to get out of order. */
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src_error_4:
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        mfctr   r6              /* update # bytes remaining from ctr */
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        rlwimi  r5,r6,4,0,27
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        b       79f
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src_error_1:
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        li      r6,0
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        subi    r5,r5,2
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95:     sth     r6,4(r4)
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        addi    r4,r4,2
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79:     srwi.   r6,r5,2
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        beq     3f
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        mtctr   r6
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src_error_2:
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        li      r6,0
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96:     stwu    r6,4(r4)
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        bdnz    96b
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3:      andi.   r5,r5,3
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        beq     src_error
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src_error_3:
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        li      r6,0
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        mtctr   r5
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        addi    r4,r4,3
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97:     stbu    r6,1(r4)
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        bdnz    97b
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src_error:
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        cmpwi   0,r7,0
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        beq     1f
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        li      r6,-EFAULT
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        stw     r6,0(r7)
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1:      addze   r3,r0
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        blr
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dst_error:
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        cmpwi   0,r8,0
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        beq     1f
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        li      r6,-EFAULT
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        stw     r6,0(r8)
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1:      addze   r3,r0
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        blr
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.section __ex_table,"a"
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        .long   81b,src_error_1
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        .long   91b,dst_error
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        .long   71b,src_error_4
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        .long   72b,src_error_4
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        .long   73b,src_error_4
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        .long   74b,src_error_4
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        .long   75b,dst_error
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        .long   76b,dst_error
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        .long   77b,dst_error
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        .long   78b,dst_error
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        .long   82b,src_error_2
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        .long   92b,dst_error
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        .long   83b,src_error_3
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        .long   93b,dst_error
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        .long   84b,src_error_3
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        .long   94b,dst_error
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        .long   95b,dst_error
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        .long   96b,dst_error
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        .long   97b,dst_error

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