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//! # B
//!
//! Branch causes a branch to a target address.
#![allow(non_snake_case)]
#![allow(unused)]
use crate::error::Result;
use crate::utils::*;
use super::super::formatter::*;
use super::super::instruction::*;
use super::super::operand::*;
use super::super::consts::*;
use super::super::config::*;
use super::super::decoder::*;
// ---------------------------------------------------------------------------
// Iclass IclassBA1
// ---------------------------------------------------------------------------
/// Type that represents the IclassBA1 instruction class.
pub(crate) struct IclassBA1;
impl IclassBA1 {
/// Tries to decode the instruction in `data`.
pub(crate) fn decode(data: u32, decoder: &mut Decoder) -> Result<Instruction> {
let imm24 = (data >> 0) & 16777215;
let imm24_post = imm24;
let field_25 = (data >> 25) & 1;
let field_25_post = field_25;
let H = (data >> 24) & 1;
let H_post = H;
let field_27 = (data >> 26) & 3;
let field_27_post = field_27;
let cond = (data >> 28) & 15;
let cond_post = cond;
return BA1::decode(data as u32, decoder);
unreachable!()
}
}
/// B A1 encoding.
///
/// # Encoding
///
/// <table style="font-family: courier, monospace">
/// <tr>
/// <td style="border: none">31</td>
/// <td style="border: none">30</td>
/// <td style="border: none">29</td>
/// <td style="border: none">28</td>
/// <td style="border: none">27</td>
/// <td style="border: none">26</td>
/// <td style="border: none">25</td>
/// <td style="border: none">24</td>
/// <td style="border: none">23</td>
/// <td style="border: none">22</td>
/// <td style="border: none">21</td>
/// <td style="border: none">20</td>
/// <td style="border: none">19</td>
/// <td style="border: none">18</td>
/// <td style="border: none">17</td>
/// <td style="border: none">16</td>
/// <td style="border: none">15</td>
/// <td style="border: none">14</td>
/// <td style="border: none">13</td>
/// <td style="border: none">12</td>
/// <td style="border: none">11</td>
/// <td style="border: none">10</td>
/// <td style="border: none">9</td>
/// <td style="border: none">8</td>
/// <td style="border: none">7</td>
/// <td style="border: none">6</td>
/// <td style="border: none">5</td>
/// <td style="border: none">4</td>
/// <td style="border: none">3</td>
/// <td style="border: none">2</td>
/// <td style="border: none">1</td>
/// <td style="border: none">0</td>
/// </tr>
/// <tr>
/// <td style="text-align: center; border-right: none" colspan="4">!= 1111</td>
/// <td style="text-align: center; border-right: none" colspan="1">1</td>
/// <td style="text-align: center; border-left: none" colspan="1">0</td>
/// <td style="text-align: center; border-right: none" colspan="1">1</td>
/// <td style="text-align: center; border-right: none" colspan="1">0</td>
/// <td style="text-align: center" colspan="24">imm24</td>
/// </tr>
/// <tr>
/// <td style="text-align: center; border: none" colspan="4">cond</td>
/// <td style="text-align: center; border: none" colspan="2"></td>
/// <td style="text-align: center; border: none" colspan="1"></td>
/// <td style="text-align: center; border: none" colspan="1">H</td>
/// <td style="text-align: center; border: none" colspan="24"></td>
/// </tr>
/// </table>
pub struct BA1;
impl BA1 {
/// Returns the instruction mnemonic.
pub fn mnemonic(_instr: &Instruction) -> Mnemonic {
Mnemonic::B
}
/// Returns the instruction condition information.
pub fn condition(_instr: &Instruction) -> ConditionalInstruction {
ConditionalInstruction::Condition(0, false, false)
}
/// Returns the instruction size.
pub fn size(instr: &Instruction) -> usize {
4
}
/// Decodes the instruction in `data`.
pub fn decode(data: u32, decoder: &mut Decoder) -> Result<Instruction> {
// Fields are extracted from the input value.
let cond = (data >> 28) & 15;
let cond_post = cond;
let imm24 = (data >> 0) & 16777215;
let imm24_post = imm24;
// Operand values are computed from the base fields.
let cond_post = cond;
let op_0 = MnemonicCondition::decode(cond_post)?;
let imm24_post = ((((imm24) as i32) * 4) << 6) >> 6;
let op_1 = Label::decode((imm24_post).into(), false);
// Instruction creation from the operands.
let mut instr = Instruction::builder(Code::B_A1)
.operand(0, op_0)?
.operand(1, op_1)?
.build();
// For encodings using labels, we check if we are decoding instruction blocks,
// which requires labels to be tracked.
if decoder.block_decoding {
// TODO: handle addition
// The label target is computed from the value stored in the corresponding operand.
let pc = 8 + match instr.op1().as_label()? {
Label::Label(imm) => ((decoder.pc as u64) as i64 + *imm as i64) as u32,
Label::LabelModified(imm) => decoder.pc.wrapping_add(imm.value()),
Label::LabelModifiedNegative(imm) => decoder.pc.wrapping_sub(imm.value()),
_ => unreachable!(),
};
// The label target is added to the decoder hashset and will be used
// to see if labels should be added in the resulting decoded instructions block.
decoder.labels.insert(pc);
// The operand is also replaced by a named label that references the label
// that was added to the hashset.
instr.set_op(1, Label::LabelName(pc as u64))?;
}
Ok(instr)
}
/// Encodes the instruction into `buf`.
pub fn encode(instr: &Instruction, buf: &mut Vec<u8>) -> Result<usize> {
// Retrieve all operand values.
let cond_pre = instr.op0().as_mnemonic_condition()?.encode();
let imm24_pre = instr.op1().as_label()?.encode()?;
// Compute all instruction fields from the operand values.
let cond = (cond_pre & 15);
let imm24_pre = (imm24_pre) / 4;
let imm24 = (imm24_pre & 16777215);
// Add all fields to the base instruction encoding.
let mut instr: u32 = 0b00001010000000000000000000000000;
instr |= (cond & 15) << 28;
instr |= (imm24 & 16777215) << 0;
let bytes = instr.to_le_bytes();
let len = bytes.len();
buf.extend(bytes);
Ok(len)
}
/// Encode an instruction part of an instruction block into `buf`.
pub fn encode_block(instr: &mut Instruction, buf: &mut Vec<u8>, labels: &std::collections::HashMap<u64, u64>) -> Result<usize> {
if let Label::LabelName(label_name) = instr.op1().as_label()? {
if let Some(label_pc) = labels.get(label_name) {
// TODO: handle addition
let pc = *label_pc as i64 - 8 - instr.pc as i64;
instr.set_op(1, Label::decode(pc, false))?;
} else {
// TODO: handle addition
let pc = *label_name as i64 - 8 - instr.pc as i64;
instr.set_op(1, Label::decode(pc, false))?;
}
}
Self::encode(instr, buf)
}
/// Verifies that operand #0 is valid.
pub fn check_op0(instr: &Instruction, op: &Operand) -> Result<()> {
if let Operand::MnemonicCondition(r) = op {
return Ok(())
}
todo!()
}
/// Verifies that operand #1 is valid.
pub fn check_op1(instr: &Instruction, op: &Operand) -> Result<()> {
if let Operand::Label(Label::LabelName(_)) = op {
return Ok(())
}
if let Operand::Label(Label::Label(i)) = op {
if !(-33554432..=33554428).contains(i) {
todo!()
}
return Ok(())
}
todo!()
}
/// Verifies that operand #2 is valid.
pub fn check_op2(instr: &Instruction, op: &Operand) -> Result<()> {
todo!()
}
/// Verifies that operand #3 is valid.
pub fn check_op3(instr: &Instruction, op: &Operand) -> Result<()> {
todo!()
}
/// Verifies that operand #4 is valid.
pub fn check_op4(instr: &Instruction, op: &Operand) -> Result<()> {
todo!()
}
/// Verifies that operand #5 is valid.
pub fn check_op5(instr: &Instruction, op: &Operand) -> Result<()> {
todo!()
}
/// Verifies that operand #6 is valid.
pub fn check_op6(instr: &Instruction, op: &Operand) -> Result<()> {
todo!()
}
/// Formats the instruction.
pub fn format(instr: &Instruction, fmt: &mut impl Formatter, output: &mut impl FormatterOutput, config: &Config) -> Result<()> {
fmt.format_mnemonic(output, &config.global, &config.instructions.b_a1, &instr)?;
fmt.format_operand(output, &config.global, &config.instructions.b_a1, &instr, 0)?;
fmt.format_qualifier(output, &config.global, &config.instructions.b_a1, &instr, FormatterQualifier::Wide, false, false)?;
fmt.format_punctuation(output, &config.global, &config.instructions.b_a1, &instr, FormatterTextKind::Space)?;
fmt.format_operand(output, &config.global, &config.instructions.b_a1, &instr, 1)?;
Ok(())
}
}
/// Type that represents alias identifiers for [`BA1`].
#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Debug, Hash)]
pub enum BA1Aliases {
None,
}
/// Type that represents encoding identifiers for [`BA1`].
#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Debug, Hash)]
pub enum BA1Encodings {
None
}