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/// Various instructions in A64 can have condition codes attached. This enum
/// includes all of the various kinds of conditions along with their respective
/// encodings.
pub struct Condition;
impl Condition {
pub const EQ: u8 = 0b0000; // equal to
pub const NE: u8 = 0b0001; // not equal to
pub const CS: u8 = 0b0010; // carry set (alias for HS)
pub const CC: u8 = 0b0011; // carry clear (alias for LO)
pub const MI: u8 = 0b0100; // minus, negative
pub const PL: u8 = 0b0101; // positive or zero
pub const VS: u8 = 0b0110; // signed overflow
pub const VC: u8 = 0b0111; // no signed overflow
pub const HI: u8 = 0b1000; // greater than (unsigned)
pub const LS: u8 = 0b1001; // less than or equal to (unsigned)
pub const GE: u8 = 0b1010; // greater than or equal to (signed)
pub const LT: u8 = 0b1011; // less than (signed)
pub const GT: u8 = 0b1100; // greater than (signed)
pub const LE: u8 = 0b1101; // less than or equal to (signed)
pub const AL: u8 = 0b1110; // always
pub const fn inverse(condition: u8) -> u8 {
match condition {
Condition::EQ => Condition::NE,
Condition::NE => Condition::EQ,
Condition::CS => Condition::CC,
Condition::CC => Condition::CS,
Condition::MI => Condition::PL,
Condition::PL => Condition::MI,
Condition::VS => Condition::VC,
Condition::VC => Condition::VS,
Condition::HI => Condition::LS,
Condition::LS => Condition::HI,
Condition::LT => Condition::GE,
Condition::GE => Condition::LT,
Condition::GT => Condition::LE,
Condition::LE => Condition::GT,
Condition::AL => Condition::AL,
_ => panic!("Unknown condition")
}
}
}
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