py/nlraarch64: Fix dangerous use of input register.

Starting with 2757acf6, the `top` variable in `nlr_jump()` in
`nlraarch64.c` was assigned to register `x19` by the compiler.  However,
the assembly code writes over that register with

    ldp x19, x20, [%0,  #32]

since `%0` is now `x19`. This causes the next line

    ldp lr,  x9,  [%0,  #16]

to load the wrong values.

To fix the issue, we move the value of the `top` variable from an unknown
register to a known register at the beginning of the asm code then only use
known/hard-coded registers after that.

Fixes issue #11754.

Signed-off-by: David Lechner <david@pybricks.com>

0 files changed, 0 insertions, 0 deletions