[PATCH 1/1] AArch64: Add FEAT_F16F32DOT instructions

Saurabh Jha saurabh.jha@arm.com
Thu Oct 23 14:16:32 GMT 2025



On 10/23/2025 3:05 PM, Sivan Shani wrote:
>      This includes the instructions for the F16F32DOT feature:
>      - FDOT half-precision to single-precision, by element
>      - FDOT half-precision to single-precision, vector

The code looks good to me but you can add more description in your 
commit message. Specifically, you can add that you added a feature flag 
and two new operands.

Thanks,
Saurabh


> ---
>   gas/config/tc-aarch64.c                    |  1 +
>   gas/doc/c-aarch64.texi                     |  2 ++
>   gas/testsuite/gas/aarch64/f16f32dot-simd.d | 24 +++++++++++++
>   gas/testsuite/gas/aarch64/f16f32dot-simd.s | 19 ++++++++++
>   include/opcode/aarch64.h                   |  2 ++
>   opcodes/aarch64-dis-2.c                    | 42 ++++++++++++++++------
>   opcodes/aarch64-tbl-2.h                    |  2 ++
>   opcodes/aarch64-tbl.h                      |  8 +++++
>   8 files changed, 89 insertions(+), 11 deletions(-)
>   create mode 100644 gas/testsuite/gas/aarch64/f16f32dot-simd.d
>   create mode 100644 gas/testsuite/gas/aarch64/f16f32dot-simd.s
> 
> diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
> index 0ca54c3bd40..e9188a883d3 100644
> --- a/gas/config/tc-aarch64.c
> +++ b/gas/config/tc-aarch64.c
> @@ -10905,6 +10905,7 @@ static const struct aarch64_option_cpu_value_table aarch64_features[] = {
>     {"ssve-fexpa",	AARCH64_FEATURE (SSVE_FEXPA), AARCH64_FEATURE (SME2)},
>     {"sme-tmop",		AARCH64_FEATURE (SME_TMOP), AARCH64_FEATURE (SME2)},
>     {"sme-mop4",		AARCH64_FEATURE (SME_MOP4), AARCH64_FEATURE (SME2)},
> +  {"f16f32dot",		AARCH64_FEATURE (F16F32DOT), AARCH64_FEATURE (SIMD)},
>     {NULL,		AARCH64_NO_FEATURES, AARCH64_NO_FEATURES},
>   };
>   
> diff --git a/gas/doc/c-aarch64.texi b/gas/doc/c-aarch64.texi
> index 9683d411ce9..4a541ce9fad 100644
> --- a/gas/doc/c-aarch64.texi
> +++ b/gas/doc/c-aarch64.texi
> @@ -219,6 +219,8 @@ automatically cause those extensions to be disabled.
>    @tab Enable Armv8.2 16-bit floating-point multiplication variant support.
>   @item @code{fp16} @tab @code{fp}
>    @tab Enable Armv8.2 16-bit floating-point support.
> +@item @code{f16f32dot} @tab @code{simd}
> + @tab Enable Armv9.7 f16f32dot instructions.
>   @item @code{fprcvt} @tab @code{fp}
>    @tab Enable Armv9.6 fprcvt instructions.
>   @item @code{frintts} @tab @code{fp}
> diff --git a/gas/testsuite/gas/aarch64/f16f32dot-simd.d b/gas/testsuite/gas/aarch64/f16f32dot-simd.d
> new file mode 100644
> index 00000000000..53b00f95b7b
> --- /dev/null
> +++ b/gas/testsuite/gas/aarch64/f16f32dot-simd.d
> @@ -0,0 +1,24 @@
> +#as: -march=armv8-a+f16f32dot
> +#objdump: -dr
> +
> +.*:     file format .*
> +
> +Disassembly of section \.text:
> +
> +0+ <\.text>:
> + *[0-9a-f]+:[ \t]+0f409000[ \t]+fdot[ \t]+v0\.2s, v0\.4h, v0\.2h\[0\]
> + *[0-9a-f]+:[ \t]+0f60901f[ \t]+fdot[ \t]+v31\.2s, v0\.4h, v0\.2h\[1\]
> + *[0-9a-f]+:[ \t]+0f409be0[ \t]+fdot[ \t]+v0\.2s, v31\.4h, v0\.2h\[2\]
> + *[0-9a-f]+:[ \t]+0f7f9800[ \t]+fdot[ \t]+v0\.2s, v0\.4h, v31\.2h\[3\]
> + *[0-9a-f]+:[ \t]+4f409000[ \t]+fdot[ \t]+v0\.4s, v0\.8h, v0\.2h\[0\]
> + *[0-9a-f]+:[ \t]+4f60901f[ \t]+fdot[ \t]+v31\.4s, v0\.8h, v0\.2h\[1\]
> + *[0-9a-f]+:[ \t]+4f409be0[ \t]+fdot[ \t]+v0\.4s, v31\.8h, v0\.2h\[2\]
> + *[0-9a-f]+:[ \t]+4f7f9800[ \t]+fdot[ \t]+v0\.4s, v0\.8h, v31\.2h\[3\]
> + *[0-9a-f]+:[ \t]+0e80fc00[ \t]+fdot[ \t]+v0\.2s, v0\.4h, v0\.4h
> + *[0-9a-f]+:[ \t]+0e80fc1f[ \t]+fdot[ \t]+v31\.2s, v0\.4h, v0\.4h
> + *[0-9a-f]+:[ \t]+0e80ffe0[ \t]+fdot[ \t]+v0\.2s, v31\.4h, v0\.4h
> + *[0-9a-f]+:[ \t]+0e9ffc00[ \t]+fdot[ \t]+v0\.2s, v0\.4h, v31\.4h
> + *[0-9a-f]+:[ \t]+4e80fc00[ \t]+fdot[ \t]+v0\.4s, v0\.8h, v0\.8h
> + *[0-9a-f]+:[ \t]+4e80fc1f[ \t]+fdot[ \t]+v31\.4s, v0\.8h, v0\.8h
> + *[0-9a-f]+:[ \t]+4e80ffe0[ \t]+fdot[ \t]+v0\.4s, v31\.8h, v0\.8h
> + *[0-9a-f]+:[ \t]+4e9ffc00[ \t]+fdot[ \t]+v0\.4s, v0\.8h, v31\.8h
> diff --git a/gas/testsuite/gas/aarch64/f16f32dot-simd.s b/gas/testsuite/gas/aarch64/f16f32dot-simd.s
> new file mode 100644
> index 00000000000..ff9203307b6
> --- /dev/null
> +++ b/gas/testsuite/gas/aarch64/f16f32dot-simd.s
> @@ -0,0 +1,19 @@
> +fdot v0.2s, v0.4h, v0.2h[0]
> +fdot v31.2s, v0.4h, v0.2h[1]
> +fdot v0.2s, v31.4h, v0.2h[2]
> +fdot v0.2s, v0.4h, v31.2h[3]
> +
> +fdot v0.4s, v0.8h, v0.2h[0]
> +fdot v31.4s, v0.8h, v0.2h[1]
> +fdot v0.4s, v31.8h, v0.2h[2]
> +fdot v0.4s, v0.8h, v31.2h[3]
> +
> +fdot v0.2s, v0.4h, v0.4h
> +fdot v31.2s, v0.4h, v0.4h
> +fdot v0.2s, v31.4h, v0.4h
> +fdot v0.2s, v0.4h, v31.4h
> +
> +fdot v0.4s, v0.8h, v0.8h
> +fdot v31.4s, v0.8h, v0.8h
> +fdot v0.4s, v31.8h, v0.8h
> +fdot v0.4s, v0.8h, v31.8h
> diff --git a/include/opcode/aarch64.h b/include/opcode/aarch64.h
> index e65b61c3f9c..3344db2a705 100644
> --- a/include/opcode/aarch64.h
> +++ b/include/opcode/aarch64.h
> @@ -263,6 +263,8 @@ enum aarch64_feature_bit {
>     AARCH64_FEATURE_SME_TMOP,
>     /* SME MOP4 instructions.  */
>     AARCH64_FEATURE_SME_MOP4,
> +  /* F16F32DOT instructions.  */
> +  AARCH64_FEATURE_F16F32DOT,
>   
>     /* Virtual features.  These are used to gate instructions that are enabled
>        by either of two (or more) sets of command line flags.  */
> diff --git a/opcodes/aarch64-dis-2.c b/opcodes/aarch64-dis-2.c
> index ecaea2d2fdb..5c613c618da 100644
> --- a/opcodes/aarch64-dis-2.c
> +++ b/opcodes/aarch64-dis-2.c
> @@ -28611,10 +28611,20 @@ aarch64_opcode_lookup_1 (uint32_t word)
>                                                       {
>                                                         if (((word >> 22) & 0x1) == 0)
>                                                           {
> -                                                          /* 33222222222211111111110000000000
> -                                                             10987654321098765432109876543210
> -                                                             0x001110x00xxxxxx11111xxxxxxxxxx.  */
> -                                                          return A64_OPID_0e00fc00_fdot_Vd_Vn_Vm;
> +                                                          if (((word >> 23) & 0x1) == 0)
> +                                                            {
> +                                                              /* 33222222222211111111110000000000
> +                                                                 10987654321098765432109876543210
> +                                                                 0x001110000xxxxxx11111xxxxxxxxxx.  */
> +                                                              return A64_OPID_0e00fc00_fdot_Vd_Vn_Vm;
> +                                                            }
> +                                                          else
> +                                                            {
> +                                                              /* 33222222222211111111110000000000
> +                                                                 10987654321098765432109876543210
> +                                                                 0x001110100xxxxxx11111xxxxxxxxxx.  */
> +                                                              return A64_OPID_0e80fc00_fdot_Vd_Vn_Vm;
> +                                                            }
>                                                           }
>                                                         else
>                                                           {
> @@ -34411,19 +34421,29 @@ aarch64_opcode_lookup_1 (uint32_t word)
>                                           {
>                                             if (((word >> 23) & 0x1) == 0)
>                                               {
> -                                              if (((word >> 29) & 0x1) == 0)
> +                                              if (((word >> 22) & 0x1) == 0)
>                                                   {
> -                                                  /* 33222222222211111111110000000000
> -                                                     10987654321098765432109876543210
> -                                                     xx0011110xxxxxxx1001x0xxxxxxxxxx.  */
> -                                                  return A64_OPID_0f009000_fmul_Vd_Vn_Em16;
> +                                                  if (((word >> 29) & 0x1) == 0)
> +                                                    {
> +                                                      /* 33222222222211111111110000000000
> +                                                         10987654321098765432109876543210
> +                                                         xx00111100xxxxxx1001x0xxxxxxxxxx.  */
> +                                                      return A64_OPID_0f009000_fmul_Vd_Vn_Em16;
> +                                                    }
> +                                                  else
> +                                                    {
> +                                                      /* 33222222222211111111110000000000
> +                                                         10987654321098765432109876543210
> +                                                         xx10111100xxxxxx1001x0xxxxxxxxxx.  */
> +                                                      return A64_OPID_2f009000_fmulx_Vd_Vn_Em16;
> +                                                    }
>                                                   }
>                                                 else
>                                                   {
>                                                     /* 33222222222211111111110000000000
>                                                        10987654321098765432109876543210
> -                                                     xx1011110xxxxxxx1001x0xxxxxxxxxx.  */
> -                                                  return A64_OPID_2f009000_fmulx_Vd_Vn_Em16;
> +                                                     xxx0111101xxxxxx1001x0xxxxxxxxxx.  */
> +                                                  return A64_OPID_0f409000_fdot_Vd_Vn_Em16;
>                                                   }
>                                               }
>                                             else
> diff --git a/opcodes/aarch64-tbl-2.h b/opcodes/aarch64-tbl-2.h
> index 1263f1f9bd8..1e7ad140145 100644
> --- a/opcodes/aarch64-tbl-2.h
> +++ b/opcodes/aarch64-tbl-2.h
> @@ -3995,5 +3995,7 @@ enum aarch64_opcode_idx
>     A64_OPID_a1c00018_usmop4s_SME_ZAda_3b_SME_Zn_6_3_SME_Zm_17_3,
>     A64_OPID_a1c00218_usmop4s_SME_ZAda_3b_SME_Znx2_6_3_SME_Zm_17_3,
>     A64_OPID_a1d00218_usmop4s_SME_ZAda_3b_SME_Znx2_6_3_SME_Zmx2_17_3,
> +  A64_OPID_0f409000_fdot_Vd_Vn_Em16,
> +  A64_OPID_0e80fc00_fdot_Vd_Vn_Vm,
>     A64_OPID_MAX,
>   };
> diff --git a/opcodes/aarch64-tbl.h b/opcodes/aarch64-tbl.h
> index e7b17061d82..13b5a3b48df 100644
> --- a/opcodes/aarch64-tbl.h
> +++ b/opcodes/aarch64-tbl.h
> @@ -3057,6 +3057,8 @@ static const aarch64_feature_set aarch64_feature_sme_mop4_f8f32 =
>     AARCH64_FEATURES (2, SME_MOP4, SME_F8F32);
>   static const aarch64_feature_set aarch64_feature_sme_mop4_i16i64 =
>     AARCH64_FEATURES (2, SME_MOP4, SME_I16I64);
> +static const aarch64_feature_set aarch64_feature_f16f32dot =
> +  AARCH64_FEATURE (F16F32DOT);
>   
>   #define CORE		&aarch64_feature_v8
>   #define FP		&aarch64_feature_fp
> @@ -3181,6 +3183,7 @@ static const aarch64_feature_set aarch64_feature_sme_mop4_i16i64 =
>   #define SME_MOP4_F8F16	&aarch64_feature_sme_mop4_f8f16
>   #define SME_MOP4_F8F32	&aarch64_feature_sme_mop4_f8f32
>   #define SME_MOP4_I16I64	&aarch64_feature_sme_mop4_i16i64
> +#define F16F32DOT	&aarch64_feature_f16f32dot
>   
>   #define CORE_INSN(NAME,OPCODE,MASK,CLASS,OP,OPS,QUALS,FLAGS) \
>     { NAME, OPCODE, MASK, CLASS, OP, CORE, OPS, QUALS, FLAGS | F_INVALID_IMM_SYMS_1, 0, 0, NULL }
> @@ -3510,6 +3513,8 @@ static const aarch64_feature_set aarch64_feature_sme_mop4_i16i64 =
>   #define SME_MOP4_I16I64_INSN(NAME,OPCODE,MASK,CLASS,OPS,QUALS,FLAGS,TIED) \
>     { NAME, OPCODE, MASK, CLASS, 0, SME_MOP4_I16I64, OPS, QUALS, \
>       FLAGS | F_STRICT, 0, TIED, NULL }
> +#define F16F32DOT_INSN(NAME,OPCODE,MASK,CLASS,OPS,QUALS,FLAGS) \
> +  { NAME, OPCODE, MASK, CLASS, 0, F16F32DOT, OPS, QUALS, FLAGS, 0, 0, NULL }
>   
>   #define MOPS_CPY_OP1_OP2_PME_INSN(NAME, OPCODE, MASK, FLAGS, CONSTRAINTS) \
>     MOPS_INSN (NAME, OPCODE, MASK, 0, \
> @@ -7737,6 +7742,9 @@ const struct aarch64_opcode aarch64_opcode_table[] =
>     SME_MOP4_I16I64_INSN ("usmop4s", 0xa1c00018, 0xfff1fe38, sme_misc, OP3 (SME_ZAda_3b, SME_Zn_6_3, SME_Zm_17_3), OP_SVE_DHH, 0, 0),
>     SME_MOP4_I16I64_INSN ("usmop4s", 0xa1c00218, 0xfff1fe38, sme_misc, OP3 (SME_ZAda_3b, SME_Znx2_6_3, SME_Zm_17_3), OP_SVE_DHH, 0, 0),
>     SME_MOP4_I16I64_INSN ("usmop4s", 0xa1d00218, 0xfff1fe38, sme_misc, OP3 (SME_ZAda_3b, SME_Znx2_6_3, SME_Zmx2_17_3), OP_SVE_DHH, 0, 0),
> +  /* F16F32DOT instructions.  */
> +  F16F32DOT_INSN ("fdot", 0x0f409000, 0xbfc0f400, dotproduct, OP3 (Vd, Vn, Em16), QL_BFDOT64I, F_SIZEQ),
> +  F16F32DOT_INSN ("fdot", 0x0e80fc00, 0xbfe0fc00, dotproduct, OP3 (Vd, Vn, Vm), QL_BFDOT64, F_SIZEQ),
>   
>     {0, 0, 0, 0, 0, 0, {}, {}, 0, 0, 0, NULL},
>   };



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