Convert ffs() != 0 callers to ctz32()

There are a number of ffs(3) callers that do roughly:

  bit = ffs(val);
  if (bit) {
      do_something(bit - 1);
  }

This pattern can be converted to ctz32() like this:

  zeroes = ctz32(val);
  if (zeroes != 32) {
      do_something(zeroes);
  }

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1427124571-28598-6-git-send-email-stefanha@redhat.com
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/hw/i2c/omap_i2c.c b/hw/i2c/omap_i2c.c
index d63278dbde..b6f544a221 100644
--- a/hw/i2c/omap_i2c.c
+++ b/hw/i2c/omap_i2c.c
@@ -171,9 +171,13 @@ static uint32_t omap_i2c_read(void *opaque, hwaddr addr)
     case 0x0c:	/* I2C_IV */
         if (s->revision >= OMAP2_INTR_REV)
             break;
-        ret = ffs(s->stat & s->mask);
-        if (ret)
-            s->stat ^= 1 << (ret - 1);
+        ret = ctz32(s->stat & s->mask);
+        if (ret != 32) {
+            s->stat ^= 1 << ret;
+            ret++;
+        } else {
+            ret = 0;
+        }
         omap_i2c_interrupts_update(s);
         return ret;