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#### 9.7.4 Opcodes

In the instruction descriptions below the following field descriptors are used:

`%d`

  Destination general-purpose register whose role is to be destination of an operation.

`%s`

  Source general-purpose register whose role is to be the source of an operation.

`disp16`

  16-bit signed PC-relative offset, measured in number of 64-bit words, minus one.

`disp32`

  32-bit signed PC-relative offset, measured in number of 64-bit words, minus one.

`offset16`

  Signed 16-bit immediate.

`imm32`

  Signed 32-bit immediate.

`imm64`

  Signed 64-bit immediate.

#### 9.7.4.1 Arithmetic instructions

The destination register in these instructions act like an accumulator.

`add %d, (%s|imm32)`

  64-bit arithmetic addition.

`sub %d, (%s|imm32)`

  64-bit arithmetic subtraction.

`mul %d, (%s|imm32)`

  64-bit arithmetic multiplication.

`div %d, (%s|imm32)`

  64-bit arithmetic integer division.

`mod %d, (%s|imm32)`

  64-bit integer remainder.

`and %d, (%s|imm32)`

  64-bit bit-wise “and” operation.

`or %d, (%s|imm32)`

  64-bit bit-wise “or” operation.

`xor %d, (%s|imm32)`

  64-bit bit-wise exclusive-or operation.

`lsh %d, (%s|imm32)`

  64-bit left shift, by `%s` or `imm32` bits.

`rsh %d, (%s|imm32)`

  64-bit right logical shift, by `%s` or `imm32` bits.

`arsh %d, (%s|imm32)`

  64-bit right arithmetic shift, by `%s` or `imm32` bits.

`neg %d`

  64-bit arithmetic negation.

`mov %d, (%s|imm32)`

  Move the 64-bit value of `%s` in `%d`, or load `imm32` in `%d`.

#### 9.7.4.2 32-bit arithmetic instructions

The destination register in these instructions act as an accumulator.

`add32 %d, (%s|imm32)`

  32-bit arithmetic addition.

`sub32 %d, (%s|imm32)`

  32-bit arithmetic subtraction.

`mul32 %d, (%s|imm32)`

  32-bit arithmetic multiplication.

`div32 %d, (%s|imm32)`

  32-bit arithmetic integer division.

`mod32 %d, (%s|imm32)`

  32-bit integer remainder.

`and32 %d, (%s|imm32)`

  32-bit bit-wise “and” operation.

`or32 %d, (%s|imm32)`

  32-bit bit-wise “or” operation.

`xor32 %d, (%s|imm32)`

  32-bit bit-wise exclusive-or operation.

`lsh32 %d, (%s|imm32)`

  32-bit left shift, by `%s` or `imm32` bits.

`rsh32 %d, (%s|imm32)`

  32-bit right logical shift, by `%s` or `imm32` bits.

`arsh32 %d, (%s|imm32)`

  32-bit right arithmetic shift, by `%s` or `imm32` bits.

`neg32 %d`

  32-bit arithmetic negation.

`mov32 %d, (%s|imm32)`

  Move the 32-bit value of `%s` in `%d`, or load `imm32` in `%d`.

#### 9.7.4.3 Endianness conversion instructions

`endle %d, (8|16|32)`

  Convert the 8-bit, 16-bit or 32-bit value in `%d` to little-endian.

`endbe %d, (8|16|32)`

  Convert the 8-bit, 16-bit or 32-bit value in `%d` to big-endian.

#### 9.7.4.4 64-bit load and pseudo maps

`lddw %d, imm64`

  Load the given signed 64-bit immediate, or pseudo map descriptor, to the destination register `%d`.

`lddw %d, %map_fd(N)`

  Load the address of the given pseudo map fd N to the destination register `%d`.

#### 9.7.4.5 Load instructions for socket filters

The following instructions are intended to be used in socket filters, and are therefore not general-purpose: they make assumptions on the contents of several registers. See the file `Documentation/networking/filter.txt` in the Linux kernel source tree for more information.

Absolute loads:

`ldabsdw imm32`

  Absolute 64-bit load.

`ldabsw imm32`

  Absolute 32-bit load.

`ldabsh imm32`

  Absolute 16-bit load.

`ldabsb imm32`

  Absolute 8-bit load.

Indirect loads:

`ldinddw %s, imm32`

  Indirect 64-bit load.

`ldindw %s, imm32`

  Indirect 32-bit load.

`ldindh %s, imm32`

  Indirect 16-bit load.

`ldindb %s, imm32`

  Indirect 8-bit load.

#### 9.7.4.6 Generic load/store instructions

General-purpose load and store instructions are provided for several word sizes.

Load to register instructions:

`ldxdw %d, [%s+offset16]`

  Generic 64-bit load.

`ldxw %d, [%s+offset16]`

  Generic 32-bit load.

`ldxh %d, [%s+offset16]`

  Generic 16-bit load.

`ldxb %d, [%s+offset16]`

  Generic 8-bit load.

Store from register instructions:

`stxdw [%d+offset16], %s`

  Generic 64-bit store.

`stxw [%d+offset16], %s`

  Generic 32-bit store.

`stxh [%d+offset16], %s`

  Generic 16-bit store.

`stxb [%d+offset16], %s`

  Generic 8-bit store.

Store from immediates instructions:

`stddw [%d+offset16], imm32`

  Store immediate as 64-bit.

`stdw [%d+offset16], imm32`

  Store immediate as 32-bit.

`stdh [%d+offset16], imm32`

  Store immediate as 16-bit.

`stdb [%d+offset16], imm32`

  Store immediate as 8-bit.

#### 9.7.4.7 Jump instructions

eBPF provides the following compare-and-jump instructions, which compare the values of the two given registers, or the values of a register and an immediate, and perform a branch in case the comparison holds true.

`ja %d,(%s|imm32),disp16`

  Jump-always.

`jeq %d,(%s|imm32),disp16`

  Jump if equal.

`jgt %d,(%s|imm32),disp16`

  Jump if greater.

`jge %d,(%s|imm32),disp16`

  Jump if greater or equal.

`jlt %d,(%s|imm32),disp16`

  Jump if lesser.

`jle %d,(%s|imm32),disp16`

  Jump if lesser or equal.

`jset %d,(%s|imm32),disp16`

  Jump if signed equal.

`jne %d,(%s|imm32),disp16`

  Jump if not equal.

`jsgt %d,(%s|imm32),disp16`

  Jump if signed greater.

`jsge %d,(%s|imm32),disp16`

  Jump if signed greater or equal.

`jslt %d,(%s|imm32),disp16`

  Jump if signed lesser.

`jsle %d,(%s|imm32),disp16`

  Jump if signed lesser or equal.

A call instruction is provided in order to perform calls to other eBPF functions, or to external kernel helpers:

`call (disp32|imm32)`

  Jump and link to the offset disp32, or to the kernel helper function identified by imm32.

Finally:

`exit`

  Terminate the eBPF program.

#### 9.7.4.8 Atomic instructions

Atomic exchange-and-add instructions are provided in two flavors: one for swapping 64-bit quantities and another for 32-bit quantities.

`xadddw [%d+offset16],%s`

  Exchange-and-add a 64-bit value at the specified location.

`xaddw [%d+offset16],%s`

  Exchange-and-add a 32-bit value at the specified location.

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