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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.17.0/] [newlib/] [libc/] [machine/] [xscale/] [memset.c] - Blame information for rev 158

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Line No. Rev Author Line
1 148 jeremybenn
#if defined __thumb__
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#include "../../string/memset.c"
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#else
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#include <string.h>
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#include "xscale.h"
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void *
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memset (void *dst, int c, size_t len)
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{
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  int dummy;
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  asm volatile ("tst    %0, #0x3"
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#ifndef __OPTIMIZE_SIZE__
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"\n\
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        beq     1f\n\
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        b       2f\n\
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0:\n\
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        strb    %1, [%0], #1\n\
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        tst     %0, #0x3\n\
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        beq     1f\n\
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2:\n\
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        movs    r3, %2\n\
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        sub     %2, %2, #1\n\
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        bne     0b\n\
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# At this point we know that %2 == len == -1 (since the SUB has already taken\n\
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# place).  If we fall through to the 1: label (as the code used to do), the\n\
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# CMP will detect this negative value and branch to the 2: label.  This will\n\
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# test %2 again, but this time against 0.  The test will fail and the loop\n\
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# at 2: will go on for (almost) ever.  Hence the explicit branch to the end\n\
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# of the hand written assembly code.\n\
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        b       4f\n\
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1:\n\
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        cmp     %2, #0x3\n\
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        bls     2f\n\
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        and     %1, %1, #0xff\n\
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        orr     lr, %1, %1, asl #8\n\
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        cmp     %2, #0xf\n\
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        orr     lr, lr, lr, asl #16\n\
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        bls     1f\n\
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        mov     r3, lr\n\
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        mov     r4, lr\n\
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        mov     r5, lr\n\
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0:\n\
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        sub     %2, %2, #16\n\
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        stmia   %0!, { r3, r4, r5, lr }\n\
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        cmp     %2, #0xf\n\
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        bhi     0b\n\
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1:\n\
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        cmp     %2, #0x7\n\
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        bls     1f\n\
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        mov     r3, lr\n\
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0:\n\
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        sub     %2, %2, #8\n\
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        stmia   %0!, { r3, lr }\n\
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        cmp     %2, #0x7\n\
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        bhi     0b\n\
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1:\n\
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        cmp     %2, #0x3\n\
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        bls     2f\n\
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0:\n\
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        sub     %2, %2, #4\n\
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        str     lr, [%0], #4\n\
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        cmp     %2, #0x3\n\
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        bhi     0b\n\
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"
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#endif /* !__OPTIMIZE_SIZE__ */
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"\n\
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2:\n\
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        movs    r3, %2\n\
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        sub     %2, %2, #1\n\
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        beq     4f\n\
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0:\n\
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        movs    r3, %2\n\
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        sub     %2, %2, #1\n\
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        strb    %1, [%0], #1\n\
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        bne     0b\n\
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4:"
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       : "=&r" (dummy), "=&r" (c), "=&r" (len)
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       : "0" (dst), "1" (c), "2" (len)
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       : "memory", "r3", "r4", "r5", "lr");
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  return dst;
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}
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#endif

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