func TestXadduintptr(t *testing.T) {
const N = 20
const iter = 100000
inc := uintptr(100)
total := uintptr(0)
runParallel(N, iter, func() {
runtime.Xadduintptr(&total, inc)
})
if want := uintptr(N * iter * inc); want != total {
t.Fatalf("xadduintpr error, want %d, got %d", want, total)
}
total = 0
runParallel(N, iter, func() {
runtime.Xadduintptr(&total, inc)
runtime.Xadduintptr(&total, uintptr(-int64(inc)))
})
if total != 0 {
t.Fatalf("xadduintpr total error, want %d, got %d", 0, total)
}
}
// Tests that xadduintptr correctly updates 64-bit values. The place where
// we actually do so is mstats.go, functions mSysStat{Inc,Dec}.
func TestXadduintptrOnUint64(t *testing.T) {
if runtime.BigEndian != 0 {
// On big endian architectures, we never use xadduintptr to update
// 64-bit values and hence we skip the test. (Note that functions
// mSysStat{Inc,Dec} in mstats.go have explicit checks for
// big-endianness.)
return
}
const inc = 100
val := uint64(0)
runtime.Xadduintptr((*uintptr)(unsafe.Pointer(&val)), inc)
if inc != val {
t.Fatalf("xadduintptr should increase lower-order bits, want %d, got %d", inc, val)
}
}
