On 6/21/21 6:51 AM, Peter Maydell wrote:
On Mon, 21 Jun 2021 at 14:41, Peter Maydell <peter.mayd...@linaro.org> wrote:
On Mon, 14 Jun 2021 at 09:43, Richard Henderson
<richard.hender...@linaro.org> wrote:
This will eventually simplify front-end usage, and will allow
backends to unset TCG_TARGET_HAS_MEMORY_BSWAP without loss of
optimization.
The argument is added during expansion, not currently exposed
to the front end translators. Non-zero values are not yet
supported by any backends.
Here we say non-zero values are not yet supported by the backend...
Looking at the tcg/README docs, I think what you mean is that
at the moment all the backends assume/require that the caller passes
one of TCG_BSWAP_IZ or (TCG_BSWAP_IZ | TCG_BSWAP_OZ), since the
pre-flags implementation requires the top bytes to be zero and leaves
them that way.
Correct.
But then the parts of your patch that pass in a zero
flags word would be wrong...
The parts that pass in a zero flags word are covered by, from the README:
The flags are ignored -- the argument is present
for consistency with the smaller bswaps.
r~
