8677a23d5b
src/arch/x86. Signed-off-by: Stefan Reinauer <stepan@coreboot.org> Acked-by: Patrick Georgi <patrick@georgi-clan.de> git-svn-id: svn://svn.coreboot.org/coreboot/trunk@6161 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
21 lines
316 B
C
21 lines
316 B
C
#ifndef I386_BITOPS_H
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#define I386_BITOPS_H
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/**
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* log2 - Find the truncated log base 2 of x
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*/
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static inline unsigned long log2(unsigned long x)
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{
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unsigned long r = 0;
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__asm__(
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"bsrl %1, %0\n\t"
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"jnz 1f\n\t"
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"movl $-1, %0\n\t"
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"1:\n\t"
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: "=r" (r) : "r" (x));
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return r;
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}
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#endif /* I386_BITOPS_H */
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