Add a "fork" of musl as //fusl.

fusl/arch/powerpc/atomic.h

+#ifndef _INTERNAL_ATOMIC_H
+#define _INTERNAL_ATOMIC_H
+
+#include <stdint.h>
+#include <endian.h>
+
+static inline int a_ctz_l(unsigned long x)
+{
+        static const char debruijn32[32] = {
+                0, 1, 23, 2, 29, 24, 19, 3, 30, 27, 25, 11, 20, 8, 4, 13,
+                31, 22, 28, 18, 26, 10, 7, 12, 21, 17, 9, 6, 16, 5, 15, 14
+        };
+        return debruijn32[(x&-x)*0x076be629 >> 27];
+}
+
+static inline int a_ctz_64(uint64_t x)
+{
+        uint32_t y = x;
+        if (!y) {
+                y = x>>32;
+                return 32 + a_ctz_l(y);
+        }
+        return a_ctz_l(y);
+}
+
+static inline int a_cas(volatile int *p, int t, int s)
+{
+        __asm__("\n"
+                "       sync\n"
+                "1:     lwarx %0, 0, %4\n"
+                "       cmpw %0, %2\n"
+                "       bne 1f\n"
+                "       stwcx. %3, 0, %4\n"
+                "       bne- 1b\n"
+                "       isync\n"
+                "1:     \n"
+                : "=&r"(t), "+m"(*p) : "r"(t), "r"(s), "r"(p) : "cc", "memory" );
+        return t;
+}
+
+static inline void *a_cas_p(volatile void *p, void *t, void *s)
+{
+        return (void *)a_cas(p, (int)t, (int)s);
+}
+
+static inline int a_swap(volatile int *x, int v)
+{
+        int old;
+        do old = *x;
+        while (a_cas(x, old, v) != old);
+        return old;
+}
+
+static inline int a_fetch_add(volatile int *x, int v)
+{
+        int old;
+        do old = *x;
+        while (a_cas(x, old, old+v) != old);
+        return old;
+}
+
+static inline void a_inc(volatile int *x)
+{
+        a_fetch_add(x, 1);
+}
+
+static inline void a_dec(volatile int *x)
+{
+        a_fetch_add(x, -1);
+}
+
+static inline void a_store(volatile int *p, int x)
+{
+        __asm__ __volatile__ ("\n"
+                "       sync\n"
+                "       stw %1, %0\n"
+                "       isync\n"
+                : "=m"(*p) : "r"(x) : "memory" );
+}
+
+#define a_spin a_barrier
+
+static inline void a_barrier()
+{
+        a_cas(&(int){0}, 0, 0);
+}
+
+static inline void a_crash()
+{
+        *(volatile char *)0=0;
+}
+
+static inline void a_and(volatile int *p, int v)
+{
+        int old;
+        do old = *p;
+        while (a_cas(p, old, old&v) != old);
+}
+
+static inline void a_or(volatile int *p, int v)
+{
+        int old;
+        do old = *p;
+        while (a_cas(p, old, old|v) != old);
+}
+
+static inline void a_or_l(volatile void *p, long v)
+{
+        a_or(p, v);
+}
+
+static inline void a_and_64(volatile uint64_t *p, uint64_t v)
+{
+        union { uint64_t v; uint32_t r[2]; } u = { v };
+        a_and((int *)p, u.r[0]);
+        a_and((int *)p+1, u.r[1]);
+}
+
+static inline void a_or_64(volatile uint64_t *p, uint64_t v)
+{
+        union { uint64_t v; uint32_t r[2]; } u = { v };
+        a_or((int *)p, u.r[0]);
+        a_or((int *)p+1, u.r[1]);
+}
+
+#endif