Changeset 2037

Timestamp:

Apr 20, 2012, 10:18:00 AM (7 years ago)

Author:

cameron

Message:

Add mask_forward_zeroes/mask_reverse_zeroes

File:

• trunk/lib/bitblock.hpp (modified) (3 diffs)

trunk/lib/bitblock.hpp

@@ -40 +40 @@
 static IDISA_ALWAYS_INLINE uint32_t count_forward_zeroes(BitBlock v);
 static IDISA_ALWAYS_INLINE uint32_t count_reverse_zeroes(BitBlock v);
+static IDISA_ALWAYS_INLINE BitBlock mask_forward_zeroes(uint32_t count);
+static IDISA_ALWAYS_INLINE BitBlock mask_reverse_zeroes(uint32_t count);
 static IDISA_ALWAYS_INLINE uint32_t bitstream_scan(BitBlock * v, uint32_t pos);
 static IDISA_ALWAYS_INLINE BitBlock assert_align(BitBlock v);
@@ -79 +81 @@
 }
 
+IDISA_ALWAYS_INLINE BitBlock mask_forward_zeroes(uint32_t count) {
+        if (count >= sizeof(BitBlock) * 8) return simd<1>::constant<0>();
+        else return bitblock::sll(simd<1>::constant<1>(), convert(count));
+}
+
 IDISA_ALWAYS_INLINE uint32_t count_reverse_zeroes(BitBlock v) {
         union {BitBlock bitblock; scanword_t elems[sizeof(BitBlock)/sizeof(scanword_t)];} u;
@@ -88 +95 @@
         }
         return so_far;
+}
+
+IDISA_ALWAYS_INLINE BitBlock mask_reverse_zeroes(uint32_t count) {
+        if (count >= sizeof(BitBlock) * 8) return simd<1>::constant<0>();
+        else return bitblock::srl(simd<1>::constant<1>(), convert(count));
 }