diff options
Diffstat (limited to 'yjit/src/asm/arm64/inst/call.rs')
-rw-r--r-- | yjit/src/asm/arm64/inst/call.rs | 67 |
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 --- /dev/null +++ b/yjit/src/asm/arm64/inst/call.rs @@ -0,0 +1,67 @@ +/// 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); + } +} |