[dev.power64] runtime: replace getproccount with simpler code

This runs once. There is no need for inscrutable algorithms.
Also it doesn't compile correctly with 9c.

LGTM=minux
R=minux
CC=golang-codereviews
https://golang.org/cl/130000043

diff --git a/src/pkg/runtime/os_linux.c b/src/pkg/runtime/os_linux.c
index b9ac8c619cbc8122a44b898f022e49c933a0e278..1751ea83b2f18ef3fdc50a57cf9ed20eb521eda7 100644 (file)
--- a/src/pkg/runtime/os_linux.c
+++ b/src/pkg/runtime/os_linux.c
@@ -78,19 +78,22 @@ static int32
 getproccount(void)
 {
        uintptr buf[16], t;
-       int32 r, cnt, i;
+       int32 r, n, i;
 
-       cnt = 0;
        r = runtime·sched_getaffinity(0, sizeof(buf), buf);
-       if(r > 0)
+       if(r <= 0)
+               return 1;
+       n = 0;
        for(i = 0; i < r/sizeof(buf[0]); i++) {
                t = buf[i];
-               t = t - ((t >> 1) & 0x5555555555555555ULL);
-               t = (t & 0x3333333333333333ULL) + ((t >> 2) & 0x3333333333333333ULL);
-               cnt += (int32)((((t + (t >> 4)) & 0xF0F0F0F0F0F0F0FULL) * 0x101010101010101ULL) >> 56);
+               while(t != 0) {
+                       n += t&1;
+                       t >>= 1;
+               }
        }
-
-       return cnt ? cnt : 1;
+       if(n < 1)
+               n = 1;
+       return n;
 }
 
 // Clone, the Linux rfork.