1 files changed, 143 insertions, 0 deletions
diff --git a/yjit/src/asm/arm64/inst/data_imm.rs b/yjit/src/asm/arm64/inst/data_imm.rs
new file mode 100644
index 0000000000..b474b00a52
--- /dev/null
+++ b/yjit/src/asm/arm64/inst/data_imm.rs
@@ -0,0 +1,143 @@
+use super::super::arg::{Sf, ShiftedImmediate};
+
+/// The operation being performed by this instruction.
+enum Op {
+    Add = 0b0,
+    Sub = 0b1
+}
+
+// Whether or not to update the flags when this instruction is performed.
+enum S {
+    LeaveFlags = 0b0,
+    UpdateFlags = 0b1
+}
+
+/// The struct that represents an A64 data processing -- immediate instruction
+/// that can be encoded.
+///
+/// Add/subtract (immediate)
+/// +-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+
+/// | 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  0  1    0                                                                                |
+/// | sf op  S                       sh imm12.................................... rn.............. rd.............. |
+/// +-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+
+///
+pub struct DataImm {
+    /// The register number of the destination register.
+    rd: u8,
+
+    /// The register number of the first operand register.
+    rn: u8,
+
+    /// How much to shift the immediate by.
+    imm: ShiftedImmediate,
+
+    /// Whether or not to update the flags when this instruction is performed.
+    s: S,
+
+    /// The opcode for this instruction.
+    op: Op,
+
+    /// Whether or not this instruction is operating on 64-bit operands.
+    sf: Sf
+}
+
+impl DataImm {
+    /// ADD (immediate)
+    /// https://developer.arm.com/documentation/ddi0596/2021-12/Base-Instructions/ADD--immediate---Add--immediate--?lang=en
+    pub fn add(rd: u8, rn: u8, imm: ShiftedImmediate, num_bits: u8) -> Self {
+        Self { rd, rn, imm, s: S::LeaveFlags, op: Op::Add, sf: num_bits.into() }
+    }
+
+    /// ADDS (immediate, set flags)
+    /// https://developer.arm.com/documentation/ddi0596/2021-12/Base-Instructions/ADDS--immediate---Add--immediate---setting-flags-?lang=en
+    pub fn adds(rd: u8, rn: u8, imm: ShiftedImmediate, num_bits: u8) -> Self {
+        Self { rd, rn, imm, s: S::UpdateFlags, op: Op::Add, sf: num_bits.into() }
+    }
+
+    /// CMP (immediate)
+    /// https://developer.arm.com/documentation/ddi0596/2021-12/Base-Instructions/CMP--immediate---Compare--immediate---an-alias-of-SUBS--immediate--?lang=en
+    pub fn cmp(rn: u8, imm: ShiftedImmediate, num_bits: u8) -> Self {
+        Self::subs(31, rn, imm, num_bits)
+    }
+
+    /// SUB (immediate)
+    /// https://developer.arm.com/documentation/ddi0596/2021-12/Base-Instructions/SUB--immediate---Subtract--immediate--?lang=en
+    pub fn sub(rd: u8, rn: u8, imm: ShiftedImmediate, num_bits: u8) -> Self {
+        Self { rd, rn, imm, s: S::LeaveFlags, op: Op::Sub, sf: num_bits.into() }
+    }
+
+    /// SUBS (immediate, set flags)
+    /// https://developer.arm.com/documentation/ddi0596/2021-12/Base-Instructions/SUBS--immediate---Subtract--immediate---setting-flags-?lang=en
+    pub fn subs(rd: u8, rn: u8, imm: ShiftedImmediate, num_bits: u8) -> Self {
+        Self { rd, rn, imm, s: S::UpdateFlags, op: Op::Sub, 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<DataImm> for u32 {
+    /// Convert an instruction into a 32-bit value.
+    fn from(inst: DataImm) -> Self {
+        let imm: u32 = inst.imm.into();
+
+        0
+        | ((inst.sf as u32) << 31)
+        | ((inst.op as u32) << 30)
+        | ((inst.s as u32) << 29)
+        | (FAMILY << 25)
+        | (1 << 24)
+        | (imm << 10)
+        | ((inst.rn as u32) << 5)
+        | inst.rd as u32
+    }
+}
+
+impl From<DataImm> for [u8; 4] {
+    /// Convert an instruction into a 4 byte array.
+    fn from(inst: DataImm) -> [u8; 4] {
+        let result: u32 = inst.into();
+        result.to_le_bytes()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_add() {
+        let inst = DataImm::add(0, 1, 7.try_into().unwrap(), 64);
+        let result: u32 = inst.into();
+        assert_eq!(0x91001c20, result);
+    }
+
+    #[test]
+    fn test_adds() {
+        let inst = DataImm::adds(0, 1, 7.try_into().unwrap(), 64);
+        let result: u32 = inst.into();
+        assert_eq!(0xb1001c20, result);
+    }
+
+    #[test]
+    fn test_cmp() {
+        let inst = DataImm::cmp(0, 7.try_into().unwrap(), 64);
+        let result: u32 = inst.into();
+        assert_eq!(0xf1001c1f, result);
+    }
+
+    #[test]
+    fn test_sub() {
+        let inst = DataImm::sub(0, 1, 7.try_into().unwrap(), 64);
+        let result: u32 = inst.into();
+        assert_eq!(0xd1001c20, result);
+    }
+
+    #[test]
+    fn test_subs() {
+        let inst = DataImm::subs(0, 1, 7.try_into().unwrap(), 64);
+        let result: u32 = inst.into();
+        assert_eq!(0xf1001c20, result);
+    }
+}