tcg: Add INDEX_op_extract2_{i32,i64}

This will let backends implement the double-word shift operation.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/tcg/README b/tcg/README
index 603f4df..c30e541 100644
--- a/tcg/README
+++ b/tcg/README
@@ -343,6 +343,13 @@ at bit 8.  This operation would be equivalent to
 
 (using an arithmetic right shift).
 
+* extract2_i32/i64 dest, t1, t2, pos
+
+For N = {32,64}, extract an N-bit quantity from the concatenation
+of t2:t1, beginning at pos.  The tcg_gen_extract2_{i32,i64} expander
+accepts 0 <= pos <= N as inputs.  The backend code generator will
+not see either 0 or N as inputs for these opcodes.
+
 * extrl_i64_i32 t0, t1
 
 For 64-bit hosts only, extract the low 32-bits of input T1 and place it