52 lines
914 B
C
52 lines
914 B
C
/*
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* arm arch v7 routines other than cache-related ones.
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*
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* calling this arch-v7.c would confuse the mk scripts,
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* to which a filename arch*.c is magic.
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*/
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#include "u.h"
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#include "../port/lib.h"
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#include "mem.h"
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#include "dat.h"
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#include "fns.h"
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#include "../port/error.h"
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#include "io.h"
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#include "arm.h"
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/*
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* these routines should be cheap enough that there will
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* be no hesitation to use them.
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*
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* once 5c in-lines vlong ops, just use the vlong versions.
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*/
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/* see Hacker's Delight if this isn't obvious */
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#define ISPOW2(i) (((i) & ((i) - 1)) == 0)
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int
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ispow2(uvlong uvl)
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{
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/* see Hacker's Delight if this isn't obvious */
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return ISPOW2(uvl);
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}
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static int
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isulpow2(ulong ul) /* temporary speed hack */
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{
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return ISPOW2(ul);
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}
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/*
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* return exponent of smallest power of 2 ≥ n
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*/
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int
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log2(ulong n)
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{
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int i;
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i = BI2BY*BY2WD - 1 - clz(n);
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if (n == 0 || !ISPOW2(n))
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i++;
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return i;
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}
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