RISC-V VAESDF.VV Instruction Details

Instruction ManualR-type

Vector AES final-round decryption: transform 128-bit state groups in vd with corresponding round-key groups from vs2.

Instruction Syntax

vaesdf.vv vd, vs2

Operand Breakdown

Destination rd: register receiving the operation result.

Source rs1: register holding the first operand.

Source rs2: register holding the second operand.

ZvknedVector CryptoAES

Related Search Terms

vaesdf.vv instruction RISC-V vaesdf.vv vaesdf.vv syntax vaesdf.vv encoding Zvkned vector AES final-round decryption

Instruction Behavior

vaesdf.vv performs AES final-round decryption. Each 128-bit element group in vd is transformed using InvSubBytes+InvShiftRows and XORed with the corresponding 128-bit round-key element group from vs2; the new state is written back to vd. SEW must be 32.

Quick Understanding & Search Notes

VAESDF.VV is a Zvkned vector instruction for vector AES final-round decryption. This page is checked against the official vector crypto extension and V-extension execution model.

Performs AES final-round decryption: InvShiftRows and InvSubBytes followed by XOR with the round key; SEW must be 32 and the element group is 128 bits.

This element-group crypto instruction has no vm mask operand and executes at element-group granularity.

SEW=32, EGW=128, EGS=4; vl and vstart must be multiples of 4, and LMUL*VLEN must hold at least one element group.

RISC-V Unprivileged ISA Manual: Vector cryptography extensions 1.0 RISC-V Unprivileged ISA Manual: V standard vector extension

Common Usage Scenarios

Crypto & Security

Understand this scenario with real code like «vaesdf.vv vd, vs2».

Vector Acceleration

Understand this scenario with real code like «vaesdf.vv vd, vs2».

Pre-Use Checklist

Syntax Check

Confirm the current instruction format is R-type.
Confirm the operand order matches the example.

Semantic Check

Ensure the destination register usage is compatible with the calling convention.
Confirm this is not the lower-level form of a pseudo-instruction expansion.

Pitfalls / Common Confusions

No vm operand; this element-group crypto instruction is not maskable.

SEW must be 32 and each element group is 128 bits.

vd is both input state and destination.

SEW=32, EGW=128, EGS=4; vl and vstart must be multiples of 4, and LMUL*VLEN must cover at least one 128-bit element group.

FAQ

Can VAESDF.VV always use a v0.t mask?

No. This element-group crypto instruction has no vm operand; ordinary RVV mask syntax should not be added to examples.

What determines the element width for VAESDF.VV?

This instruction fixes SEW=32 and executes on 128-bit element groups; other SEW values are reserved/illegal cases.