diff --git a/common/bitutil/bitutil.go b/common/bitutil/bitutil.go index 29ae89d4ea..6756d04be5 100644 --- a/common/bitutil/bitutil.go +++ b/common/bitutil/bitutil.go @@ -8,7 +8,6 @@ package bitutil import ( - "math/bits" "runtime" "unsafe" ) @@ -30,7 +29,7 @@ func XORBytes(dst, a, b []byte) int { func fastXORBytes(dst, a, b []byte) int { n := min(len(b), len(a)) - w := n >> bits.TrailingZeros(uint(wordSize)) + w := n / wordSize if w > 0 { dw := *(*[]uintptr)(unsafe.Pointer(&dst)) @@ -82,21 +81,33 @@ func ANDBytes(dst, a, b []byte) int { // fastANDBytes ands in bulk. It only works on architectures that support // unaligned read/writes. func fastANDBytes(dst, a, b []byte) int { - n := len(a) - if len(b) < n { - n = len(b) - } + n := min(len(b), len(a)) w := n / wordSize + if w > 0 { dw := *(*[]uintptr)(unsafe.Pointer(&dst)) aw := *(*[]uintptr)(unsafe.Pointer(&a)) bw := *(*[]uintptr)(unsafe.Pointer(&b)) - for i := 0; i < w; i++ { + + i := 0 + for i <= w-4 { dw[i] = aw[i] & bw[i] + dw[i+1] = aw[i+1] & bw[i+1] + dw[i+2] = aw[i+2] & bw[i+2] + dw[i+3] = aw[i+3] & bw[i+3] + i += 4 + } + // Handle remaining words + for i < w { + dw[i] = aw[i] & bw[i] + i++ } } - for i := n - n%wordSize; i < n; i++ { - dst[i] = a[i] & b[i] + + // Handle remaining bytes + start := w * wordSize + for i := 0; i < n&(wordSize-1); i++ { + dst[start+i] = a[start+i] & b[start+i] } return n } @@ -104,11 +115,8 @@ func fastANDBytes(dst, a, b []byte) int { // safeANDBytes ands one by one. It works on all architectures, independent if // it supports unaligned read/writes or not. func safeANDBytes(dst, a, b []byte) int { - n := len(a) - if len(b) < n { - n = len(b) - } - for i := 0; i < n; i++ { + n := min(len(b), len(a)) + for i := range n { dst[i] = a[i] & b[i] } return n