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AMDGPU Instructions Notation

Introduction

This is an overview of notation used to describe the syntax of AMDGPU assembler instructions.

This notation mimics the :ref:`syntax of assembler instructions<amdgpu_syn_instructions>` except that instead of real operands and modifiers it provides references to their description.

Operands

An instruction may have zero or more operands. They are comma-separated in the description:

<:ref:`description of operand 0<amdgpu_syn_instruction_operand_notation>`>, <:ref:`description of operand 1<amdgpu_syn_instruction_operand_notation>`>, ...

The order of operands is fixed. Operands cannot be omitted except for special cases described below.

Notation

An operand is described using the following notation:

<name><tag0><tag1>...

Where:

  • name is a link to a description of the operand.
  • tags are optional. They are used to indicate special operand properties:
Operand tag Meaning
:opt An optional operand.
:m An operand which may be used with :ref:`VOP3 operand modifiers<amdgpu_synid_vop3_operand_modifiers>` or :ref:`SDWA operand modifiers<amdgpu_synid_sdwa_operand_modifiers>`.
:dst An input operand which may also serve as a destination if :ref:`glc<amdgpu_synid_glc>` modifier is specified.
:fx This is an f32 or f16 operand depending on :ref:`m_op_sel_hi<amdgpu_synid_mad_mix_op_sel_hi>` modifier.
:<type> Operand type differs from type :ref:`implied by the opcode name<amdgpu_syn_instruction_type>`. This tag specifies actual operand type.

Examples:

src1:m             // src1 operand may be used with operand modifiers
vdata:dst          // vdata operand may be used as both source and destination
vdst:u32           // vdst operand has u32 type

Modifiers

An instruction may have zero or more optional modifiers. They are space-separated in the description:

<:ref:`description of modifier 0<amdgpu_syn_instruction_modifier_notation>`> <:ref:`description of modifier 1<amdgpu_syn_instruction_modifier_notation>`> ...

The order of modifiers is fixed.

Notation

A modifier is described using the following notation:

<name>

Where name is a link to a description of the modifier.