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Diffstat (limited to 'src/arm32/predicate')
-rw-r--r-- | src/arm32/predicate/mod.rs | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/src/arm32/predicate/mod.rs b/src/arm32/predicate/mod.rs new file mode 100644 index 0000000..0b761d9 --- /dev/null +++ b/src/arm32/predicate/mod.rs @@ -0,0 +1,74 @@ +// Copyright 2024 Gabriel Bjørnager Jensen. +// +// This file is part of Pollex. +// +// Pollex is free software: you can redistribute it +// and/or modify it under the terms of the GNU Af- +// fero General Public License as published by the +// Free Software Foundation, either version 3 of +// the License, or (at your option) any later ver- +// sion. +// +// Pollex is distributed in the hope that it will +// be useful, but WITHOUT ANY WARRANTY; without +// even the implied warranty of MERCHANTABILITY or +// FITNESS FOR A PARTICULAR PURPOSE. See the GNU +// Affero General Public License for more details. +// +// You should have received a copy of the GNU Af- +// fero General Public License along with Pollex. +// If not, see <https://www.gnu.org/licenses/>. + +use core::fmt::Display; + +/// An instruction predicate (condition code). +/// +/// Most Arm32 opcodes embed a condition code, as well as some Thumb opcodes. +/// +/// Any 4-bit values is always a valid predicate *except* `0b1111`, which sometimes denotes a different instruction altogether +/// In most cases, it is invalid, however.. +#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)] +#[repr(u8)] +pub enum Predicate { + Equal = 0b0000, + NotEqual = 0b0001, + HigherOrSame = 0b0010, + Lower = 0b0011, + Minus = 0b0100, + Plus = 0b0101, + Overflow = 0b0110, + NoOverflow = 0b0111, + Higher = 0b1000, + LowerOrSame = 0b1001, + GreaterThanOrEqual = 0b1010, + LessThan = 0b1011, + GreaterThan = 0b1100, + LessThanOrEqual = 0b1101, + Always = 0b1110, + //Never = 0b1111, +} + +impl Display for Predicate { + fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { + use Predicate::*; + + match *self { + Equal => write!(f, "EQ"), + NotEqual => write!(f, "NE"), + HigherOrSame => write!(f, "HS"), + Lower => write!(f, "LO"), + Minus => write!(f, "MI"), + Plus => write!(f, "PL"), + Overflow => write!(f, "VS"), + NoOverflow => write!(f, "VC"), + Higher => write!(f, "HI"), + LowerOrSame => write!(f, "LS"), + GreaterThanOrEqual => write!(f, "GE"), + LessThan => write!(f, "LT"), + GreaterThan => write!(f, "GT"), + LessThanOrEqual => write!(f, "LE"), + Always => Ok(()), // No need to print this one. + //Never => write!(f, "NV"), + } + } +} |