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-rw-r--r--yjit/src/asm/arm64/inst/call.rs67
1 files changed, 67 insertions, 0 deletions
diff --git a/yjit/src/asm/arm64/inst/call.rs b/yjit/src/asm/arm64/inst/call.rs
new file mode 100644
index 0000000000..6f23acf9f5
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+++ b/yjit/src/asm/arm64/inst/call.rs
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+/// The struct that represents an A64 branch with link 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 0 0 1 0 1 |
+/// | imm26.................................................................................... |
+/// +-------------+-------------+-------------+-------------+-------------+-------------+-------------+-------------+
+///
+pub struct Call {
+ /// The PC-relative offset to jump to (which will be multiplied by 4).
+ imm26: i32
+}
+
+impl Call {
+ /// BL
+ /// https://developer.arm.com/documentation/ddi0596/2021-12/Base-Instructions/BL--Branch-with-Link-?lang=en
+ pub fn bl(imm26: i32) -> Self {
+ Self { imm26 }
+ }
+}
+
+/// https://developer.arm.com/documentation/ddi0602/2022-03/Index-by-Encoding/Branches--Exception-Generating-and-System-instructions?lang=en
+const FAMILY: u32 = 0b101;
+
+impl From<Call> for u32 {
+ /// Convert an instruction into a 32-bit value.
+ fn from(inst: Call) -> Self {
+ let imm26 = (inst.imm26 as u32) & ((1 << 26) - 1);
+
+ 0
+ | (1 << 31)
+ | (FAMILY << 26)
+ | imm26
+ }
+}
+
+impl From<Call> for [u8; 4] {
+ /// Convert an instruction into a 4 byte array.
+ fn from(inst: Call) -> [u8; 4] {
+ let result: u32 = inst.into();
+ result.to_le_bytes()
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn test_bl() {
+ let result: u32 = Call::bl(0).into();
+ assert_eq!(0x94000000, result);
+ }
+
+ #[test]
+ fn test_bl_positive() {
+ let result: u32 = Call::bl(256).into();
+ assert_eq!(0x94000100, result);
+ }
+
+ #[test]
+ fn test_bl_negative() {
+ let result: u32 = Call::bl(-256).into();
+ assert_eq!(0x97ffff00, result);
+ }
+}