============================
AMDGPU Instructions Notation
============================
.. contents::
:local:
.. _amdgpu_syn_instruction_notation:
Introduction
============
This is an overview of notation used to describe the syntax of AMDGPU assembler instructions.
This notation looks a lot like the :ref:`syntax of assembler instructions<amdgpu_syn_instructions>`,
except that instead of real operands and modifiers, it uses references to their descriptions.
Instructions
============
Notation
~~~~~~~~
This is the notation used to describe AMDGPU instructions:
| ``<``\ :ref:`opcode description<amdgpu_syn_opcode_notation>`\ ``>
<``\ :ref:`operands description<amdgpu_syn_instruction_operands_notation>`\ ``>
<``\ :ref:`modifiers description<amdgpu_syn_instruction_modifiers_notation>`\ ``>``
.. _amdgpu_syn_opcode_notation:
Opcode
======
Notation
~~~~~~~~
TBD
.. _amdgpu_syn_instruction_operands_notation:
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.
.. _amdgpu_syn_instruction_operand_notation:
Notation
~~~~~~~~
An operand is described using the following notation:
*<kind><name><tag0><tag1>...*
Where:
* *kind* is an optional prefix describing operand :ref:`kind<amdgpu_syn_instruction_operand_kinds>`.
* *name* is a link to a description of the operand.
* *tags* are optional. They are used to indicate
:ref:`special operand properties<amdgpu_syn_instruction_operand_tags>`.
.. _amdgpu_syn_instruction_operand_kinds:
Operand Kinds
^^^^^^^^^^^^^
Operand kind indicates which values are accepted by the operand.
* Operands which only accept *vector* registers are labelled with 'v' prefix.
* Operands which only accept *scalar* registers and values are labelled with 's' prefix.
* Operands which accept any registers and values have no prefix.
Examples:
.. parsed-literal::
vdata // operand only accepts vector registers
sdst // operand only accepts scalar registers
src1 // operand accepts vector registers, scalar registers, and scalar values
.. _amdgpu_syn_instruction_operand_tags:
Operand Tags
^^^^^^^^^^^^
Operand tags indicate special operand properties.
============== =================================================================================
Operand tag Meaning
============== =================================================================================
:opt An optional operand.
:m An operand which may be used with operand modifiers
:ref:`abs<amdgpu_synid_abs>`, :ref:`neg<amdgpu_synid_neg>` or
:ref:`sext<amdgpu_synid_sext>`.
:dst An input operand which is also used as a destination
if :ref:`glc<amdgpu_synid_glc>` modifier is specified.
:fx This is a *f32* or *f16* operand, depending on
:ref:`m_op_sel_hi<amdgpu_synid_mad_mix_op_sel_hi>` modifier.
:<type> The operand *type* differs from the *type*
:ref:`implied by the opcode name<amdgpu_syn_instruction_type>`.
This tag specifies the actual operand *type*.
============== =================================================================================
Examples:
.. parsed-literal::
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
.. _amdgpu_syn_instruction_modifiers_notation:
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.
.. _amdgpu_syn_instruction_modifier_notation:
Notation
~~~~~~~~
A *modifier* is described using the following notation:
*<name>*
Where the *name* is a link to a description of the *modifier*.
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