From: Richard Henderson <richard.hender...@linaro.org>
Use simple arithmetic instead of a conditional
move when tbi0 != tbi1.
Reviewed-by: Peter Maydell <peter.mayd...@linaro.org>
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
Message-id: 20210212184902.1251044-22-richard.hender...@linaro.org
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
---
target/arm/translate-a64.c | 25 ++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)
diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 1c4b8d02f3b..b23a8975d54 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -183,17 +183,20 @@ static void gen_top_byte_ignore(DisasContext *s, TCGv_i64
dst,
/* Sign-extend from bit 55. */
tcg_gen_sextract_i64(dst, src, 0, 56);
- if (tbi != 3) {
- TCGv_i64 tcg_zero = tcg_const_i64(0);
-
- /*
- * The two TBI bits differ.
- * If tbi0, then !tbi1: only use the extension if positive.
- * if !tbi0, then tbi1: only use the extension if negative.
- */
- tcg_gen_movcond_i64(tbi == 1 ? TCG_COND_GE : TCG_COND_LT,
- dst, dst, tcg_zero, dst, src);
- tcg_temp_free_i64(tcg_zero);
+ switch (tbi) {
+ case 1:
+ /* tbi0 but !tbi1: only use the extension if positive */
+ tcg_gen_and_i64(dst, dst, src);
+ break;
+ case 2:
+ /* !tbi0 but tbi1: only use the extension if negative */
+ tcg_gen_or_i64(dst, dst, src);
+ break;
+ case 3:
+ /* tbi0 and tbi1: always use the extension */
+ break;
+ default:
+ g_assert_not_reached();
}
}
}
--
2.20.1
