[PATCH 1/2] RISC-V: Add Zvdota extension classes

[Jeffrey Law]

On 6/29/2026 9:34 PM, Jiawei wrote:
> This patch adds assembler/disassembler support for the RISC-V Zvdota family of extensions [1], which compute a dot product between two vector register groups.
>
> The Zvdota extension family includes the following extensions:
>
> Zvqwdota8i: dot product of 8-bit integers with 32-bit accumulation.
> Zvqwdota16i: dot product of 16-bit integers with 64-bit accumulation.
> Zvfwdota16bf: dot product of bfloat16 floating-point numbers with 32-bit accumulation.
> Zvfqwdota8f: dot product of 8-bit floating-point numbers with 32-bit accumulation.
>
> Zvdota also uses the vtype alternative format bit, altfmt, which is bit 8 of the vtype CSR. This patch adds symbolic e8alt and e16alt vsew constants for vsetvli/vsetivli so that assembly code can select the alternative element formats required by these dot-product instructions.
>
> [1] https://github.com/riscv/riscv-isa-manual/blob/zvbdot/src/zvdota.adoc
>
> bfd/ChangeLog:
>
> 	* elfxx-riscv.c (riscv_implicit_subsets): New implies.
> 	(riscv_supported_std_z_ext): New extensions.
> 	(riscv_multi_subset_supports): Ditto.
> 	(riscv_multi_subset_supports_ext): Ditto.
>
> gas/ChangeLog:
>
> 	* NEWS: Add zvqwdota8i, zvqwdota16i, zvfwdota16bf and
> 	zvfqwdota8f extensions.
> 	* config/tc-riscv.c (riscv_vsew_altfmt): New vsew altfmt
> 	constants array for e8alt and e16alt.
> 	(riscv_vtype_altfmt_supported): New function.
> 	(my_getVsetvliExpression): Ditto.
> 	* testsuite/gas/riscv/march-help.l: New test.
> 	* testsuite/gas/riscv/vector-vtype-altfmt.d: Ditto.
> 	* testsuite/gas/riscv/vector-vtype-altfmt.s: Ditto.
> 	* testsuite/gas/riscv/zvdota.d: Ditto.
> 	* testsuite/gas/riscv/zvdota.s: Ditto.
>
> include/ChangeLog:
>
> 	* opcode/riscv-opc.h (MATCH_VQWDOTAU_VV, MASK_VQWDOTAU_VV): New encoding.
> 	(MATCH_VQWDOTAS_VV, MASK_VQWDOTAS_VV): Ditto.
> 	(MATCH_VFWDOTA_VV, MASK_VFWDOTA_VV): Ditto.
> 	(MATCH_VFQWDOTA_VV, MASK_VFQWDOTA_VV): Ditto.
> 	(MATCH_VFQWDOTA_ALT_VV, MASK_VFQWDOTA_ALT_VV): Ditto.
> 	(DECLARE_INSN): New declarations.
> 	* opcode/riscv.h (OP_MASK_VTYPE_ALTFMT, OP_SH_VTYPE_ALTFMT): New vtype altfmt.
> 	(enum riscv_insn_class): New extension classes.
>
> opcodes/ChangeLog:
>
> 	* riscv-dis.c (print_insn_args): Add altfmt support.
> 	* riscv-opc.c (riscv_opcodes): New instructions.
THanks!  I've pushed both patches in this series to the trunk.

jeff