diff options
| -rw-r--r-- | gcc/wide-int.cc | 27 | ||||
| -rw-r--r-- | gcc/wide-int.h | 15 |
2 files changed, 42 insertions, 0 deletions
diff --git a/gcc/wide-int.cc b/gcc/wide-int.cc index 1e4c046..24bdce2 100644 --- a/gcc/wide-int.cc +++ b/gcc/wide-int.cc @@ -766,6 +766,33 @@ wi::bswap_large (HOST_WIDE_INT *val, const HOST_WIDE_INT *xval, return canonize (val, len, precision); } +/* Bitreverse the integer represented by XVAL and LEN into VAL. Return + the number of blocks in VAL. Both XVAL and VAL have PRECISION bits. */ +unsigned int +wi::bitreverse_large (HOST_WIDE_INT *val, const HOST_WIDE_INT *xval, + unsigned int len, unsigned int precision) +{ + unsigned int i, s; + + for (i = 0; i < len; i++) + val[i] = 0; + + for (s = 0; s < precision; s++) + { + unsigned int block = s / HOST_BITS_PER_WIDE_INT; + unsigned int offset = s & (HOST_BITS_PER_WIDE_INT - 1); + if (((safe_uhwi (xval, len, block) >> offset) & 1) != 0) + { + unsigned int d = (precision - 1) - s; + block = d / HOST_BITS_PER_WIDE_INT; + offset = d & (HOST_BITS_PER_WIDE_INT - 1); + val[block] |= 1 << offset; + } + } + + return canonize (val, len, precision); +} + /* Fill VAL with a mask where the lower WIDTH bits are ones and the bits above that up to PREC are zeros. The result is inverted if NEGATE is true. Return the number of blocks in VAL. */ diff --git a/gcc/wide-int.h b/gcc/wide-int.h index e4723ad..498d14d 100644 --- a/gcc/wide-int.h +++ b/gcc/wide-int.h @@ -553,6 +553,7 @@ namespace wi UNARY_FUNCTION zext (const T &, unsigned int); UNARY_FUNCTION set_bit (const T &, unsigned int); UNARY_FUNCTION bswap (const T &); + UNARY_FUNCTION bitreverse (const T &); BINARY_FUNCTION min (const T1 &, const T2 &, signop); BINARY_FUNCTION smin (const T1 &, const T2 &); @@ -1748,6 +1749,8 @@ namespace wi unsigned int, unsigned int, unsigned int); unsigned int bswap_large (HOST_WIDE_INT *, const HOST_WIDE_INT *, unsigned int, unsigned int); + unsigned int bitreverse_large (HOST_WIDE_INT *, const HOST_WIDE_INT *, + unsigned int, unsigned int); unsigned int lshift_large (HOST_WIDE_INT *, const HOST_WIDE_INT *, unsigned int, unsigned int, unsigned int); @@ -2281,6 +2284,18 @@ wi::bswap (const T &x) return result; } +/* Bitreverse the integer X. */ +template <typename T> +inline WI_UNARY_RESULT (T) +wi::bitreverse (const T &x) +{ + WI_UNARY_RESULT_VAR (result, val, T, x); + unsigned int precision = get_precision (result); + WIDE_INT_REF_FOR (T) xi (x, precision); + result.set_len (bitreverse_large (val, xi.val, xi.len, precision)); + return result; +} + /* Return the mininum of X and Y, treating them both as having signedness SGN. */ template <typename T1, typename T2> |