Shift masked

# `shl.masked` / `shr.masked` shift as the chip does (owner, 2026-10-07): the count is masked to the
# width (70 on 64 bits is 6) and bits pushed past the width are cut off; no check site. Plain
# `shl` / `shr` stay checked. "masked" over "wrap", which reads as rotating the bits ("Whatever's accurate").
MAIN {
    let 'b': uint8 = 255;
    let 'x': int64 = 1;
    let 'up': uint8 = 'b' shl.masked 1;        # 510 cut to 8 bits: 254
    let 'far': int64 = 'x' shl.masked 70;      # 70 masked to 6: 64
    let 'down': uint8 = 'b' shr.masked 9;      # 9 masked to 1: 127
    let 'neg': uint32 = (0 minus 1) shr.masked 1;   # -1's bits, then shifted: 2147483647
    std::print.useful['up', " ", 'far', " ", 'down', " ", 'neg', newln];
}