Enum Register

pub enum Register {
    RegA,
    RegB,
    RegC,
    RegD,
    RegIP,
    RegSP,
    RegR,
    RegS,
    RegE,
    RegF,
    RegG,
    RegH,
}

A register in the CFD-16 Instruction Set Architecture, eight of which are general-purpose (%a, %b, %c, %d, %e, %f, %g, %h), and four of which are system registers which cannot be accessed by user processes, as they are shadowed over in user mode. ( %ip, %sp, %r, %s)

Variants

RegA

General-purpose register. Available in user and kernel mode.

RegB

General-purpose register. Available in user and kernel mode.

RegC

General-purpose register. Available in user and kernel mode.

RegD

General-purpose register. Available in user and kernel mode.

RegIP

This register contains the instruction pointer, i.e. the address (plus 4 bytes due to pipelining) at which the current instruction resides. The branch and jump instructions (br jsr ret are the only way to modify this value when in userspace. This is the only register which is in actuality 24-bit wide to match the size of the ISA’s address space.

RegSP

This register contains the stack pointer, i.e. the address in memory where the top of the stack is currently located. The instructions push and pop modify this value when in userspace.

RegR

This register contains the return address of the last-called function call (through the instruction jsr) and is used by the ret instruction.

RegS

This register contains the status register which is encoded as follows. 0bNZCMPPPP-SSSSSSSS, where N is the negative bit, (when the result of the ALU calculation is negative) Z is the zero bit, (when the result of the ALU calculation is zero), C is the carry bit, (when the ALU carries or overflows in a given integer calculation), M is the mode bit, which indicates whether the current process is in user mode (0) or kernel mode. (1) Ps designate the current process id, which is important for controlling access to segments of memory, and S designates the currently accessed segment in memory.

RegE

General-purpose register. Available only in user mode.

RegF

General-purpose register. Available only in user mode.

RegG

General-purpose register. Available only in user mode.

RegH

General-purpose register. Available only in user mode.

Trait Implementations

impl Clone for Register

fn clone(&self) -> Register

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Codable for Register

fn encode(&self) -> u16

Encodes the instruction or portion thereof.

fn decode(value: u16, mode: Mode) -> Option<Self>

Decodes the instruction given the current mode of execution.

impl Debug for Register

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for Register

fn eq(&self, other: &Register) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Register

impl Eq for Register

impl StructuralPartialEq for Register