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73 lines
2.2 KiB
73 lines
2.2 KiB
use std::convert::TryFrom;
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use sexp::{Atom, Sexp};
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use crate::asm::data::{DataDisp, Rd, RdData, reg, Wr, WrData};
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use crate::asm::data::literal::Label;
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use crate::asm::error::Error;
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use crate::asm::parse::sexp_expect::expect_string_atom;
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/// Parse a label
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pub fn parse_label(name: Option<Sexp>) -> Result<Label, Error> {
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let name = expect_string_atom(name)?;
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Ok(Label::Named(name.trim_start_matches(':').into()))
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}
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/// Parse data disposition (address/value, without the read/write restriction)
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pub fn parse_data_disp(tok: Option<Sexp>) -> Result<DataDisp, Error> {
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let tok = if let Some(tok) = tok {
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tok
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} else {
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return Err(Error::Parse("Expected data disposition token".into()));
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};
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// TODO implement masks
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match &tok {
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Sexp::Atom(Atom::I(val)) => {
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Ok(DataDisp::Immediate(unsafe { std::mem::transmute(*val) }))
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}
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Sexp::Atom(Atom::S(s)) => {
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if s == "_" {
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return Ok(DataDisp::Discard);
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}
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if let Some(reference) = s.strip_prefix('@') {
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Ok(DataDisp::ObjectPtr(reg::parse_reg(reference)?))
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} else if s.starts_with(|c: char| c.is_ascii_digit()) {
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Ok(DataDisp::Immediate(unsafe { std::mem::transmute(parse_i64(s)?) }))
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} else {
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Ok(DataDisp::Register(reg::parse_reg(s)?))
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}
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}
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_ => {
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Err(Error::Parse(format!("bad data disp: {:?}", tok).into()))
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}
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}
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}
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pub fn parse_u64(literal: &str) -> anyhow::Result<u64> {
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if let Some(hex) = literal.strip_prefix("0x") {
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Ok(u64::from_str_radix(hex, 16)?)
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} else if let Some(hex) = literal.strip_prefix("0b") {
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Ok(u64::from_str_radix(hex, 2)?)
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} else {
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Ok(u64::from_str_radix(literal, 10)?)
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}
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}
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pub fn parse_i64(literal: &str) -> anyhow::Result<i64> {
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if let Some(_value) = literal.strip_prefix("-") {
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Ok(-1 * i64::try_from(parse_u64(literal)?)?)
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} else {
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Ok(i64::try_from(parse_u64(literal)?)?)
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}
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}
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pub fn parse_rd(tok: Option<Sexp>) -> anyhow::Result<Rd> {
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Ok(Rd::new(RdData::try_from(parse_data_disp(tok)?)?))
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}
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pub fn parse_wr(tok: Option<Sexp>) -> anyhow::Result<Wr> {
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Ok(Wr::new(WrData::try_from(parse_data_disp(tok)?)?))
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}
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