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cfc86988a8
Currently zero extensions ops are implemented by a and op with a
constant. This is then catched in some backend, and replaced by
a zero extension instruction. While this works well on RISC
machines, this adds a useless register move on non-RISC machines.
Example on x86:
ext16u_i32 r1, r2
is translated into
mov %eax,%ebx
movzwl %bx, %ebx
while the optimized version should be:
movzwl %ax, %ebx
This patch adds ext{8,16,32}u_i{32,64} TCG ops that can be
implemented in the backends to avoid emitting useless register
moves.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Read the documentation in qemu-doc.html. Fabrice Bellard.