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authorNicolai Hähnle <[email protected]>2016-04-22 12:48:19 -0500
committerNicolai Hähnle <[email protected]>2016-04-27 11:16:39 -0500
commit91fb4bb2e999accfca3394a5720516d03868c521 (patch)
tree939ce6b9dea2091e5e01edfc980cbba7e7454f0c /src/gallium/auxiliary
parent504df3a1d791d071259d23b4a99b9b46b1f601af (diff)
gallium/util: add u_bit_consecutive for generating a consecutive range of bits
There are some undefined behavior subtleties, so having a function to match the u_bit_scan_consecutive_range makes sense. Reviewed-by: Marek Olšák <[email protected]>
Diffstat (limited to 'src/gallium/auxiliary')
-rw-r--r--src/gallium/auxiliary/util/u_math.h12
1 files changed, 12 insertions, 0 deletions
diff --git a/src/gallium/auxiliary/util/u_math.h b/src/gallium/auxiliary/util/u_math.h
index 4e58e505572..ecb1d636fcc 100644
--- a/src/gallium/auxiliary/util/u_math.h
+++ b/src/gallium/auxiliary/util/u_math.h
@@ -545,6 +545,18 @@ u_bit_scan_consecutive_range64(uint64_t *mask, int *start, int *count)
*mask &= ~(((1llu << *count) - 1) << *start);
}
+/* Returns a bitfield in which the first count bits starting at start are
+ * set.
+ */
+static inline unsigned
+u_bit_consecutive(unsigned start, unsigned count)
+{
+ assert(start + count <= 32);
+ if (count == 32)
+ return ~0;
+ return ((1u << count) - 1) << start;
+}
+
/**
* Return float bits.
*/