Module format

A DSL for describing x64 instruction formats–the shape of the operands.

Every instruction has a format that corresponds to its encoding’s expected operands. The format is what allows us to generate code that accepts operands of the right type and check that the operands are used in the right way.

The entry point for this module is fmt.

let f = fmt("rm", [rw(r32), r(rm32)]);
assert_eq!(f.to_string(), "rm(r32[rw], rm32)")

Structs

Format

A format describes the operands for an instruction.

Operand

An x64 operand.

Enums

Eflags

Describes if an instruction uses EFLAGS, and whether it reads, writes, or reads/writes the EFLAGS register. In the future, we might want to model specific EFLAGS bits instead of the entire EFLAGS register. Some related discussion in this GitHub issue https://github.com/bytecodealliance/wasmtime/issues/10298

Extension

x64 operands may be sign- or zero-extended.

Location

An operand location, as expressed in Intel’s Instruction Set Reference.

Mutability

x64 operands can be mutable or not.

OperandKind

Organize the operand locations by kind.

RegClass

The kind of register used in a Location.

Functions

align

An abbreviated constructor for a memory operand that requires alignment.

fmt

An abbreviated constructor for an instruction “format.”

implicit

An abbreviated constructor for an operand that is used by the instruction but not visible in its disassembly.

r

An abbreviated constructor for a “read” operand.

rw

An abbreviated constructor for a “read-write” operand.

sxl

An abbreviated constructor for a “read” operand that is sign-extended to 32 bits (longword).

sxq

An abbreviated constructor for a “read” operand that is sign-extended to 64 bits (quadword).

sxw

An abbreviated constructor for a “read” operand that is sign-extended to 16 bits (word).

w

An abbreviated constructor for a “write” operand.