1 files changed, 55 insertions, 0 deletions
diff --git a/yjit/src/asm/arm64/inst/breakpoint.rs b/yjit/src/asm/arm64/inst/breakpoint.rs
new file mode 100644
index 0000000000..be4920ac76
--- /dev/null
+++ b/yjit/src/asm/arm64/inst/breakpoint.rs
@@ -0,0 +1,55 @@
+/// The struct that represents an A64 breakpoint instruction that can be encoded.
+///
+/// +-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+
+/// | 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  1  0  1    0  1  0  0    0  0  1                                                          0    0  0  0  0 |
+/// |                                      imm16..................................................                  |
+/// +-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+
+///
+pub struct Breakpoint {
+    /// The value to be captured by ESR_ELx.ISS
+    imm16: u16
+}
+
+impl Breakpoint {
+    /// BRK
+    /// https://developer.arm.com/documentation/ddi0596/2020-12/Base-Instructions/BRK--Breakpoint-instruction-
+    pub fn brk(imm16: u16) -> Self {
+        Self { imm16 }
+    }
+}
+
+/// https://developer.arm.com/documentation/ddi0602/2022-03/Index-by-Encoding/Branches--Exception-Generating-and-System-instructions?lang=en#control
+const FAMILY: u32 = 0b101;
+
+impl From<Breakpoint> for u32 {
+    /// Convert an instruction into a 32-bit value.
+    fn from(inst: Breakpoint) -> Self {
+        let imm16 = inst.imm16 as u32;
+
+        0
+        | (0b11 << 30)
+        | (FAMILY << 26)
+        | (1 << 21)
+        | (imm16 << 5)
+    }
+}
+
+impl From<Breakpoint> for [u8; 4] {
+    /// Convert an instruction into a 4 byte array.
+    fn from(inst: Breakpoint) -> [u8; 4] {
+        let result: u32 = inst.into();
+        result.to_le_bytes()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_brk() {
+        let result: u32 = Breakpoint::brk(7).into();
+        assert_eq!(0xd42000e0, result);
+    }
+}