mesa: Create _mesa_bitcount_64() to replace i965's brw_count_bits()

The i965 driver already had a function to count bits in a 64-bit uint
(brw_count_bits()), but it was buggy (it only counted the bottom 32
bits) and it was clumsy (it had a strange and broken fallback for
non-GCC-like compilers, which fortunately was never used).  Since Mesa
already has a _mesa_bitcount() function, it seems better to just
create a _mesa_bitcount_64() function rather than special-case this in
the i965 driver.

This patch creates the new _mesa_bitcount_64() function and rewrites
all of the old brw_count_bits() calls to refer to it.

Reviewed-by: Ian Romanick <[email protected]>
Reviewed-by: Eric Anholt <[email protected]>

1 files changed, 13 insertions, 0 deletions

diff --git a/src/mesa/main/imports.c b/src/mesa/main/imports.c
index 8f097195922..345a1c53e2f 100644
--- a/src/mesa/main/imports.c
+++ b/src/mesa/main/imports.c
@@ -527,6 +527,19 @@ _mesa_bitcount(unsigned int n)
    }
    return bits;
 }
+
+/**
+ * Return number of bits set in given 64-bit uint.
+ */
+unsigned int
+_mesa_bitcount_64(uint64_t n)
+{
+   unsigned int bits;
+   for (bits = 0; n > 0; n = n >> 1) {
+      bits += (n & 1);
+   }
+   return bits;
+}
 #endif