ref: 1e9bb75854a336de2a63f9a4fb4d67dd75d682f1
dir: /sys/src/9/teg2/v7-arch.c/
/* * arm arch v7 routines other than cache-related ones. * * calling this arch-v7.c would confuse the mk scripts, * to which a filename arch*.c is magic. */ #include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h" #include "io.h" #include "arm.h" /* * these routines should be cheap enough that there will * be no hesitation to use them. * * once 5c in-lines vlong ops, just use the vlong versions. */ /* see Hacker's Delight if this isn't obvious */ #define ISPOW2(i) (((i) & ((i) - 1)) == 0) int ispow2(uvlong uvl) { /* see Hacker's Delight if this isn't obvious */ return ISPOW2(uvl); } static int isulpow2(ulong ul) /* temporary speed hack */ { return ISPOW2(ul); } /* * return exponent of smallest power of 2 ≥ n */ int log2(ulong n) { int i; i = BI2BY*BY2WD - 1 - clz(n); if (n == 0 || !ISPOW2(n)) i++; return i; }