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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);
}
}
|
