diff options
Diffstat (limited to 'src/arm32/shifter')
| -rw-r--r-- | src/arm32/shifter/mod.rs | 44 |
1 files changed, 34 insertions, 10 deletions
diff --git a/src/arm32/shifter/mod.rs b/src/arm32/shifter/mod.rs index e5da07b..f658c2b 100644 --- a/src/arm32/shifter/mod.rs +++ b/src/arm32/shifter/mod.rs @@ -19,30 +19,50 @@ // fero General Public License along with Pollex. // If not, see <https://www.gnu.org/licenses/>. -use crate::arm32::{Register, Unsigned}; +use crate::arm32::Register; use core::fmt::Display; /// A shifter operand. +/// +/// Some Arm instructions take these to minimise instruction usage. +/// For example, the following code: +/// +/// ```as +/// LSL r1, r1, #2 +/// ADD r0, r1 +/// ``` +/// +/// is functionally equivalent to: +/// +/// ```as +/// ADD r0, r1, LSL #2 +/// ``` +/// +/// In fact, the first example will encode identically to the following: +/// +/// ```as +/// MOV r1, r1, LSL #2 +/// ``` #[derive(Clone, Copy, Debug, Eq, PartialEq)] pub enum Shifter { - ArithmeticShiftRightImmediate { source: Register, shift: Unsigned }, + ArithmeticShiftRightImmediate { source: Register, shift: u32 }, ArithmeticShiftRightRegister { source: Register, shift: Register }, - Immediate { immediate: Unsigned }, + Immediate { immediate: u32 }, - LogicalShiftLeftImmediate { source: Register, shift: Unsigned }, + LogicalShiftLeftImmediate { source: Register, shift: u32 }, LogicalShiftLeftRegister { source: Register, shift: Register }, - LogicalShiftRightImmediate { source: Register, shift: Unsigned }, + LogicalShiftRightImmediate { source: Register, shift: u32 }, LogicalShiftRightRegister { source: Register, shift: Register }, RotateRightExtend { source: Register }, - RotateRightImmediate { source: Register, shift: Unsigned }, + RotateRightImmediate { source: Register, shift: u32 }, RotateRightRegister { source: Register, shift: Register }, } @@ -53,7 +73,7 @@ impl Display for Shifter { match *self { ArithmeticShiftRightImmediate { source, shift } => { - write!(f, "{source}, ASR {shift}") + write!(f, "{source}, ASR #{shift}") }, ArithmeticShiftRightRegister { source, shift } => { @@ -64,8 +84,12 @@ impl Display for Shifter { write!(f, "#{immediate}<") }, + LogicalShiftLeftImmediate { source, shift: 0x0 } => { + write!(f, "{source}") + }, + LogicalShiftLeftImmediate { source, shift } => { - write!(f, "{source}, LSL {shift}") + write!(f, "{source}, LSL #{shift}") }, LogicalShiftLeftRegister { source, shift } => { @@ -73,7 +97,7 @@ impl Display for Shifter { }, LogicalShiftRightImmediate { source, shift } => { - write!(f, "{source}, LSR {shift}") + write!(f, "{source}, LSR #{shift}") }, LogicalShiftRightRegister { source, shift } => { @@ -85,7 +109,7 @@ impl Display for Shifter { }, RotateRightImmediate { source, shift } => { - write!(f, "{source}, ROR {shift}") + write!(f, "{source}, ROR #{shift}") }, RotateRightRegister { source, shift } => { |