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qemu/target/arm/tcg/vfp.decode
Peter Maydell 76dd36660b target/arm: Correct names of VFP VFNMA and VFNMS insns 
In vfp.decode we have the names of the VFNMA and VFNMS instructions
the wrong way around.  The architecture says that bit 6 is the 'op'
bit, which is 1 for VFNMA and 0 for VFNMS, but we label these two
lines of decode the other way around.  This doesn't cause any
user-visible problem because in the handling of these functions in
translate-vfp.c we give VFNMA the behaviour specified for VFNMS and
vice-versa, but it's confusing when reading the code.

Switch the names of the VFP VFNMA and VFNMS instructions in
the decode file and flip the behaviour also.

NB: the instructions VFMA and VFMS *are* decoded with op=0 for
VFMA and op=1 for VFMS; the confusion probably arose because
we assumed VFNMA and VFNMS to be the same way around.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2536
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20240830152156.2046590-1-peter.maydell@linaro.org
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2024-09-05 13:12:37 +01:00

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# AArch32 VFP instruction descriptions (conditional insns)
#
# Copyright (c) 2019 Linaro, Ltd
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, see <http://www.gnu.org/licenses/>.
#
# This file is processed by scripts/decodetree.py
#
# Encodings for the conditional VFP instructions are here:
# generally anything matching A32
# cccc 11.. .... .... .... 101. .... ....
# and T32
# 1110 110. .... .... .... 101. .... ....
# 1110 1110 .... .... .... 101. .... ....
# (but those patterns might also cover some Neon instructions,
# which do not live in this file.)
# VFP registers have an odd encoding with a four-bit field
# and a one-bit field which are assembled in different orders
# depending on whether the register is double or single precision.
# Each individual instruction function must do the checks for
# "double register selected but CPU does not have double support"
# and "double register number has bit 4 set but CPU does not
# support D16-D31" (which should UNDEF).
%vm_dp 5:1 0:4
%vm_sp 0:4 5:1
%vn_dp 7:1 16:4
%vn_sp 16:4 7:1
%vd_dp 22:1 12:4
%vd_sp 12:4 22:1
%vmov_idx_b 21:1 5:2
%vmov_idx_h 21:1 6:1
%vmov_imm 16:4 0:4
@vfp_dnm_s ................................ vm=%vm_sp vn=%vn_sp vd=%vd_sp
@vfp_dnm_d ................................ vm=%vm_dp vn=%vn_dp vd=%vd_dp
@vfp_dm_ss ................................ vm=%vm_sp vd=%vd_sp
@vfp_dm_dd ................................ vm=%vm_dp vd=%vd_dp
@vfp_dm_ds ................................ vm=%vm_sp vd=%vd_dp
@vfp_dm_sd ................................ vm=%vm_dp vd=%vd_sp
# VMOV scalar to general-purpose register; note that this does
# include some Neon cases.
VMOV_to_gp ---- 1110 u:1 1. 1 .... rt:4 1011 ... 1 0000 \
vn=%vn_dp size=0 index=%vmov_idx_b
VMOV_to_gp ---- 1110 u:1 0. 1 .... rt:4 1011 ..1 1 0000 \
vn=%vn_dp size=1 index=%vmov_idx_h
VMOV_to_gp ---- 1110 0 0 index:1 1 .... rt:4 1011 .00 1 0000 \
vn=%vn_dp size=2 u=0
VMOV_from_gp ---- 1110 0 1. 0 .... rt:4 1011 ... 1 0000 \
vn=%vn_dp size=0 index=%vmov_idx_b
VMOV_from_gp ---- 1110 0 0. 0 .... rt:4 1011 ..1 1 0000 \
vn=%vn_dp size=1 index=%vmov_idx_h
VMOV_from_gp ---- 1110 0 0 index:1 0 .... rt:4 1011 .00 1 0000 \
vn=%vn_dp size=2
VDUP ---- 1110 1 b:1 q:1 0 .... rt:4 1011 . 0 e:1 1 0000 \
vn=%vn_dp
VMSR_VMRS ---- 1110 111 l:1 reg:4 rt:4 1010 0001 0000
VMOV_half ---- 1110 000 l:1 .... rt:4 1001 . 001 0000 vn=%vn_sp
VMOV_single ---- 1110 000 l:1 .... rt:4 1010 . 001 0000 vn=%vn_sp
VMOV_64_sp ---- 1100 010 op:1 rt2:4 rt:4 1010 00.1 .... vm=%vm_sp
VMOV_64_dp ---- 1100 010 op:1 rt2:4 rt:4 1011 00.1 .... vm=%vm_dp
VLDR_VSTR_hp ---- 1101 u:1 .0 l:1 rn:4 .... 1001 imm:8 vd=%vd_sp
VLDR_VSTR_sp ---- 1101 u:1 .0 l:1 rn:4 .... 1010 imm:8 vd=%vd_sp
VLDR_VSTR_dp ---- 1101 u:1 .0 l:1 rn:4 .... 1011 imm:8 vd=%vd_dp
# We split the load/store multiple up into two patterns to avoid
# overlap with other insns in the "Advanced SIMD load/store and 64-bit move"
# grouping:
# P=0 U=0 W=0 is 64-bit VMOV
# P=1 W=0 is VLDR/VSTR
# P=U W=1 is UNDEF
# leaving P=0 U=1 W=x and P=1 U=0 W=1 for load/store multiple.
# These include FSTM/FLDM.
VLDM_VSTM_sp ---- 1100 1 . w:1 l:1 rn:4 .... 1010 imm:8 \
vd=%vd_sp p=0 u=1
VLDM_VSTM_dp ---- 1100 1 . w:1 l:1 rn:4 .... 1011 imm:8 \
vd=%vd_dp p=0 u=1
VLDM_VSTM_sp ---- 1101 0.1 l:1 rn:4 .... 1010 imm:8 \
vd=%vd_sp p=1 u=0 w=1
VLDM_VSTM_dp ---- 1101 0.1 l:1 rn:4 .... 1011 imm:8 \
vd=%vd_dp p=1 u=0 w=1
# 3-register VFP data-processing; bits [23,21:20,6] identify the operation.
VMLA_hp ---- 1110 0.00 .... .... 1001 .0.0 .... @vfp_dnm_s
VMLA_sp ---- 1110 0.00 .... .... 1010 .0.0 .... @vfp_dnm_s
VMLA_dp ---- 1110 0.00 .... .... 1011 .0.0 .... @vfp_dnm_d
VMLS_hp ---- 1110 0.00 .... .... 1001 .1.0 .... @vfp_dnm_s
VMLS_sp ---- 1110 0.00 .... .... 1010 .1.0 .... @vfp_dnm_s
VMLS_dp ---- 1110 0.00 .... .... 1011 .1.0 .... @vfp_dnm_d
VNMLS_hp ---- 1110 0.01 .... .... 1001 .0.0 .... @vfp_dnm_s
VNMLS_sp ---- 1110 0.01 .... .... 1010 .0.0 .... @vfp_dnm_s
VNMLS_dp ---- 1110 0.01 .... .... 1011 .0.0 .... @vfp_dnm_d
VNMLA_hp ---- 1110 0.01 .... .... 1001 .1.0 .... @vfp_dnm_s
VNMLA_sp ---- 1110 0.01 .... .... 1010 .1.0 .... @vfp_dnm_s
VNMLA_dp ---- 1110 0.01 .... .... 1011 .1.0 .... @vfp_dnm_d
VMUL_hp ---- 1110 0.10 .... .... 1001 .0.0 .... @vfp_dnm_s
VMUL_sp ---- 1110 0.10 .... .... 1010 .0.0 .... @vfp_dnm_s
VMUL_dp ---- 1110 0.10 .... .... 1011 .0.0 .... @vfp_dnm_d
VNMUL_hp ---- 1110 0.10 .... .... 1001 .1.0 .... @vfp_dnm_s
VNMUL_sp ---- 1110 0.10 .... .... 1010 .1.0 .... @vfp_dnm_s
VNMUL_dp ---- 1110 0.10 .... .... 1011 .1.0 .... @vfp_dnm_d
VADD_hp ---- 1110 0.11 .... .... 1001 .0.0 .... @vfp_dnm_s
VADD_sp ---- 1110 0.11 .... .... 1010 .0.0 .... @vfp_dnm_s
VADD_dp ---- 1110 0.11 .... .... 1011 .0.0 .... @vfp_dnm_d
VSUB_hp ---- 1110 0.11 .... .... 1001 .1.0 .... @vfp_dnm_s
VSUB_sp ---- 1110 0.11 .... .... 1010 .1.0 .... @vfp_dnm_s
VSUB_dp ---- 1110 0.11 .... .... 1011 .1.0 .... @vfp_dnm_d
VDIV_hp ---- 1110 1.00 .... .... 1001 .0.0 .... @vfp_dnm_s
VDIV_sp ---- 1110 1.00 .... .... 1010 .0.0 .... @vfp_dnm_s
VDIV_dp ---- 1110 1.00 .... .... 1011 .0.0 .... @vfp_dnm_d
VFMA_hp ---- 1110 1.10 .... .... 1001 .0. 0 .... @vfp_dnm_s
VFMS_hp ---- 1110 1.10 .... .... 1001 .1. 0 .... @vfp_dnm_s
VFNMS_hp ---- 1110 1.01 .... .... 1001 .0. 0 .... @vfp_dnm_s
VFNMA_hp ---- 1110 1.01 .... .... 1001 .1. 0 .... @vfp_dnm_s
VFMA_sp ---- 1110 1.10 .... .... 1010 .0. 0 .... @vfp_dnm_s
VFMS_sp ---- 1110 1.10 .... .... 1010 .1. 0 .... @vfp_dnm_s
VFNMS_sp ---- 1110 1.01 .... .... 1010 .0. 0 .... @vfp_dnm_s
VFNMA_sp ---- 1110 1.01 .... .... 1010 .1. 0 .... @vfp_dnm_s
VFMA_dp ---- 1110 1.10 .... .... 1011 .0.0 .... @vfp_dnm_d
VFMS_dp ---- 1110 1.10 .... .... 1011 .1.0 .... @vfp_dnm_d
VFNMS_dp ---- 1110 1.01 .... .... 1011 .0.0 .... @vfp_dnm_d
VFNMA_dp ---- 1110 1.01 .... .... 1011 .1.0 .... @vfp_dnm_d
VMOV_imm_hp ---- 1110 1.11 .... .... 1001 0000 .... \
vd=%vd_sp imm=%vmov_imm
VMOV_imm_sp ---- 1110 1.11 .... .... 1010 0000 .... \
vd=%vd_sp imm=%vmov_imm
VMOV_imm_dp ---- 1110 1.11 .... .... 1011 0000 .... \
vd=%vd_dp imm=%vmov_imm
VMOV_reg_sp ---- 1110 1.11 0000 .... 1010 01.0 .... @vfp_dm_ss
VMOV_reg_dp ---- 1110 1.11 0000 .... 1011 01.0 .... @vfp_dm_dd
VABS_hp ---- 1110 1.11 0000 .... 1001 11.0 .... @vfp_dm_ss
VABS_sp ---- 1110 1.11 0000 .... 1010 11.0 .... @vfp_dm_ss
VABS_dp ---- 1110 1.11 0000 .... 1011 11.0 .... @vfp_dm_dd
VNEG_hp ---- 1110 1.11 0001 .... 1001 01.0 .... @vfp_dm_ss
VNEG_sp ---- 1110 1.11 0001 .... 1010 01.0 .... @vfp_dm_ss
VNEG_dp ---- 1110 1.11 0001 .... 1011 01.0 .... @vfp_dm_dd
VSQRT_hp ---- 1110 1.11 0001 .... 1001 11.0 .... @vfp_dm_ss
VSQRT_sp ---- 1110 1.11 0001 .... 1010 11.0 .... @vfp_dm_ss
VSQRT_dp ---- 1110 1.11 0001 .... 1011 11.0 .... @vfp_dm_dd
VCMP_hp ---- 1110 1.11 010 z:1 .... 1001 e:1 1.0 .... \
vd=%vd_sp vm=%vm_sp
VCMP_sp ---- 1110 1.11 010 z:1 .... 1010 e:1 1.0 .... \
vd=%vd_sp vm=%vm_sp
VCMP_dp ---- 1110 1.11 010 z:1 .... 1011 e:1 1.0 .... \
vd=%vd_dp vm=%vm_dp
# VCVTT and VCVTB from f16: Vd format depends on size bit; Vm is always vm_sp
VCVT_f32_f16 ---- 1110 1.11 0010 .... 1010 t:1 1.0 .... \
vd=%vd_sp vm=%vm_sp
VCVT_f64_f16 ---- 1110 1.11 0010 .... 1011 t:1 1.0 .... \
vd=%vd_dp vm=%vm_sp
# VCVTB and VCVTT to f16: Vd format is always vd_sp;
# Vm format depends on size bit
VCVT_b16_f32 ---- 1110 1.11 0011 .... 1001 t:1 1.0 .... \
vd=%vd_sp vm=%vm_sp
VCVT_f16_f32 ---- 1110 1.11 0011 .... 1010 t:1 1.0 .... \
vd=%vd_sp vm=%vm_sp
VCVT_f16_f64 ---- 1110 1.11 0011 .... 1011 t:1 1.0 .... \
vd=%vd_sp vm=%vm_dp
VRINTR_hp ---- 1110 1.11 0110 .... 1001 01.0 .... @vfp_dm_ss
VRINTR_sp ---- 1110 1.11 0110 .... 1010 01.0 .... @vfp_dm_ss
VRINTR_dp ---- 1110 1.11 0110 .... 1011 01.0 .... @vfp_dm_dd
VRINTZ_hp ---- 1110 1.11 0110 .... 1001 11.0 .... @vfp_dm_ss
VRINTZ_sp ---- 1110 1.11 0110 .... 1010 11.0 .... @vfp_dm_ss
VRINTZ_dp ---- 1110 1.11 0110 .... 1011 11.0 .... @vfp_dm_dd
VRINTX_hp ---- 1110 1.11 0111 .... 1001 01.0 .... @vfp_dm_ss
VRINTX_sp ---- 1110 1.11 0111 .... 1010 01.0 .... @vfp_dm_ss
VRINTX_dp ---- 1110 1.11 0111 .... 1011 01.0 .... @vfp_dm_dd
# VCVT between single and double:
# Vm precision depends on size; Vd is its reverse
VCVT_sp ---- 1110 1.11 0111 .... 1010 11.0 .... @vfp_dm_ds
VCVT_dp ---- 1110 1.11 0111 .... 1011 11.0 .... @vfp_dm_sd
# VCVT from integer to floating point: Vm always single; Vd depends on size
VCVT_int_hp ---- 1110 1.11 1000 .... 1001 s:1 1.0 .... \
vd=%vd_sp vm=%vm_sp
VCVT_int_sp ---- 1110 1.11 1000 .... 1010 s:1 1.0 .... \
vd=%vd_sp vm=%vm_sp
VCVT_int_dp ---- 1110 1.11 1000 .... 1011 s:1 1.0 .... \
vd=%vd_dp vm=%vm_sp
# VJCVT is always dp to sp
VJCVT ---- 1110 1.11 1001 .... 1011 11.0 .... @vfp_dm_sd
# VCVT between floating-point and fixed-point. The immediate value
# is in the same format as a Vm single-precision register number.
# We assemble bits 18 (op), 16 (u) and 7 (sx) into a single opc field
# for the convenience of the trans_VCVT_fix functions.
%vcvt_fix_op 18:1 16:1 7:1
VCVT_fix_hp ---- 1110 1.11 1.1. .... 1001 .1.0 .... \
vd=%vd_sp imm=%vm_sp opc=%vcvt_fix_op
VCVT_fix_sp ---- 1110 1.11 1.1. .... 1010 .1.0 .... \
vd=%vd_sp imm=%vm_sp opc=%vcvt_fix_op
VCVT_fix_dp ---- 1110 1.11 1.1. .... 1011 .1.0 .... \
vd=%vd_dp imm=%vm_sp opc=%vcvt_fix_op
# VCVT float to integer (VCVT and VCVTR): Vd always single; Vd depends on size
VCVT_hp_int ---- 1110 1.11 110 s:1 .... 1001 rz:1 1.0 .... \
vd=%vd_sp vm=%vm_sp
VCVT_sp_int ---- 1110 1.11 110 s:1 .... 1010 rz:1 1.0 .... \
vd=%vd_sp vm=%vm_sp
VCVT_dp_int ---- 1110 1.11 110 s:1 .... 1011 rz:1 1.0 .... \
vd=%vd_sp vm=%vm_dp
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