bpf/standardization/instruction-set.rst

11 operating system kernel. This document specifies the BPF instruction
134 instruction has one or more conformance groups of which it is a member.
152 BPF has two instruction encodings:
154 * the basic instruction encoding, which uses 64 bits to encode an instruction
155 * the wide instruction encoding, which appends a second 64 bits
156   after the basic instruction for a total of 128 bits.
158 Basic instruction encoding
161 A basic instruction is encoded as follows::
177     The format of these bits varies by instruction class
180     The instruction class (see `Instruction classes`_)
227 Wide instruction encoding
230 Some instructions are defined to use the wide instruction encoding,
232 the basic instruction format contain a pseudo instruction
270 The three least significant bits of the 'opcode' field store the instruction class:
298   the operation code, whose meaning varies by instruction class
312 **instruction class**
313   the instruction class (see `Instruction classes`_)
401 The ``MOVSX`` instruction does a move operation with sign extension.
421 The ``NEG`` instruction is only defined when the source bit is clear
430 The byte swap instructions use instruction classes of ``ALU`` and ``ALU64``
510 is in units of 64-bit instructions relative to the instruction following
511 the jump instruction.  Thus 'PC += 1' skips execution of the next
512 instruction if it's a basic instruction or results in undefined behavior
513 if the next instruction is a 128-bit wide instruction.
565 caller, and are referenced by offset from the instruction following the call
566 instruction, similar to ``JA``.  The offset is encoded in the 'imm' field of
567 the call instruction. An ``EXIT`` within the program-local function will
613   The instruction class (see `Instruction classes`_)
719 Instructions with the ``IMM`` 'mode' modifier use the wide instruction
721 basic instruction to hold an opcode subtype.
747 * code_addr(imm) gets the address of the instruction at a specified relative offset in number of (6…
763 index in the set associated with the BPF program containing the instruction.
777 carried over from classic BPF. These instructions used an instruction