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[PATCH v6 21/31] target/arm: Improve gen_top_byte_ignore
From: |
Richard Henderson |
Subject: |
[PATCH v6 21/31] target/arm: Improve gen_top_byte_ignore |
Date: |
Tue, 9 Feb 2021 16:02:13 -0800 |
Use simple arithmetic instead of a conditional
move when tbi0 != tbi1.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@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 ffc060e5d7..3ec0dc17d8 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();
}
}
}
--
2.25.1
- [PATCH v6 20/31] linux-user/aarch64: Implement PR_TAGGED_ADDR_ENABLE, (continued)
- [PATCH v6 20/31] linux-user/aarch64: Implement PR_TAGGED_ADDR_ENABLE, Richard Henderson, 2021/02/09
- [PATCH v6 30/31] target/arm: Enable MTE for user-only, Richard Henderson, 2021/02/09
- [PATCH v6 27/31] linux-user/aarch64: Signal SEGV_MTESERR for sync tag check fault, Richard Henderson, 2021/02/09
- [PATCH v6 29/31] target/arm: Add allocation tag storage for user mode, Richard Henderson, 2021/02/09
- [PATCH v6 31/31] tests/tcg/aarch64: Add mte smoke tests, Richard Henderson, 2021/02/09
- [PATCH v6 23/31] linux-user/aarch64: Implement PR_MTE_TCF and PR_MTE_TAG, Richard Henderson, 2021/02/09
- [PATCH v6 19/31] linux-user: Handle tags in lock_user/unlock_user, Richard Henderson, 2021/02/09
- [PATCH v6 22/31] target/arm: Use the proper TBI settings for linux-user, Richard Henderson, 2021/02/09
- [PATCH v6 24/31] linux-user/aarch64: Implement PROT_MTE, Richard Henderson, 2021/02/09
- [PATCH v6 21/31] target/arm: Improve gen_top_byte_ignore,
Richard Henderson <=
- [PATCH v6 26/31] linux-user/aarch64: Pass syndrome to EXC_*_ABORT, Richard Henderson, 2021/02/09
- [PATCH v6 28/31] linux-user/aarch64: Signal SEGV_MTEAERR for async tag check error, Richard Henderson, 2021/02/09
- [PATCH v6 25/31] target/arm: Split out syndrome.h from internals.h, Richard Henderson, 2021/02/09
- Re: [PATCH v6 00/31] target-arm: Implement ARMv8.5-MemTag, user mode, Peter Maydell, 2021/02/11
- Re: [PATCH v6 00/31] target-arm: Implement ARMv8.5-MemTag, user mode, no-reply, 2021/02/11