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[PULL 09/45] target/arm: Swap argument order for VSHL during decode
From: |
Peter Maydell |
Subject: |
[PULL 09/45] target/arm: Swap argument order for VSHL during decode |
Date: |
Thu, 14 May 2020 15:21:02 +0100 |
From: Richard Henderson <address@hidden>
Rather than perform the argument swap during code generation,
perform it during decode. This means it doesn't have to be
special cased later, and we can share code with aarch64 code
generation. Hopefully the decode comment addresses any confusion
that might arise in between.
Reviewed-by: Peter Maydell <address@hidden>
Signed-off-by: Richard Henderson <address@hidden>
Message-id: address@hidden
Signed-off-by: Peter Maydell <address@hidden>
---
target/arm/neon-dp.decode | 17 +++++++++++++++--
target/arm/translate-neon.inc.c | 3 +--
2 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/target/arm/neon-dp.decode b/target/arm/neon-dp.decode
index ec3a92fe753..593f7fff03d 100644
--- a/target/arm/neon-dp.decode
+++ b/target/arm/neon-dp.decode
@@ -65,8 +65,21 @@ VCGT_U_3s 1111 001 1 0 . .. .... .... 0011 . . . 0
.... @3same
VCGE_S_3s 1111 001 0 0 . .. .... .... 0011 . . . 1 .... @3same
VCGE_U_3s 1111 001 1 0 . .. .... .... 0011 . . . 1 .... @3same
-VSHL_S_3s 1111 001 0 0 . .. .... .... 0100 . . . 0 .... @3same
-VSHL_U_3s 1111 001 1 0 . .. .... .... 0100 . . . 0 .... @3same
+# The _rev suffix indicates that Vn and Vm are reversed. This is
+# the case for shifts. In the Arm ARM these insns are documented
+# with the Vm and Vn fields in their usual places, but in the
+# assembly the operands are listed "backwards", ie in the order
+# Dd, Dm, Dn where other insns use Dd, Dn, Dm. For QEMU we choose
+# to consider Vm and Vn as being in different fields in the insn,
+# which allows us to avoid special-casing shifts in the trans_
+# function code. We would otherwise need to manually swap the operands
+# over to call Neon helper functions that are shared with AArch64,
+# which does not have this odd reversed-operand situation.
+@3same_rev .... ... . . . size:2 .... .... .... . q:1 . . .... \
+ &3same vn=%vm_dp vm=%vn_dp vd=%vd_dp
+
+VSHL_S_3s 1111 001 0 0 . .. .... .... 0100 . . . 0 .... @3same_rev
+VSHL_U_3s 1111 001 1 0 . .. .... .... 0100 . . . 0 .... @3same_rev
VMAX_S_3s 1111 001 0 0 . .. .... .... 0110 . . . 0 .... @3same
VMAX_U_3s 1111 001 1 0 . .. .... .... 0110 . . . 0 .... @3same
diff --git a/target/arm/translate-neon.inc.c b/target/arm/translate-neon.inc.c
index aefeff498a6..416302bcc78 100644
--- a/target/arm/translate-neon.inc.c
+++ b/target/arm/translate-neon.inc.c
@@ -692,8 +692,7 @@ static bool trans_VMUL_p_3s(DisasContext *s, arg_3same *a)
uint32_t rn_ofs, uint32_t rm_ofs, \
uint32_t oprsz, uint32_t maxsz) \
{ \
- /* Note the operation is vshl vd,vm,vn */ \
- tcg_gen_gvec_3(rd_ofs, rm_ofs, rn_ofs, \
+ tcg_gen_gvec_3(rd_ofs, rn_ofs, rm_ofs, \
oprsz, maxsz, &OPARRAY[vece]); \
} \
DO_3SAME(INSN, gen_##INSN##_3s)
--
2.20.1
- [PULL 00/45] target-arm queue, Peter Maydell, 2020/05/14
- [PULL 01/45] target/arm: Use correct GDB XML for M-profile cores, Peter Maydell, 2020/05/14
- [PULL 02/45] target/arm: Create gen_gvec_[us]sra, Peter Maydell, 2020/05/14
- [PULL 03/45] target/arm: Create gen_gvec_{u,s}{rshr,rsra}, Peter Maydell, 2020/05/14
- [PULL 04/45] target/arm: Create gen_gvec_{sri,sli}, Peter Maydell, 2020/05/14
- [PULL 05/45] target/arm: Remove unnecessary range check for VSHL, Peter Maydell, 2020/05/14
- [PULL 06/45] target/arm: Tidy handle_vec_simd_shri, Peter Maydell, 2020/05/14
- [PULL 07/45] target/arm: Create gen_gvec_{ceq,clt,cle,cgt,cge}0, Peter Maydell, 2020/05/14
- [PULL 08/45] target/arm: Create gen_gvec_{mla,mls}, Peter Maydell, 2020/05/14
- [PULL 09/45] target/arm: Swap argument order for VSHL during decode,
Peter Maydell <=
- [PULL 10/45] target/arm: Create gen_gvec_{cmtst,ushl,sshl}, Peter Maydell, 2020/05/14
- [PULL 11/45] target/arm: Create gen_gvec_{uqadd, sqadd, uqsub, sqsub}, Peter Maydell, 2020/05/14
- [PULL 12/45] target/arm: Remove fp_status from helper_{recpe, rsqrte}_u32, Peter Maydell, 2020/05/14
- [PULL 13/45] target/arm: Create gen_gvec_{qrdmla,qrdmls}, Peter Maydell, 2020/05/14
- [PULL 15/45] target/arm: Clear tail in gvec_fmul_idx_*, gvec_fmla_idx_*, Peter Maydell, 2020/05/14
- [PULL 14/45] target/arm: Pass pointer to qc to qrdmla/qrdmls, Peter Maydell, 2020/05/14
- [PULL 16/45] target/arm: Vectorize SABD/UABD, Peter Maydell, 2020/05/14
- [PULL 18/45] aspeed: Add support for the sonorapass-bmc board, Peter Maydell, 2020/05/14
- [PULL 20/45] hw/arm/virt: Introduce a RAS machine option, Peter Maydell, 2020/05/14
- [PULL 21/45] docs: APEI GHES generation and CPER record description, Peter Maydell, 2020/05/14