diff options
Diffstat (limited to 'src/runtime/mbitmap.go')
| -rw-r--r-- | src/runtime/mbitmap.go | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/src/runtime/mbitmap.go b/src/runtime/mbitmap.go index a25995f46f..bae008b432 100644 --- a/src/runtime/mbitmap.go +++ b/src/runtime/mbitmap.go @@ -642,8 +642,7 @@ func (span *mspan) writeHeapBitsSmall(x, dataSize uintptr, typ *_type) (scanSize // The objects here are always really small, so a single load is sufficient. src0 := readUintptr(typ.GCData) - // Create repetitions of the bitmap if we have a small array. - bits := span.elemsize / goarch.PtrSize + // Create repetitions of the bitmap if we have a small slice backing store. scanSize = typ.PtrBytes src := src0 switch typ.Size_ { @@ -658,19 +657,23 @@ func (span *mspan) writeHeapBitsSmall(x, dataSize uintptr, typ *_type) (scanSize // Since we're never writing more than one uintptr's worth of bits, we're either going // to do one or two writes. - dst := span.heapBits() + dst := unsafe.Pointer(span.base() + pageSize - pageSize/goarch.PtrSize/8) o := (x - span.base()) / goarch.PtrSize i := o / ptrBits j := o % ptrBits + bits := span.elemsize / goarch.PtrSize if j+bits > ptrBits { // Two writes. bits0 := ptrBits - j bits1 := bits - bits0 - dst[i+0] = dst[i+0]&(^uintptr(0)>>bits0) | (src << j) - dst[i+1] = dst[i+1]&^((1<<bits1)-1) | (src >> bits0) + dst0 := (*uintptr)(add(dst, (i+0)*goarch.PtrSize)) + dst1 := (*uintptr)(add(dst, (i+1)*goarch.PtrSize)) + *dst0 = (*dst0)&(^uintptr(0)>>bits0) | (src << j) + *dst1 = (*dst1)&^((1<<bits1)-1) | (src >> bits0) } else { // One write. - dst[i] = (dst[i] &^ (((1 << bits) - 1) << j)) | (src << j) + dst := (*uintptr)(add(dst, i*goarch.PtrSize)) + *dst = (*dst)&^(((1<<bits)-1)<<j) | (src << j) } const doubleCheck = false |