c02b4fc9db
Signed-off-by: Stefan Reinauer <stepan@coresystems.de> Acked-by: Ronald G. Minnich <rminnich@gmail.com> git-svn-id: svn://svn.coreboot.org/coreboot/trunk@5266 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
29 lines
589 B
C
29 lines
589 B
C
#undef DEBUG_LOG2
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#ifdef DEBUG_LOG2
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#include <console/console.h>
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#endif
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#include <lib.h>
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/* Assume 8 bits per byte */
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#define CHAR_BIT 8
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unsigned long log2(unsigned long x)
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{
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// assume 8 bits per byte.
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unsigned long i = 1ULL << (sizeof(x)* CHAR_BIT - 1ULL);
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unsigned long pow = sizeof(x) * CHAR_BIT - 1ULL;
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if (! x) {
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#ifdef DEBUG_LOG2
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printk(BIOS_WARNING, "%s called with invalid parameter of 0\n",
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__func__);
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#endif
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return -1;
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}
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for(; i > x; i >>= 1, pow--)
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;
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return pow;
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}
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