1 files changed, 155 insertions, 0 deletions
diff --git a/yjit/src/asm/arm64/inst/mov.rs b/yjit/src/asm/arm64/inst/mov.rs
new file mode 100644
index 0000000000..0d68ffd206
--- /dev/null
+++ b/yjit/src/asm/arm64/inst/mov.rs
@@ -0,0 +1,155 @@
+use super::sf::Sf;
+
+/// Which operation is being performed.
+enum Op {
+    /// A movz operation which zeroes out the other bits.
+    MOVZ = 0b10,
+
+    /// A movk operation which keeps the other bits in place.
+    MOVK = 0b11
+}
+
+/// How much to shift the immediate by.
+enum Hw {
+    LSL0 = 0b00,
+    LSL16 = 0b01,
+    LSL32 = 0b10,
+    LSL48 = 0b11
+}
+
+impl From<u8> for Hw {
+    fn from(shift: u8) -> Self {
+        match shift {
+            0 => Hw::LSL0,
+            16 => Hw::LSL16,
+            32 => Hw::LSL32,
+            48 => Hw::LSL48,
+            _ => panic!("Invalid value for shift: {}", shift)
+        }
+    }
+}
+
+/// The struct that represents a MOVK or MOVZ instruction.
+///
+/// +-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+
+/// | 31 30 29 28 | 27 26 25 24 | 23 22 21 20 | 19 18 17 16 | 15 14 13 12 | 11 10 09 08 | 07 06 05 04 | 03 02 01 00 |
+/// |           1    0  0  1  0    1                                                                                |
+/// | sf op...                       hw... imm16.................................................. rd.............. |
+/// +-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+
+///
+pub struct Mov {
+    /// The register number of the destination register.
+    rd: u8,
+
+    /// The value to move into the register.
+    imm16: u16,
+
+    /// The shift of the value to move.
+    hw: Hw,
+
+    /// Which operation is being performed.
+    op: Op,
+
+    /// Whether or not this instruction is operating on 64-bit operands.
+    sf: Sf
+}
+
+impl Mov {
+    /// MOVK
+    /// https://developer.arm.com/documentation/ddi0602/2022-03/Base-Instructions/MOVK--Move-wide-with-keep-?lang=en
+    pub fn movk(rd: u8, imm16: u16, hw: u8, num_bits: u8) -> Self {
+        Self { rd, imm16, hw: hw.into(), op: Op::MOVK, sf: num_bits.into() }
+    }
+
+    /// MOVZ
+    /// https://developer.arm.com/documentation/ddi0602/2022-03/Base-Instructions/MOVZ--Move-wide-with-zero-?lang=en
+    pub fn movz(rd: u8, imm16: u16, hw: u8, num_bits: u8) -> Self {
+        Self { rd, imm16, hw: hw.into(), op: Op::MOVZ, sf: num_bits.into() }
+    }
+}
+
+/// https://developer.arm.com/documentation/ddi0602/2022-03/Index-by-Encoding/Data-Processing----Immediate?lang=en
+const FAMILY: u32 = 0b1000;
+
+impl From<Mov> for u32 {
+    /// Convert an instruction into a 32-bit value.
+    fn from(inst: Mov) -> Self {
+        0
+        | ((inst.sf as u32) << 31)
+        | ((inst.op as u32) << 29)
+        | (FAMILY << 25)
+        | (0b101 << 23)
+        | ((inst.hw as u32) << 21)
+        | ((inst.imm16 as u32) << 5)
+        | inst.rd as u32
+    }
+}
+
+impl From<Mov> for [u8; 4] {
+    /// Convert an instruction into a 4 byte array.
+    fn from(inst: Mov) -> [u8; 4] {
+        let result: u32 = inst.into();
+        result.to_le_bytes()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_movk_unshifted() {
+        let inst = Mov::movk(0, 123, 0, 64);
+        let result: u32 = inst.into();
+        assert_eq!(0xf2800f60, result);
+    }
+
+    #[test]
+    fn test_movk_shifted_16() {
+        let inst = Mov::movk(0, 123, 16, 64);
+        let result: u32 = inst.into();
+        assert_eq!(0xf2A00f60, result);
+    }
+
+    #[test]
+    fn test_movk_shifted_32() {
+        let inst = Mov::movk(0, 123, 32, 64);
+        let result: u32 = inst.into();
+        assert_eq!(0xf2C00f60, result);
+    }
+
+    #[test]
+    fn test_movk_shifted_48() {
+        let inst = Mov::movk(0, 123, 48, 64);
+        let result: u32 = inst.into();
+        assert_eq!(0xf2e00f60, result);
+    }
+
+    #[test]
+    fn test_movz_unshifted() {
+        let inst = Mov::movz(0, 123, 0, 64);
+        let result: u32 = inst.into();
+        assert_eq!(0xd2800f60, result);
+    }
+
+    #[test]
+    fn test_movz_shifted_16() {
+        let inst = Mov::movz(0, 123, 16, 64);
+        let result: u32 = inst.into();
+        assert_eq!(0xd2a00f60, result);
+    }
+
+    #[test]
+    fn test_movz_shifted_32() {
+        let inst = Mov::movz(0, 123, 32, 64);
+        let result: u32 = inst.into();
+        assert_eq!(0xd2c00f60, result);
+    }
+
+    #[test]
+    fn test_movz_shifted_48() {
+        let inst = Mov::movz(0, 123, 48, 64);
+        let result: u32 = inst.into();
+        assert_eq!(0xd2e00f60, result);
+    }
+}