dynasm\arch\riscv/compiler.rs
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use super::Context;
use super::riscvdata::{Template, Command, Relocation, ROUNDMODE_MAP, FENCESPEC_MAP, CSR_MAP, FP_IMM_IDENT_MAP, FP_IMM_VALUE_MAP};
use super::ast::{MatchData, FlatArg, RegListFlat, Register};
use syn::spanned::Spanned;
use quote::{quote, quote_spanned};
use proc_macro2::{TokenStream, Span, Literal};
use proc_macro_error2::emit_error;
use crate::parse_helpers::{as_signed_number, as_ident, as_float};
use crate::common::{Stmt, Size, delimited, bitmask, bitmask64};
/// Compile a single instruction. Input is taken from `data`, containing both the arguments
/// and the encoding template and commands.
/// Output is written to ctx.state
/// Errors can be emitted to either the whole instruction span (by returning Err(Some(errormsg)))
/// or emited specifically using emit_error! and returning Err(None)
pub(super) fn compile_instruction(ctx: &mut Context, data: MatchData) -> Result<(), Option<String>> {
// argument cursor
let mut cursor = 0usize;
// All static bitfields (compile-time constant) will be encoded into this map of (offset, bitfield)
let mut statics = Vec::new();
// All dynamic bitfields (run-time determined) will be encoded into this map of (offset, TokenStream)
let mut dynamics = Vec::new();
// Any relocation will be encoded in this list
let mut relocations = Vec::new();
for (i, command) in data.data.commands.iter().enumerate() {
// meta commands
match *command {
Command::Repeat => {
cursor -= 1;
continue;
},
Command::Next => {
cursor += 1;
continue;
},
_ => ()
}
let arg = data.args.get(cursor).expect("Invalid encoding data, tried to process more arguments than given");
match *arg {
FlatArg::Register { span, reg: Register::Static(id) } => {
let mut code = id.code();
let offset = match *command {
Command::R(offset) => offset,
Command::Reven(offset) => {
if code & 0x1 != 0 {
emit_error!(span, "This register must be even numbered");
return Err(None);
}
offset
},
Command::Rno0(offset) => {
if code == 0 {
emit_error!(span, "This register must not be x0");
return Err(None);
}
offset
},
Command::Rno02(offset) => {
if code == 0 || code == 2 {
emit_error!(span, "This register must not be x0 or x2");
return Err(None);
}
offset
},
Command::Rpop(offset) => {
if code < 8 || code > 15 {
emit_error!(span, "This register must be one of x8-x15");
return Err(None);
}
code &= 7;
offset
},
Command::Rpops(offset) => {
if ((1 << code) & 0x00_FC_03_00) == 0 {
emit_error!(span, "This register must be one of s0-s7 (x8, x9, x18-x23");
return Err(None);
}
code &= 7;
offset
},
Command::Rpops2(offset) => {
match data.args.get(cursor - 1) {
Some(FlatArg::Register { reg: Register::Static(id2), .. } ) => {
if *id2 == id {
emit_error!(span, "This register cannot be identical to the previous argument");
return Err(None);
}
},
Some(FlatArg::Register { reg: Register::Dynamic(_, ref expr), .. }) => {
dynamics.push((0, quote_spanned!{ span=>
{
let _dyn_reg: u8 = #expr;
if _dyn_reg == #code {
::dynasmrt::riscv::invalid_register(#code);
}
0u32
}
}));
},
_ => panic!("Invalid encoding data, expected a register before")
}
if ((1 << code) & 0x00_FC_03_00) == 0 {
emit_error!(span, "This register must be one of s0-s7 (x8, x9, x18-x23");
return Err(None);
}
code &= 7;
offset
},
_ => panic!("Invalid argument processor")
};
statics.push((offset, u32::from(code)));
},
FlatArg::Register { span, reg: Register::Dynamic(_, ref expr) } => match *command {
Command::R(offset) => {
dynamics.push((offset, quote_spanned!{ span=>
((#expr & 0x1F) as u32)
}));
},
Command::Reven(offset) => {
let invalid_reg_mask: u8 = if ctx.target.is_embedded() { 0xF0 } else { 0xE0 };
dynamics.push((offset, quote_spanned!{ span=>
{
let _dyn_reg: u8 = #expr;
if _dyn_reg & 0x1 != 0x0 || (_dyn_reg & #invalid_reg_mask) != 0 {
::dynasmrt::riscv::invalid_register(_dyn_reg);
}
(_dyn_reg & 0x1E) as u32
}
}));
},
Command::Rno0(offset) => {
let invalid_reg_mask: u8 = if ctx.target.is_embedded() { 0xF0 } else { 0xE0 };
dynamics.push((offset, quote_spanned!{ span=>
{
let _dyn_reg: u8 = #expr;
if _dyn_reg == 0x0 || (_dyn_reg & #invalid_reg_mask) != 0 {
::dynasmrt::riscv::invalid_register(_dyn_reg);
}
(_dyn_reg & 0x1F) as u32
}
}));
},
Command::Rno02(offset) => {
let invalid_reg_mask: u8 = if ctx.target.is_embedded() { 0xF0 } else { 0xE0 };
dynamics.push((offset, quote_spanned!{ span=>
{
let _dyn_reg: u8 = #expr;
if _dyn_reg == 0x0 || _dyn_reg == 0x2 || (_dyn_reg & #invalid_reg_mask) != 0 {
::dynasmrt::riscv::invalid_register(_dyn_reg);
}
(_dyn_reg & 0x1F) as u32
}
}));
},
Command::Rpop(offset) => {
let invalid_reg_mask: u8 = if ctx.target.is_embedded() { 0xF0 } else { 0xE0 };
dynamics.push((offset, quote_spanned!{ span=>
{
let _dyn_reg: u8 = #expr;
if _dyn_reg & 0x18 != 0x8 || (_dyn_reg & #invalid_reg_mask) != 0 {
::dynasmrt::riscv::invalid_register(_dyn_reg);
}
(_dyn_reg & 0x7) as u32
}
}));
},
Command::Rpops(offset) => {
let invalid_reg_mask: u8 = if ctx.target.is_embedded() { 0xF0 } else { 0xE0 };
dynamics.push((offset, quote_spanned!{ span=>
{
let _dyn_reg: u8 = #expr;
if (1u32 << (_dyn_reg & 0x1F)) & 0x00_FC_03_00 == 0 || (_dyn_reg & #invalid_reg_mask) != 0 {
::dynasmrt::riscv::invalid_register(_dyn_reg);
}
(_dyn_reg & 0x7) as u32
}
}));
},
Command::Rpops2(offset) => match data.args.get(cursor - 1) {
Some(FlatArg::Register { reg: Register::Static(id2), .. } ) => {
let code: u8 = id2.code();
let invalid_reg_mask: u8 = if ctx.target.is_embedded() { 0xF0 } else { 0xE0 };
dynamics.push((offset, quote_spanned!{ span=>
{
let _dyn_reg: u8 = #expr;
if (_dyn_reg == #code) || ((1u32 << (_dyn_reg & 0x1F)) & 0x00_FC_03_00 == 0) || (_dyn_reg & #invalid_reg_mask) != 0 {
::dynasmrt::riscv::invalid_register(_dyn_reg);
}
(_dyn_reg & 0x7) as u32
}
}));
},
Some(FlatArg::Register { reg: Register::Dynamic(_, ref expr2), .. }) => {
let invalid_reg_mask: u8 = if ctx.target.is_embedded() { 0xF0 } else { 0xE0 };
dynamics.push((offset, quote_spanned!{ span=>
{
let _dyn_reg: u8 = #expr;
let _dyn_reg_prev: u8 = #expr2;
if (_dyn_reg == _dyn_reg_prev) || ((1u32 << (_dyn_reg & 0x1F)) & 0x00_FC_03_00 == 0) || (_dyn_reg & #invalid_reg_mask) != 0 {
::dynasmrt::riscv::invalid_register(_dyn_reg);
}
(_dyn_reg & 0x7) as u32
}
}));
},
_ => panic!("Invalid encoding data, expected a register before")
},
_ => panic!("Invalid argument processor")
},
FlatArg::RegisterList { span, ref count } => match *command {
Command::Rlist(offset) => match count {
RegListFlat::Static(c) => {
statics.push((offset, u32::from(*c)));
},
RegListFlat::Dynamic(expr) => {
if let Some(static_value) = as_signed_number(expr) {
if static_value < 0 || (static_value > 10 && static_value != 12) {
emit_error!(expr, "Impossible register list");
return Err(None);
}
let c = if static_value == 12 {
15
} else {
(static_value + 4) as u32
};
statics.push((offset, c));
} else {
// okay, so we're given an expression here, with legal input values
// being 0-10 and 12, which should be mapped to 4-14 and 15
// note: this isn't quite the right register error
dynamics.push((offset, quote_spanned!{ span=>
{
let _dyn_reg: u32 = #expr;
if _dyn_reg == 11 || _dyn_reg > 12 {
::dynasmrt::riscv::invalid_register(_dyn_reg as u8);
}
(_dyn_reg + if (_dyn_reg == 12) { 3 } else { 4 }) & 0xF
}
}));
}
}
},
_ => panic!("Invalid argument processor")
},
FlatArg::Default => match *command {
// Default is only emitted for a RefOffset where no offset was provided, i.e. it is 0
// This practically means we just don't have to encode anything.
Command::UImm(_, _)
| Command::SImm(_, _)
| Command::BitRange(_, _, _)
| Command::Next => (),
_ => panic!("Invalid argument processor")
},
FlatArg::Immediate { ref value } => match *command {
// integer verification commands
Command::UImm(bits, scaling) => {
let span = value.span();
let range: u32 = bitmask(bits);
let mut imm_encoder = ImmediateEncoder::new(value);
imm_encoder.gather_fields(data.data.commands, i + 1, &mut statics);
match imm_encoder.static_value {
Some(static_value) => {
static_range_check(static_value, 0, range, scaling, span)?;
},
None => {
let check = if scaling == 0 {
quote_spanned!{ span =>
_dyn_imm > #range
}
} else {
let zeromask: u32 = bitmask(scaling);
quote_spanned!{ span =>
_dyn_imm > #range || _dyn_imm & #zeromask != 0u32
}
};
imm_encoder.emit_dynamic(false, false, check, &mut dynamics);
}
}
},
Command::SImm(bits, scaling) => {
let span = value.span();
let range = bitmask(bits);
let min: i32 = (-1) << (bits - 1);
let mut imm_encoder = ImmediateEncoder::new(value);
imm_encoder.gather_fields(data.data.commands, i + 1, &mut statics);
match imm_encoder.static_value {
Some(static_value) => {
static_range_check(static_value, min, range, scaling, span)?;
},
None => {
let check = if scaling == 0 {
quote_spanned!{ span =>
_dyn_imm.wrapping_sub(#min) as u32 > #range
}
} else {
let zeromask = bitmask(scaling) as i32;
quote_spanned!{ span =>
_dyn_imm.wrapping_sub(#min) as u32 > #range || _dyn_imm & #zeromask != 0i32
}
};
imm_encoder.emit_dynamic(true, false, check, &mut dynamics);
}
}
},
Command::BigImm(bits) => {
let span = value.span();
let range = bitmask64(bits);
let min: i64 = (-1) << (bits - 1);
let mut imm_encoder = ImmediateEncoder::new(value);
imm_encoder.gather_fields(data.data.commands, i + 1, &mut statics);
match imm_encoder.static_value {
Some(static_value) => {
if static_value < min {
emit_error!(span, "Immediate too low");
return Err(None);
}
if static_value.wrapping_sub(min) as u64 > range {
emit_error!(span, "Immediate too high");
return Err(None);
}
},
None => {
let check = quote_spanned!{ span =>
_dyn_imm.wrapping_sub(#min) as u64 > #range
};
imm_encoder.emit_dynamic(true, true, check, &mut dynamics);
}
}
},
Command::UImmNo0(bits, scaling) => {
let span = value.span();
let range = bitmask(bits);
let mut imm_encoder = ImmediateEncoder::new(value);
imm_encoder.gather_fields(data.data.commands, i + 1, &mut statics);
match imm_encoder.static_value {
Some(static_value) => {
static_range_check(static_value, 0, range, scaling, span)?;
if static_value == 0 {
emit_error!(span, "Immediate cannot be zero");
return Err(None);
}
},
None => {
let check = if scaling == 0 {
quote_spanned!{ span =>
_dyn_imm > #range || _dyn_imm == 0u32
}
} else {
let zeromask: u32 = bitmask(scaling);
quote_spanned!{ span =>
_dyn_imm > #range || _dyn_imm & #zeromask != 0u32 || _dyn_imm == 0u32
}
};
imm_encoder.emit_dynamic(false, false, check, &mut dynamics);
},
}
},
Command::SImmNo0(bits, scaling) => {
let span = value.span();
let range = bitmask(bits);
let min: i32 = (-1) << (bits - 1);
let mut imm_encoder = ImmediateEncoder::new(value);
imm_encoder.gather_fields(data.data.commands, i + 1, &mut statics);
match imm_encoder.static_value {
Some(static_value) => {
static_range_check(static_value, min, range, scaling, span)?;
if static_value == 0 {
emit_error!(span, "Immediate cannot be zero");
return Err(None);
}
},
None => {
let check = if scaling == 0 {
quote_spanned!{ span =>
_dyn_imm.wrapping_sub(#min) as u32 > #range || _dyn_imm == 0i32
}
} else {
let zeromask = bitmask(scaling) as i32;
quote_spanned!{ span =>
_dyn_imm.wrapping_sub(#min) as u32 > #range || _dyn_imm & #zeromask != 0i32 || _dyn_imm == 0i32
}
};
imm_encoder.emit_dynamic(true, false, check, &mut dynamics);
}
}
},
Command::UImmOdd(bits, scaling) => {
let span = value.span();
let range = bitmask(bits);
let zeromask: u32 = bitmask(scaling);
let mut imm_encoder = ImmediateEncoder::new(value);
imm_encoder.gather_fields(data.data.commands, i + 1, &mut statics);
match imm_encoder.static_value {
Some(static_value) => {
let biased = static_range_check(static_value, 0, range, 0, span)?;
if biased & zeromask != zeromask {
emit_error!(span, "Unrepresentable immediate");
return Err(None);
}
},
None => {
let check = if scaling == 0 {
quote_spanned!{ span =>
_dyn_imm > #range
}
} else {
quote_spanned!{ span =>
_dyn_imm > #range || _dyn_imm & #zeromask != #zeromask
}
};
imm_encoder.emit_dynamic(false, false, check, &mut dynamics);
}
}
},
Command::UImmRange(min, max) => {
let span = value.span();
let min = u32::from(min);
let max = u32::from(max);
let mut imm_encoder = ImmediateEncoder::new(value);
imm_encoder.gather_fields(data.data.commands, i + 1, &mut statics);
match imm_encoder.static_value {
Some(static_value) => {
if static_value < i64::from(min) {
emit_error!(span, "Immediate too low");
return Err(None);
}
if static_value > i64::from(max) {
emit_error!(span, "Immediate too high");
return Err(None);
}
},
None => {
let check = quote_spanned!{ span=>
_dyn_imm < #min || _dyn_imm > #max
};
imm_encoder.emit_dynamic(false, false, check, &mut dynamics);
}
}
},
// integer encoding commands
Command::BitRange(offset, bits, scaling) => (),
Command::RBitRange(offset, bits, scaling) => (),
// offsets can accept immediates too
Command::Offset(relocation_type) => {
let bits;
let scaling;
let commands: &'static [Command];
// equivalent bitrange encodings for offsets
match relocation_type {
// 12 bits, 2-bit scaled. Equivalent to
Relocation::B => {
bits = 12;
scaling = 1;
commands = &[
Command::BitRange(31, 1, 12),
Command::BitRange(25, 6, 5),
Command::BitRange(8, 4, 1),
Command::BitRange(7, 1, 11),
Command::Next
];
},
// 20 bits, 2-bit scaled
Relocation::J => {
bits = 20;
scaling = 1;
commands = &[
Command::BitRange(31, 1, 20),
Command::BitRange(21, 10, 1),
Command::BitRange(20, 1, 11),
Command::BitRange(12, 8, 12),
Command::Next
];
},
// 9 bits, 2-bit scaled
Relocation::BC => {
bits = 9;
scaling = 1;
commands = &[
Command::BitRange(12, 1, 8),
Command::BitRange(10, 2, 3),
Command::BitRange(5, 2, 6),
Command::BitRange(3, 2, 1),
Command::BitRange(2, 1, 5),
Command::Next
];
},
// 12 bits, 2-bit scaled
Relocation::JC => {
bits = 12;
scaling = 1;
commands = &[
Command::BitRange(12, 1, 11),
Command::BitRange(11, 1, 4),
Command::BitRange(9, 2, 8),
Command::BitRange(8, 1, 10),
Command::BitRange(7, 1, 6),
Command::BitRange(6, 1, 7),
Command::BitRange(3, 3, 1),
Command::BitRange(2, 1, 5),
Command::Next
]; // why
},
// 32 bits, 12-bit scaled, offset by 0x800
Relocation::HI20 => {
bits = 32;
scaling = 0;
commands = &[
Command::RBitRange(12, 20, 12),
Command::Next
];
},
// 12 bits, no scaling
Relocation::LO12 => {
bits = 12;
scaling = 0;
commands = &[
Command::BitRange(20, 12, 0),
Command::Next
];
},
// 12 bits, no scaling
Relocation::LO12S => {
bits = 12;
scaling = 0;
commands = &[
Command::BitRange(7, 5, 0),
Command::BitRange(25, 7, 5),
Command::Next
];
},
// 32 bits, no scaling, offset by 0x800
Relocation::SPLIT32 => {
bits = 32;
scaling = 0;
commands = &[
Command::RBitRange(12, 20, 12),
Command::BitRange(20+32, 12, 0),
Command::Next
];
},
// 32 bits, no scaling, offset by 0x800
Relocation::SPLIT32S => {
bits = 32;
scaling = 0;
commands = &[
Command::RBitRange(12, 20, 12),
Command::BitRange(7+32, 5, 0),
Command::BitRange(25+32, 7, 5),
Command::Next
];
},
Relocation::LITERAL8
| Relocation::LITERAL16
| Relocation::LITERAL32
| Relocation::LITERAL64 => panic!("Literal relocation in instruction"),
}
let span = value.span();
let mut range = bitmask(bits);
let min: i32 = (-1) << (bits - 1);
// special case: the 32-bit AUIPC-based offsets don't actually
// range from -0x8000_0000 to 0x7FFF_FFFF on RV64 due to how
// sign extension interacts between them, they range from
// -0x8000_0800 to 0x7FFF_F7FF. But on RV32 they do span
// from -0x8000_0000 to 0x7FFF_FFFF.
// neither of these limits will ever occur in practical code,
// so for sanity's sake we just clamp to between -0x8000_0000 and
// 0x7FFF_F7FF
if bits == 32 {
range = 0xFFFF_F7FF;
}
let mut imm_encoder = ImmediateEncoder::new(value);
imm_encoder.gather_fields(commands, 0, &mut statics);
match imm_encoder.static_value {
Some(static_value) => {
static_range_check(static_value, min, range, scaling, span)?;
},
None => {
let check = if scaling == 0 {
quote_spanned!{ span =>
_dyn_imm.wrapping_sub(#min) as u32 > #range
}
} else {
let zeromask = bitmask(scaling) as i32;
quote_spanned!{ span =>
_dyn_imm.wrapping_sub(#min) as u32 > #range || _dyn_imm & #zeromask != 0i32
}
};
imm_encoder.emit_dynamic(true, false, check, &mut dynamics);
}
}
},
// Non-integer immediate commands
Command::RoundingMode(offset) => {
let name = as_ident(value).expect("bad command data").to_string();
if let Some(&bits) = ROUNDMODE_MAP.get(&&*name) {
statics.push((offset, u32::from(bits)));
} else {
emit_error!(value, "Unknown literal");
return Err(None);
}
},
Command::FenceSpec(offset) => {
let name = as_ident(value).expect("bad command data").to_string();
if let Some(&bits) = FENCESPEC_MAP.get(&&*name) {
statics.push((offset, u32::from(bits)));
} else {
emit_error!(value, "Unknown literal");
return Err(None);
}
},
Command::Csr(offset) => 'csr: {
// Csr is a bit special as it allows both immediates and names
// because we cannot differentiate from those earlier, we handle that here.
if let Some(name) = as_ident(value) {
let name = name.to_string();
if let Some(&bits) = CSR_MAP.get(&&*name) {
statics.push((offset, u32::from(bits)));
break 'csr;
}
}
let span = value.span();
let range = 0xFFF;
let commands = &[
Command::BitRange(offset, 12, 0),
Command::Next
];
let mut imm_encoder = ImmediateEncoder::new(value);
imm_encoder.gather_fields(commands, 0, &mut statics);
match imm_encoder.static_value {
Some(static_value) => {
static_range_check(static_value, 0, range, 0, span)?;
},
None => {
let check = quote_spanned!{ span =>
_dyn_imm > #range
};
imm_encoder.emit_dynamic(false, false, check, &mut dynamics);
}
}
},
Command::FloatingPointImmediate(offset) => 'fpimm: {
// this one has several special cases, and is very hard to do at runtime
// firstly, min, inf and nan are not actually values, but idents
// (min depends on what kind of floating point register the instruction targets)
// next to that, we need to parse 29 floating point values
if let Some(name) = as_ident(value) {
let name = name.to_string();
if let Some(&bits) = FP_IMM_IDENT_MAP.get(&&*name) {
statics.push((offset, u32::from(bits)));
break 'fpimm;
}
}
if let Some(value) = as_float(value) {
let value = value as f32;
if let Some(&(_, bits)) = FP_IMM_VALUE_MAP.iter().find(|(val, bits)| val == &value) {
statics.push((offset, u32::from(bits)));
break 'fpimm;
}
}
emit_error!(value, "Invalid floating point immediate.");
return Err(None);
},
Command::SPImm(offset, negated) => 'spimm: {
// the value we need to encode here depends on the count of registers in the
// register list, and depends on the target architecture as well.
let count = match data.args.get(cursor - 1) {
Some(FlatArg::RegisterList { count, .. }) => count,
_ => panic!("Invalid encoding data, expected a register list before")
};
let span = value.span();
// either statically encode it, or return an expression for the register list bias
let bias_expr = match count {
RegListFlat::Static(code) => {
let code = if *code == 15 {16} else {*code};
let bias = if ctx.target.is_32_bit() {
i32::from(code / 4 * 16)
} else {
i32::from(code / 2 * 16 - 16)
};
if let Some(mut static_value) = as_signed_number(value) {
// statically encode everything
if negated {
static_value = static_value.saturating_neg();
}
let bits = static_range_check(static_value, bias, 48, 4, span)? >> 4;
statics.push((offset, bits));
break 'spimm;
} else {
quote_spanned!{ span=>
let _reglist_bias: i32 = #bias;
}
}
},
RegListFlat::Dynamic(expr) => {
if let Some(mut static_value) = as_signed_number(value) {
// just some sanity checks at compile time
if negated {
static_value = static_value.saturating_neg();
}
if ctx.target.is_32_bit() {
static_range_check(static_value, 16, 96, 4, span)?;
} else {
static_range_check(static_value, 16, 144, 4, span)?;
}
}
if ctx.target.is_32_bit() {
quote_spanned!{ span=>
let _reglist_expr: u8 = #expr;
let _reglist_bias: i32 = (_reglist_expr as i32) / 4 * 16 + 16;
}
} else {
quote_spanned!{ span=>
let _reglist_expr: u8 = #expr;
let _reglist_bias: i32 = (_reglist_expr as i32) / 2 * 16 + 16;
}
}
}
};
let imm_expr = if negated {
quote_spanned!{ span=>
let _dyn_imm: i32 = -#value;
}
} else {
quote_spanned!{ span=>
let _dyn_imm: i32 = #value;
}
};
dynamics.push((offset, quote_spanned!{ span=>
{
#imm_expr
#bias_expr
if (_dyn_imm < _reglist_bias) || ((_dyn_imm - _reglist_bias) > 48) || ((_dyn_imm & 15) != 0) {
::dynasmrt::riscv::immediate_out_of_range_signed_32(_dyn_imm);
}
(_dyn_imm - _reglist_bias) as u32 >> 4
}
}));
},
_ => panic!("Invalid argument processor")
},
FlatArg::JumpTarget { ref jump } => match *command {
Command::Offset( relocation ) => {
// encode the complete relocation. Always starts at the begin of the instruction(s), and also relative to that
let stmt = jump.clone().encode(relocation.size(), relocation.size(), &[relocation.to_id()]);
relocations.push(stmt);
},
_ => panic!("Invalid argument processor")
}
}
// figure out how far the cursor has to be advanced.
match *command {
Command::UImm(_, _)
| Command::SImm(_, _)
| Command::BigImm(_)
| Command::UImmNo0(_, _)
| Command::SImmNo0(_, _)
| Command::UImmOdd(_, _)
| Command::UImmRange(_, _)
| Command::BitRange(_, _, _)
| Command::RBitRange(_, _, _) => (),
_ => cursor += 1
}
}
// sanity
if cursor != data.args.len() {
panic!("Not enough command processors");
}
let mut templates = [0u32; 8];
let mut exprs = [None, None, None, None, None, None, None, None];
// for convenience sake we operate in 32 bits width, even for compressed instructions
match data.data.template {
Template::Compressed(val) => templates[0] = u32::from(val),
Template::Single(val) => templates[0] = val,
Template::Double(val1, val2) => {
templates[0] = val1;
templates[1] = val2;
},
Template::Many(values) => {
templates[ .. values.len()].copy_from_slice(values);
}
};
// apply all statics to templates
for (offset, value) in statics {
templates[(offset >> 5) as usize] |= value << (offset & 0x1F);
}
// and process all dynamics
for (offset, expr) in dynamics {
let index = usize::from(offset >> 5);
let offset = offset & 0x1F;
exprs[index] = match exprs[index].take() {
Some(prev_expr) => {
Some(if offset == 0 {
quote!{ #prev_expr | #expr }
} else {
quote!{ #prev_expr | (#expr << #offset) }
})
},
None => {
let bits = templates[index];
Some(if offset == 0 {
quote!{ #bits | #expr }
} else {
quote!{ #bits | (#expr << #offset) }
})
}
}
}
match data.data.template {
Template::Compressed(_) => if let Some(d) = exprs[0].take() {
let res = quote!{ (#d) as u16 };
ctx.state.stmts.push(Stmt::ExprUnsigned(delimited(res), Size::B_2));
} else {
ctx.state.stmts.push(Stmt::Const(u64::from(templates[0] & 0xFFFF), Size::B_2));
},
Template::Single(_) => if let Some(d) = exprs[0].take() {
ctx.state.stmts.push(Stmt::ExprUnsigned(delimited(d), Size::B_4));
} else {
ctx.state.stmts.push(Stmt::Const(u64::from(templates[0]), Size::B_4));
},
Template::Double(_, _) => {
for i in 0 .. 2 {
if let Some(d) = exprs[i].take() {
ctx.state.stmts.push(Stmt::ExprUnsigned(delimited(d), Size::B_4));
} else {
ctx.state.stmts.push(Stmt::Const(u64::from(templates[i]), Size::B_4));
}
}
},
Template::Many(c) => {
for i in 0 .. c.len() {
if let Some(d) = exprs[i].take() {
ctx.state.stmts.push(Stmt::ExprUnsigned(delimited(d), Size::B_4));
} else {
ctx.state.stmts.push(Stmt::Const(u64::from(templates[i]), Size::B_4));
}
}
}
}
ctx.state.stmts.extend(relocations);
Ok(())
}
/// Handles the encoding of immediates in a somewhat efficient fashion.
struct ImmediateEncoder<'a> {
pub dynamic_value: &'a syn::Expr,
pub static_value: Option<i64>,
pub encodes: Vec<(u8, TokenStream)>, // encoding_offset, expression
pub span: Span
}
impl<'a> ImmediateEncoder<'a> {
pub fn new(dynamic_value: &syn::Expr) -> ImmediateEncoder {
#![allow(unexpected_cfgs)]
let static_value;
// this allows turning off static checks for testing purposes
#[cfg(not(disable_static_checks="1"))]
{
static_value = as_signed_number(dynamic_value);
}
#[cfg(disable_static_checks="1")]
{
static_value = None;
}
let span = dynamic_value.span();
ImmediateEncoder {
dynamic_value,
static_value,
encodes: Vec::new(),
span
}
}
pub fn gather_fields(&mut self, commands: &[Command], mut index: usize, statics: &mut Vec<(u8, u32)>) {
loop {
match commands.get(index) {
Some(&Command::BitRange(offset, bits, scaling)) => {
let mask = bitmask(bits);
if let Some(v) = self.static_value {
let slice = (v >> scaling) as u32 & mask;
statics.push((offset, slice));
} else {
self.encodes.push((offset, quote_spanned!{ self.span=>
((_dyn_imm >> #scaling) as u32 & #mask)
}));
}
},
Some(&Command::RBitRange(offset, bits, scaling)) => {
let mask = bitmask(bits);
let round_offset: i64 = 1 << (scaling - 1);
if let Some(v) = self.static_value {
let slice = (v.wrapping_add(round_offset) >> scaling) as u32 & mask;
statics.push((offset, slice));
} else {
// ensure we emit an unsuffixed literal for this so it works with all
// types of number
let round_offset = Literal::i64_unsuffixed(round_offset);
self.encodes.push((offset, quote_spanned!{ self.span=>
((_dyn_imm.wrapping_add(#round_offset) >> #scaling) as u32 & #mask)
}));
}
},
Some(Command::Next) => break,
Some(_)
| None => panic!("Bad encoding data, integer field sequence is not terminated"),
}
index += 1;
}
}
pub fn emit_dynamic(mut self, is_signed: bool, is_64bit: bool, check: TokenStream, dynamics: &mut Vec<(u8, TokenStream)>) {
// assemble encoding chunks
let mut exprs = [None, None, None, None, None, None, None, None];
let dynamic_value = self.dynamic_value;
let span = self.span;
for (offset, expr) in self.encodes.drain(..) {
let index = usize::from(offset >> 5);
let offset = offset & 0x1F;
exprs[index] = match exprs[index].take() {
Some(prev_expr) => {
let parenthesized = delimited(prev_expr);
Some(if offset == 0 {
let expr = delimited(expr);
quote!{ #parenthesized | #expr }
} else {
quote!{ #parenthesized | (#expr << #offset) }
})
},
None => {
Some(if offset == 0 {
quote!{ #expr }
} else {
quote!{ #expr << #offset }
})
}
}
}
let imm_ty = match (is_64bit, is_signed) {
(false, false) => quote_spanned!{ span=> u32 },
(false, true) => quote_spanned!{ span=> i32 },
(true, false) => quote_spanned!{ span=> u64 },
(true, true) => quote_spanned!{ span=> i64 }
};
let mut first = true;
for (i, expr) in exprs.into_iter().enumerate() {
let encodes = if let Some(encodes) = expr { encodes } else {
continue
};
let offset = (i * 32) as u8;
if first {
first = false;
let error_expr = match (is_64bit, is_signed) {
(false, false) => quote_spanned!{ span=>
::dynasmrt::riscv::immediate_out_of_range_unsigned_32
},
(false, true) => quote_spanned!{ span=>
::dynasmrt::riscv::immediate_out_of_range_signed_32
},
(true, false) => quote_spanned!{ span=>
::dynasmrt::riscv::immediate_out_of_range_unsigned_64
},
(true, true) => quote_spanned!{ span=>
::dynasmrt::riscv::immediate_out_of_range_signed_64
}
};
dynamics.push((offset, quote_spanned!{ span=>
{
let _dyn_imm: #imm_ty = #dynamic_value;
if #check {
#error_expr(_dyn_imm);
}
#encodes
}
}));
} else {
dynamics.push((offset, quote_spanned!{ span=>
{
let _dyn_imm: #imm_ty = #dynamic_value;
#encodes
}
}));
}
}
}
}
/// Checks the following things
/// value >= min
/// (value - min) <= range
/// ((value - min) & bitmask(scale)) == 0
/// returning (value - min) on success.
fn static_range_check(value: i64, min: i32, range: u32, scale: u8, span: Span) -> Result<u32, Option<String>> {
if value < i64::from(min) {
emit_error!(span, "Immediate too low");
return Err(None);
}
let biased = value - i64::from(min);
if biased > i64::from(range) {
emit_error!(span, "Immediate too high");
return Err(None);
}
let biased = biased as u32;
if scale != 0 && (biased & bitmask(scale)) != 0 {
emit_error!(span, "Unrepresentable immediate");
return Err(None);
}
Ok(biased)
}