llvm-mirror/docs/AMDGPUModifierSyntax.rst

======================================
Syntax of AMDGPU Instruction Modifiers
======================================

.. contents::
   :local:

Conventions
===========

The following notation is used throughout this document:

    =================== =============================================================
    Notation            Description
    =================== =============================================================
    {0..N}              Any integer value in the range from 0 to N (inclusive).
    <x>                 Syntax and meaning of *x* is explained elsewhere.
    =================== =============================================================

.. _amdgpu_syn_modifiers:

Modifiers
=========

DS Modifiers
------------

.. _amdgpu_synid_ds_offset8:

offset8
~~~~~~~

Specifies an immediate unsigned 8-bit offset, in bytes. The default value is 0.

Used with DS instructions which have 2 addresses.

    =================== =====================================================
    Syntax              Description
    =================== =====================================================
    offset:{0..0xFF}    Specifies an unsigned 8-bit offset as a positive
                        :ref:`integer number <amdgpu_synid_integer_number>`.
    =================== =====================================================

Examples:

.. parsed-literal::

  offset:255
  offset:0xff

.. _amdgpu_synid_ds_offset16:

offset16
~~~~~~~~

Specifies an immediate unsigned 16-bit offset, in bytes. The default value is 0.

Used with DS instructions which have 1 address.

    ==================== ======================================================
    Syntax               Description
    ==================== ======================================================
    offset:{0..0xFFFF}   Specifies an unsigned 16-bit offset as a positive
                         :ref:`integer number <amdgpu_synid_integer_number>`.
    ==================== ======================================================

Examples:

.. parsed-literal::

  offset:65535
  offset:0xffff

.. _amdgpu_synid_sw_offset16:

pattern
~~~~~~~

This is a special modifier which may be used with *ds_swizzle_b32* instruction only.
It specifies a swizzle pattern in numeric or symbolic form. The default value is 0.

See AMD documentation for more information.

    ======================================================= ===========================================================
    Syntax                                                  Description
    ======================================================= ===========================================================
    offset:{0..0xFFFF}                                      Specifies a 16-bit swizzle pattern.
    offset:swizzle(QUAD_PERM,{0..3},{0..3},{0..3},{0..3})   Specifies a quad permute mode pattern

                                                            Each number is a lane *id*.
    offset:swizzle(BITMASK_PERM, "<mask>")                  Specifies a bitmask permute mode pattern.

                                                            The pattern converts a 5-bit lane *id* to another
                                                            lane *id* with which the lane interacts.

                                                            *mask* is a 5 character sequence which
                                                            specifies how to transform the bits of the
                                                            lane *id*. 

                                                            The following characters are allowed:

                                                            * "0" - set bit to 0.

                                                            * "1" - set bit to 1.

                                                            * "p" - preserve bit.

                                                            * "i" - inverse bit.

    offset:swizzle(BROADCAST,{2..32},{0..N})                Specifies a broadcast mode.

                                                            Broadcasts the value of any particular lane to
                                                            all lanes in its group.

                                                            The first numeric parameter is a group
                                                            size and must be equal to 2, 4, 8, 16 or 32.

                                                            The second numeric parameter is an index of the
                                                            lane being broadcasted. 

                                                            The index must not exceed group size.
    offset:swizzle(SWAP,{1..16})                            Specifies a swap mode.

                                                            Swaps the neighboring groups of
                                                            1, 2, 4, 8 or 16 lanes.
    offset:swizzle(REVERSE,{2..32})                         Specifies a reverse mode.

                                                            Reverses the lanes for groups of 2, 4, 8, 16 or 32 lanes.
    ======================================================= ===========================================================

Numeric parameters may be specified as either :ref:`integer numbers<amdgpu_synid_integer_number>` or
:ref:`absolute expressions<amdgpu_synid_absolute_expression>`.

Examples:

.. parsed-literal::

  offset:255
  offset:0xffff
  offset:swizzle(QUAD_PERM, 0, 1, 2 ,3)
  offset:swizzle(BITMASK_PERM, "01pi0")
  offset:swizzle(BROADCAST, 2, 0)
  offset:swizzle(SWAP, 8)
  offset:swizzle(REVERSE, 30 + 2)

.. _amdgpu_synid_gds:

gds
~~~

Specifies whether to use GDS or LDS memory (LDS is the default).

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    gds                                      Use GDS memory.
    ======================================== ================================================


EXP Modifiers
-------------

.. _amdgpu_synid_done:

done
~~~~

Specifies if this is the last export from the shader to the target. By default, current
instruction does not finish an export sequence.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    done                                     Indicates the last export operation.
    ======================================== ================================================

.. _amdgpu_synid_compr:

compr
~~~~~

Indicates if the data are compressed (data are not compressed by default).

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    compr                                    Data are compressed.
    ======================================== ================================================

.. _amdgpu_synid_vm:

vm
~~

Specifies valid mask flag state (off by default).

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    vm                                       Set valid mask flag.
    ======================================== ================================================

FLAT Modifiers
--------------

.. _amdgpu_synid_flat_offset12:

offset12
~~~~~~~~

Specifies an immediate unsigned 12-bit offset, in bytes. The default value is 0.

Cannot be used with *global/scratch* opcodes. GFX9 only.

    ================= ======================================================
    Syntax            Description
    ================= ======================================================
    offset:{0..4095}  Specifies a 12-bit unsigned offset as a positive
                      :ref:`integer number <amdgpu_synid_integer_number>`.
    ================= ======================================================

Examples:

.. parsed-literal::

  offset:4095
  offset:0xff

.. _amdgpu_synid_flat_offset13s:

offset13s
~~~~~~~~~

Specifies an immediate signed 13-bit offset, in bytes. The default value is 0.

Can be used with *global/scratch* opcodes only. GFX9 only.

    ============================ =======================================================
    Syntax                       Description
    ============================ =======================================================
    offset:{-4096..4095}         Specifies a 13-bit signed offset as an
                                 :ref:`integer number <amdgpu_synid_integer_number>`.
    ============================ =======================================================

Examples:

.. parsed-literal::

  offset:-4000
  offset:0x10

glc
~~~

See a description :ref:`here<amdgpu_synid_glc>`.

slc
~~~

See a description :ref:`here<amdgpu_synid_slc>`.

tfe
~~~

See a description :ref:`here<amdgpu_synid_tfe>`.

nv
~~

See a description :ref:`here<amdgpu_synid_nv>`.

MIMG Modifiers
--------------

.. _amdgpu_synid_dmask:

dmask
~~~~~

Specifies which channels (image components) are used by the operation. By default, no channels
are used.

    =============== =====================================================
    Syntax          Description
    =============== =====================================================
    dmask:{0..15}   Specifies image channels as a positive
                    :ref:`integer number <amdgpu_synid_integer_number>`.

                    Each bit corresponds to one of 4 image
                    components (RGBA).

                    If the specified bit value
                    is 0, the component is not used, value 1 means
                    that the component is used.
    =============== =====================================================

This modifier has some limitations depending on instruction kind:

    =================================================== ========================
    Instruction Kind                                    Valid dmask Values
    =================================================== ========================
    32-bit atomic *cmpswap*                             0x3
    32-bit atomic instructions except for *cmpswap*     0x1
    64-bit atomic *cmpswap*                             0xF
    64-bit atomic instructions except for *cmpswap*     0x3
    *gather4*                                           0x1, 0x2, 0x4, 0x8
    Other instructions                                  any value
    =================================================== ========================

Examples:

.. parsed-literal::

  dmask:0xf
  dmask:0b1111
  dmask:3

.. _amdgpu_synid_unorm:

unorm
~~~~~

Specifies whether the address is normalized or not (the address is normalized by default).

    ======================== ========================================
    Syntax                   Description
    ======================== ========================================
    unorm                    Force the address to be unnormalized.
    ======================== ========================================

glc
~~~

See a description :ref:`here<amdgpu_synid_glc>`.

slc
~~~

See a description :ref:`here<amdgpu_synid_slc>`.

.. _amdgpu_synid_r128:

r128
~~~~

Specifies texture resource size. The default size is 256 bits.

GFX7 and GFX8 only.

    =================== ================================================
    Syntax              Description
    =================== ================================================
    r128                Specifies 128 bits texture resource size.
    =================== ================================================

.. WARNING:: Using this modifier should descrease *rsrc* operand size from 8 to 4 dwords, but assembler does not currently support this feature.

tfe
~~~

See a description :ref:`here<amdgpu_synid_tfe>`.

.. _amdgpu_synid_lwe:

lwe
~~~

Specifies LOD warning status (LOD warning is disabled by default).

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    lwe                                      Enables LOD warning.
    ======================================== ================================================

.. _amdgpu_synid_da:

da
~~

Specifies if an array index must be sent to TA. By default, array index is not sent.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    da                                       Send an array-index to TA.
    ======================================== ================================================

.. _amdgpu_synid_d16:

d16
~~~

Specifies data size: 16 or 32 bits (32 bits by default). Not supported by GFX7.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    d16                                      Enables 16-bits data mode.

                                             On loads, convert data in memory to 16-bit
                                             format before storing it in VGPRs.

                                             For stores, convert 16-bit data in VGPRs to
                                             32 bits before going to memory.

                                             Note that GFX8.0 does not support data packing.
                                             Each 16-bit data element occupies 1 VGPR.

                                             GFX8.1 and GFX9 support data packing.
                                             Each pair of 16-bit data elements 
                                             occupies 1 VGPR.
    ======================================== ================================================

.. _amdgpu_synid_a16:

a16
~~~

Specifies size of image address components: 16 or 32 bits (32 bits by default). GFX9 only.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    a16                                      Enables 16-bits image address components.
    ======================================== ================================================

Miscellaneous Modifiers
-----------------------

.. _amdgpu_synid_glc:

glc
~~~

This modifier has different meaning for loads, stores, and atomic operations.
The default value is off (0).

See AMD documentation for details.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    glc                                      Set glc bit to 1.
    ======================================== ================================================

.. _amdgpu_synid_slc:

slc
~~~

Specifies cache policy. The default value is off (0).

See AMD documentation for details.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    slc                                      Set slc bit to 1.
    ======================================== ================================================

.. _amdgpu_synid_tfe:

tfe
~~~

Controls access to partially resident textures. The default value is off (0).

See AMD documentation for details.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    tfe                                      Set tfe bit to 1.
    ======================================== ================================================

.. _amdgpu_synid_nv:

nv
~~

Specifies if instruction is operating on non-volatile memory. By default, memory is volatile.

GFX9 only.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    nv                                       Indicates that instruction operates on
                                             non-volatile memory.
    ======================================== ================================================

MUBUF/MTBUF Modifiers
---------------------

.. _amdgpu_synid_idxen:

idxen
~~~~~

Specifies whether address components include an index. By default, no components are used.

Can be used together with :ref:`offen<amdgpu_synid_offen>`.

Cannot be used with :ref:`addr64<amdgpu_synid_addr64>`.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    idxen                                    Address components include an index.
    ======================================== ================================================

.. _amdgpu_synid_offen:

offen
~~~~~

Specifies whether address components include an offset. By default, no components are used.

Can be used together with :ref:`idxen<amdgpu_synid_idxen>`.

Cannot be used with :ref:`addr64<amdgpu_synid_addr64>`.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    offen                                    Address components include an offset.
    ======================================== ================================================

.. _amdgpu_synid_addr64:

addr64
~~~~~~

Specifies whether a 64-bit address is used. By default, no address is used.

GFX7 only. Cannot be used with :ref:`offen<amdgpu_synid_offen>` and
:ref:`idxen<amdgpu_synid_idxen>` modifiers.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    addr64                                   A 64-bit address is used.
    ======================================== ================================================

.. _amdgpu_synid_buf_offset12:

offset12
~~~~~~~~

Specifies an immediate unsigned 12-bit offset, in bytes. The default value is 0.

    =============================== ======================================================
    Syntax                          Description
    =============================== ======================================================
    offset:{0..0xFFF}               Specifies a 12-bit unsigned offset as a positive
                                    :ref:`integer number <amdgpu_synid_integer_number>`.
    =============================== ======================================================

Examples:

.. parsed-literal::

  offset:0
  offset:0x10

glc
~~~

See a description :ref:`here<amdgpu_synid_glc>`.

slc
~~~

See a description :ref:`here<amdgpu_synid_slc>`.

.. _amdgpu_synid_lds:

lds
~~~

Specifies where to store the result: VGPRs or LDS (VGPRs by default).

    ======================================== ===========================
    Syntax                                   Description
    ======================================== ===========================
    lds                                      Store result in LDS.
    ======================================== ===========================

tfe
~~~

See a description :ref:`here<amdgpu_synid_tfe>`.

.. _amdgpu_synid_dfmt:

dfmt
~~~~

TBD

.. _amdgpu_synid_nfmt:

nfmt
~~~~

TBD

SMRD/SMEM Modifiers
-------------------

glc
~~~

See a description :ref:`here<amdgpu_synid_glc>`.

nv
~~

See a description :ref:`here<amdgpu_synid_nv>`.

VINTRP Modifiers
----------------

.. _amdgpu_synid_high:

high
~~~~

Specifies which half of the LDS word to use. Low half of LDS word is used by default.
GFX9 only.

    ======================================== ================================
    Syntax                                   Description
    ======================================== ================================
    high                                     Use high half of LDS word.
    ======================================== ================================

VOP1/VOP2 DPP Modifiers
-----------------------

GFX8 and GFX9 only.

.. _amdgpu_synid_dpp_ctrl:

dpp_ctrl
~~~~~~~~

Specifies how data are shared between threads. This is a mandatory modifier.
There is no default value.

Note. The lanes of a wavefront are organized in four banks and four rows.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    quad_perm:[{0..3},{0..3},{0..3},{0..3}]  Full permute of 4 threads.
    row_mirror                               Mirror threads within row.
    row_half_mirror                          Mirror threads within 1/2 row (8 threads).
    row_bcast:15                             Broadcast 15th thread of each row to next row.
    row_bcast:31                             Broadcast thread 31 to rows 2 and 3.
    wave_shl:1                               Wavefront left shift by 1 thread.
    wave_rol:1                               Wavefront left rotate by 1 thread.
    wave_shr:1                               Wavefront right shift by 1 thread.
    wave_ror:1                               Wavefront right rotate by 1 thread.
    row_shl:{1..15}                          Row shift left by 1-15 threads.
    row_shr:{1..15}                          Row shift right by 1-15 threads.
    row_ror:{1..15}                          Row rotate right by 1-15 threads.
    ======================================== ================================================

Note: Numeric parameters may be specified as either
:ref:`integer numbers<amdgpu_synid_integer_number>` or
:ref:`absolute expressions<amdgpu_synid_absolute_expression>`.

Examples:

.. parsed-literal::

  quad_perm:[0, 1, 2, 3]
  row_shl:3

.. _amdgpu_synid_row_mask:

row_mask
~~~~~~~~

Controls which rows are enabled for data sharing. By default, all rows are enabled.

Note. The lanes of a wavefront are organized in four banks and four rows.

    ======================================== =====================================================
    Syntax                                   Description
    ======================================== =====================================================
    row_mask:{0..15}                         Specifies a *row mask* as a positive
                                             :ref:`integer number <amdgpu_synid_integer_number>`.

                                             Each of 4 bits in the mask controls one
                                             row (0 - disabled, 1 - enabled).
    ======================================== =====================================================

Examples:

.. parsed-literal::

  row_mask:0xf
  row_mask:0b1010
  row_mask:0b1111

.. _amdgpu_synid_bank_mask:

bank_mask
~~~~~~~~~

Controls which banks are enabled for data sharing. By default, all banks are enabled.

Note. The lanes of a wavefront are organized in four banks and four rows.

    ======================================== =======================================================
    Syntax                                   Description
    ======================================== =======================================================
    bank_mask:{0..15}                        Specifies a *bank mask* as a positive
                                             :ref:`integer number <amdgpu_synid_integer_number>`.

                                             Each of 4 bits in the mask controls one
                                             bank (0 - disabled, 1 - enabled).
    ======================================== =======================================================

Examples:

.. parsed-literal::

  bank_mask:0x3
  bank_mask:0b0011
  bank_mask:0b1111

.. _amdgpu_synid_bound_ctrl:

bound_ctrl
~~~~~~~~~~

Controls data sharing when accessing an invalid lane. By default, data sharing with
invalid lanes is disabled.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    bound_ctrl:0                             Enables data sharing with invalid lanes.

                                             Accessing data from an invalid lane will
                                             return zero.
    ======================================== ================================================

VOP1/VOP2/VOPC SDWA Modifiers
-----------------------------

GFX8 and GFX9 only.

clamp
~~~~~

See a description :ref:`here<amdgpu_synid_clamp>`.

omod
~~~~

See a description :ref:`here<amdgpu_synid_omod>`.

GFX9 only.

.. _amdgpu_synid_dst_sel:

dst_sel
~~~~~~~

Selects which bits in the destination are affected. By default, all bits are affected.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    dst_sel:DWORD                            Use bits 31:0.
    dst_sel:BYTE_0                           Use bits 7:0.
    dst_sel:BYTE_1                           Use bits 15:8.
    dst_sel:BYTE_2                           Use bits 23:16.
    dst_sel:BYTE_3                           Use bits 31:24.
    dst_sel:WORD_0                           Use bits 15:0.
    dst_sel:WORD_1                           Use bits 31:16.
    ======================================== ================================================


.. _amdgpu_synid_dst_unused:

dst_unused
~~~~~~~~~~

Controls what to do with the bits in the destination which are not selected
by :ref:`dst_sel<amdgpu_synid_dst_sel>`.
By default, unused bits are preserved.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    dst_unused:UNUSED_PAD                    Pad with zeros.
    dst_unused:UNUSED_SEXT                   Sign-extend upper bits, zero lower bits.
    dst_unused:UNUSED_PRESERVE               Preserve bits.
    ======================================== ================================================

.. _amdgpu_synid_src0_sel:

src0_sel
~~~~~~~~

Controls which bits in the src0 are used. By default, all bits are used.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    src0_sel:DWORD                           Use bits 31:0.
    src0_sel:BYTE_0                          Use bits 7:0.
    src0_sel:BYTE_1                          Use bits 15:8.
    src0_sel:BYTE_2                          Use bits 23:16.
    src0_sel:BYTE_3                          Use bits 31:24.
    src0_sel:WORD_0                          Use bits 15:0.
    src0_sel:WORD_1                          Use bits 31:16.
    ======================================== ================================================

.. _amdgpu_synid_src1_sel:

src1_sel
~~~~~~~~

Controls which bits in the src1 are used. By default, all bits are used.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    src1_sel:DWORD                           Use bits 31:0.
    src1_sel:BYTE_0                          Use bits 7:0.
    src1_sel:BYTE_1                          Use bits 15:8.
    src1_sel:BYTE_2                          Use bits 23:16.
    src1_sel:BYTE_3                          Use bits 31:24.
    src1_sel:WORD_0                          Use bits 15:0.
    src1_sel:WORD_1                          Use bits 31:16.
    ======================================== ================================================

.. _amdgpu_synid_sdwa_operand_modifiers:

VOP1/VOP2/VOPC SDWA Operand Modifiers
-------------------------------------

Operand modifiers are not used separately. They are applied to source operands.

GFX8 and GFX9 only.

abs
~~~

See a description :ref:`here<amdgpu_synid_abs>`.

neg
~~~

See a description :ref:`here<amdgpu_synid_neg>`.

.. _amdgpu_synid_sext:

sext
~~~~

Sign-extends value of a (sub-dword) operand to fill all 32 bits.
Has no effect for 32-bit operands.

Valid for integer operands only.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    sext(<operand>)                          Sign-extend operand value.
    ======================================== ================================================

Examples:

.. parsed-literal::

  sext(v4)
  sext(v255)

VOP3 Modifiers
--------------

.. _amdgpu_synid_vop3_op_sel:

op_sel
~~~~~~

Selects the low [15:0] or high [31:16] operand bits for source and destination operands.
By default, low bits are used for all operands.

The number of values specified with the op_sel modifier must match the number of instruction
operands (both source and destination). First value controls src0, second value controls src1
and so on, except that the last value controls destination.
The value 0 selects the low bits, while 1 selects the high bits.

Note. op_sel modifier affects 16-bit operands only. For 32-bit operands the value specified
by op_sel must be 0.

GFX9 only.

    ======================================== ============================================================
    Syntax                                   Description
    ======================================== ============================================================
    op_sel:[{0..1},{0..1}]                   Select operand bits for instructions with 1 source operand.
    op_sel:[{0..1},{0..1},{0..1}]            Select operand bits for instructions with 2 source operands.
    op_sel:[{0..1},{0..1},{0..1},{0..1}]     Select operand bits for instructions with 3 source operands.
    ======================================== ============================================================

Examples:

.. parsed-literal::

  op_sel:[0,0]
  op_sel:[0,1]

.. _amdgpu_synid_clamp:

clamp
~~~~~

Clamp meaning depends on instruction.

For *v_cmp* instructions, clamp modifier indicates that the compare signals
if a floating point exception occurs. By default, signaling is disabled.
Not supported by GFX7.

For integer operations, clamp modifier indicates that the result must be clamped
to the largest and smallest representable value. By default, there is no clamping.
Integer clamping is not supported by GFX7.

For floating point operations, clamp modifier indicates that the result must be clamped
to the range [0.0, 1.0]. By default, there is no clamping.

Note. Clamp modifier is applied after :ref:`output modifiers<amdgpu_synid_omod>` (if any).

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    clamp                                    Enables clamping (or signaling).
    ======================================== ================================================

.. _amdgpu_synid_omod:

omod
~~~~

Specifies if an output modifier must be applied to the result.
By default, no output modifiers are applied.

Note. Output modifiers are applied before :ref:`clamping<amdgpu_synid_clamp>` (if any).

Output modifiers are valid for f32 and f64 floating point results only.
They must not be used with f16.

Note. *v_cvt_f16_f32* is an exception. This instruction produces f16 result
but accepts output modifiers.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    mul:2                                    Multiply the result by 2.
    mul:4                                    Multiply the result by 4.
    div:2                                    Multiply the result by 0.5.
    ======================================== ================================================

.. _amdgpu_synid_vop3_operand_modifiers:

VOP3 Operand Modifiers
----------------------

Operand modifiers are not used separately. They are applied to source operands.

.. _amdgpu_synid_abs:

abs
~~~

Computes absolute value of its operand. Applied before :ref:`neg<amdgpu_synid_neg>` (if any).
Valid for floating point operands only.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    abs(<operand>)                           Get absolute value of operand.
    \|<operand>|                             The same as above.
    ======================================== ================================================

Examples:

.. parsed-literal::

  abs(v36)
  \|v36|

.. _amdgpu_synid_neg:

neg
~~~

Computes negative value of its operand. Applied after :ref:`abs<amdgpu_synid_abs>` (if any).
Valid for floating point operands only.

    ======================================== ================================================
    Syntax                                   Description
    ======================================== ================================================
    neg(<operand>)                           Get negative value of operand.
    -<operand>                               The same as above.
    ======================================== ================================================

Examples:

.. parsed-literal::

  neg(v[0])
  -v4

VOP3P Modifiers
---------------

This section describes modifiers of *regular* VOP3P instructions.

*v_mad_mix_f32*, *v_mad_mixhi_f16* and *v_mad_mixlo_f16*
instructions use these modifiers :ref:`in a special manner<amdgpu_synid_mad_mix>`.

GFX9 only.

.. _amdgpu_synid_op_sel:

op_sel
~~~~~~

Selects the low [15:0] or high [31:16] operand bits as input to the operation
which results in the lower-half of the destination.
By default, low bits are used for all operands.

The number of values specified by the *op_sel* modifier must match the number of source
operands. First value controls src0, second value controls src1 and so on.

The value 0 selects the low bits, while 1 selects the high bits.

    ================================= =============================================================
    Syntax                            Description
    ================================= =============================================================
    op_sel:[{0..1}]                   Select operand bits for instructions with 1 source operand.
    op_sel:[{0..1},{0..1}]            Select operand bits for instructions with 2 source operands.
    op_sel:[{0..1},{0..1},{0..1}]     Select operand bits for instructions with 3 source operands.
    ================================= =============================================================

Examples:

.. parsed-literal::

  op_sel:[0,0]
  op_sel:[0,1,0]

.. _amdgpu_synid_op_sel_hi:

op_sel_hi
~~~~~~~~~

Selects the low [15:0] or high [31:16] operand bits as input to the operation
which results in the upper-half of the destination.
By default, high bits are used for all operands.

The number of values specified by the *op_sel_hi* modifier must match the number of source
operands. First value controls src0, second value controls src1 and so on.

The value 0 selects the low bits, while 1 selects the high bits.

    =================================== =============================================================
    Syntax                              Description
    =================================== =============================================================
    op_sel_hi:[{0..1}]                  Select operand bits for instructions with 1 source operand.
    op_sel_hi:[{0..1},{0..1}]           Select operand bits for instructions with 2 source operands.
    op_sel_hi:[{0..1},{0..1},{0..1}]    Select operand bits for instructions with 3 source operands.
    =================================== =============================================================

Examples:

.. parsed-literal::

  op_sel_hi:[0,0]
  op_sel_hi:[0,0,1]

.. _amdgpu_synid_neg_lo:

neg_lo
~~~~~~

Specifies whether to change sign of operand values selected by
:ref:`op_sel<amdgpu_synid_op_sel>`. These values are then used
as input to the operation which results in the upper-half of the destination.

The number of values specified by this modifier must match the number of source
operands. First value controls src0, second value controls src1 and so on.

The value 0 indicates that the corresponding operand value is used unmodified,
the value 1 indicates that negative value of the operand must be used.

By default, operand values are used unmodified.

This modifier is valid for floating point operands only.

    ================================ ==================================================================
    Syntax                           Description
    ================================ ==================================================================
    neg_lo:[{0..1}]                  Select affected operands for instructions with 1 source operand.
    neg_lo:[{0..1},{0..1}]           Select affected operands for instructions with 2 source operands.
    neg_lo:[{0..1},{0..1},{0..1}]    Select affected operands for instructions with 3 source operands.
    ================================ ==================================================================

Examples:

.. parsed-literal::

  neg_lo:[0]
  neg_lo:[0,1]

.. _amdgpu_synid_neg_hi:

neg_hi
~~~~~~

Specifies whether to change sign of operand values selected by
:ref:`op_sel_hi<amdgpu_synid_op_sel_hi>`. These values are then used
as input to the operation which results in the upper-half of the destination.

The number of values specified by this modifier must match the number of source
operands. First value controls src0, second value controls src1 and so on.

The value 0 indicates that the corresponding operand value is used unmodified,
the value 1 indicates that negative value of the operand must be used.

By default, operand values are used unmodified.

This modifier is valid for floating point operands only.

    =============================== ==================================================================
    Syntax                          Description
    =============================== ==================================================================
    neg_hi:[{0..1}]                 Select affected operands for instructions with 1 source operand.
    neg_hi:[{0..1},{0..1}]          Select affected operands for instructions with 2 source operands.
    neg_hi:[{0..1},{0..1},{0..1}]   Select affected operands for instructions with 3 source operands.
    =============================== ==================================================================

Examples:

.. parsed-literal::

  neg_hi:[1,0]
  neg_hi:[0,1,1]

clamp
~~~~~

See a description :ref:`here<amdgpu_synid_clamp>`.

.. _amdgpu_synid_mad_mix:

VOP3P V_MAD_MIX Modifiers
-------------------------

*v_mad_mix_f32*, *v_mad_mixhi_f16* and *v_mad_mixlo_f16* instructions
use *op_sel* and *op_sel_hi* modifiers 
in a manner different from *regular* VOP3P instructions.

See a description below.

GFX9 only.

.. _amdgpu_synid_mad_mix_op_sel:

m_op_sel
~~~~~~~~

This operand has meaning only for 16-bit source operands as indicated by
:ref:`m_op_sel_hi<amdgpu_synid_mad_mix_op_sel_hi>`.
It specifies to select either the low [15:0] or high [31:16] operand bits
as input to the operation.

The number of values specified by the *op_sel* modifier must match the number of source
operands. First value controls src0, second value controls src1 and so on.

The value 0 indicates the low bits, the value 1 indicates the high 16 bits.

By default, low bits are used for all operands.

    =============================== ================================================
    Syntax                          Description
    =============================== ================================================
    op_sel:[{0..1},{0..1},{0..1}]   Select location of each 16-bit source operand.
    =============================== ================================================

Examples:

.. parsed-literal::

  op_sel:[0,1]

.. _amdgpu_synid_mad_mix_op_sel_hi:

m_op_sel_hi
~~~~~~~~~~~

Selects the size of source operands: either 32 bits or 16 bits.
By default, 32 bits are used for all source operands.

The number of values specified by the *op_sel_hi* modifier must match the number of source
operands. First value controls src0, second value controls src1 and so on.

The value 0 indicates 32 bits, the value 1 indicates 16 bits.

The location of 16 bits in the operand may be specified by
:ref:`m_op_sel<amdgpu_synid_mad_mix_op_sel>`.

    ======================================== ====================================
    Syntax                                   Description
    ======================================== ====================================
    op_sel_hi:[{0..1},{0..1},{0..1}]         Select size of each source operand.
    ======================================== ====================================

Examples:

.. parsed-literal::

  op_sel_hi:[1,1,1]

abs
~~~

See a description :ref:`here<amdgpu_synid_abs>`.

neg
~~~

See a description :ref:`here<amdgpu_synid_neg>`.

clamp
~~~~~

See a description :ref:`here<amdgpu_synid_clamp>`.