tcg: Document tcg_qemu_tb_exec() and provide constants for low bit uses

Document tcg_qemu_tb_exec(). In particular, its return value is a
combination of a pointer to the next translation block and some
extra information in the low two bits. Provide some #defines for
the values passed in these bits to improve code clarity.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/exec/gen-icount.h b/include/exec/gen-icount.h
index 8043b3b..c858a73 100644
--- a/include/exec/gen-icount.h
+++ b/include/exec/gen-icount.h
@@ -32,7 +32,7 @@ static void gen_icount_end(TranslationBlock *tb, int num_insns)
     if (use_icount) {
         *icount_arg = num_insns;
         gen_set_label(icount_label);
-        tcg_gen_exit_tb((tcg_target_long)tb + 2);
+        tcg_gen_exit_tb((tcg_target_long)tb + TB_EXIT_ICOUNT_EXPIRED);
     }
 }