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Use a struct interface for creating and reading encoding bits on x86. #1156 (#1212)

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This commit is contained in:
Sean Stangl
2019-11-13 18:01:13 -07:00
committed by GitHub
parent b578fd5396
commit f8ae622003
7 changed files with 273 additions and 45 deletions
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32
cranelift/codegen/meta/src/isa/x86/recipes.rs
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@@ -1,5 +1,8 @@
//! Encoding recipes for x86/x86_64.
use std::rc::Rc;
use cranelift_codegen_shared::isa::x86::EncodingBits;
use crate::cdsl::ast::Literal;
use crate::cdsl::formats::InstructionFormat;
use crate::cdsl::instructions::InstructionPredicate;
@@ -96,33 +99,8 @@ impl<'builder> RecipeGroup<'builder> {
/// Given a sequence of opcode bytes, compute the recipe name prefix and encoding bits.
fn decode_opcodes(op_bytes: &[u8], rrr: u16, w: u16) -> (&'static str, u16) {
assert!(!op_bytes.is_empty(), "at least one opcode byte");
let prefix_bytes = &op_bytes[..op_bytes.len() - 1];
let (name, mmpp) = match prefix_bytes {
[] => ("Op1", 0b000),
[0x66] => ("Mp1", 0b0001),
[0xf3] => ("Mp1", 0b0010),
[0xf2] => ("Mp1", 0b0011),
[0x0f] => ("Op2", 0b0100),
[0x66, 0x0f] => ("Mp2", 0b0101),
[0xf3, 0x0f] => ("Mp2", 0b0110),
[0xf2, 0x0f] => ("Mp2", 0b0111),
[0x0f, 0x38] => ("Op3", 0b1000),
[0x66, 0x0f, 0x38] => ("Mp3", 0b1001),
[0xf3, 0x0f, 0x38] => ("Mp3", 0b1010),
[0xf2, 0x0f, 0x38] => ("Mp3", 0b1011),
[0x0f, 0x3a] => ("Op3", 0b1100),
[0x66, 0x0f, 0x3a] => ("Mp3", 0b1101),
[0xf3, 0x0f, 0x3a] => ("Mp3", 0b1110),
[0xf2, 0x0f, 0x3a] => ("Mp3", 0b1111),
_ => {
panic!("unexpected opcode sequence: {:?}", op_bytes);
}
};
let opcode_byte = u16::from(op_bytes[op_bytes.len() - 1]);
(name, opcode_byte | (mmpp << 8) | (rrr << 12) | w << 15)
let enc = EncodingBits::new(op_bytes, rrr, w);
(enc.prefix.recipe_name_prefix(), enc.bits())
}
/// Given a snippet of Rust code (or None), replace the `PUT_OP` macro with the