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authorEmilio G. Cota <cota@braap.org>2017-04-26 23:29:14 -0400
committerRichard Henderson <rth@twiddle.net>2017-06-05 09:25:42 -0700
commitcedbcb01529cb6cf9a2289cdbebbc63f6149fc18 (patch)
treed66d40f19de1ab12a0e59131fc7b2d88f10bd823 /tcg/README
parent374aae653499f4d405caf32b7fff0c8639113fe4 (diff)
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tcg: Introduce goto_ptr opcode and tcg_gen_lookup_and_goto_ptr
Instead of exporting goto_ptr directly to TCG frontends, export tcg_gen_lookup_and_goto_ptr(), which calls goto_ptr with the pointer returned by the lookup_tb_ptr() helper. This is the only use case we have for goto_ptr and lookup_tb_ptr, so having this function is very convenient. Furthermore, it trivially allows us to avoid calling the lookup helper if goto_ptr is not implemented by the backend. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <1493263764-18657-2-git-send-email-cota@braap.org> Message-Id: <1493263764-18657-3-git-send-email-cota@braap.org> Message-Id: <1493263764-18657-4-git-send-email-cota@braap.org> Message-Id: <1493263764-18657-5-git-send-email-cota@braap.org> [rth: Squashed 4 related commits.] Signed-off-by: Richard Henderson <rth@twiddle.net>
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diff --git a/tcg/README b/tcg/README
index a9858c2..bf49e82 100644
--- a/tcg/README
+++ b/tcg/README
@@ -477,6 +477,14 @@ current TB was linked to this TB. Otherwise execute the next
instructions. Only indices 0 and 1 are valid and tcg_gen_goto_tb may be issued
at most once with each slot index per TB.
+* lookup_and_goto_ptr tb_addr
+
+Look up a TB address ('tb_addr') and jump to it if valid. If not valid,
+jump to the TCG epilogue to go back to the exec loop.
+
+This operation is optional. If the TCG backend does not implement the
+goto_ptr opcode, emitting this op is equivalent to emitting exit_tb(0).
+
* qemu_ld_i32/i64 t0, t1, flags, memidx
* qemu_st_i32/i64 t0, t1, flags, memidx