juicebox_asm/
imm.rs

1// SPDX-License-Identifier: MIT
2//
3// Copyright (c) 2023, Johannes Stoelp <dev@memzero.de>
4
5//! Definition of different immediate types which are used as input operands for various
6//! instructions.
7
8/// Trait to interact with immediate operands.
9pub(crate) trait Imm {
10    /// Get immediate operand as slice of bytes.
11    fn bytes(&self) -> &[u8];
12}
13
14macro_rules! impl_imm {
15    (#[$doc:meta] $name:ident, $size:expr, from: { $( $from:ty ),* $(,)? }) => {
16        #[$doc]
17        pub struct $name([u8; $size]);
18
19        impl Imm for $name {
20            /// Get immediate operand as slice of bytes.
21            fn bytes(&self) -> &[u8] {
22                &self.0
23            }
24        }
25
26        impl $name {
27            pub fn splat_u8(val: u8) -> $name {
28                $name([val; $size])
29            }
30        }
31
32        $(
33        impl From<$from> for $name {
34            fn from(imm: $from) -> Self {
35                let mut buf = [0u8; $size];
36                let imm = imm.to_ne_bytes();
37                buf[0..imm.len()].copy_from_slice(&imm);
38                $name(buf)
39            }
40        }
41        )*
42    }
43}
44
45impl_imm!(
46    /// Type representing an 8 bit immediate.
47    Imm8, 1, from: { u8, i8 }
48);
49impl_imm!(
50    /// Type representing a 16 bit immediate.
51    Imm16, 2, from: { u16, i16, u8, i8 }
52);
53impl_imm!(
54    /// Type representing a 32 bit immediate.
55    Imm32, 4, from: { u32, i32, u16, i16, u8, i8 }
56);
57impl_imm!(
58    /// Type representing a 64 bit immediate.
59    Imm64, 8, from: { u64, i64, u32, i32, u16, i16, u8, i8, usize, isize }
60);
61
62#[cfg(test)]
63mod test {
64    use super::*;
65    use std::mem::size_of;
66
67    #[test]
68    fn test_usize_isize() {
69        // Imm64 should not implementd from usize/isize if this fails.
70        assert_eq!(size_of::<usize>(), size_of::<Imm64>());
71        assert_eq!(size_of::<isize>(), size_of::<Imm64>());
72    }
73}
juicebox_asm/imm.rs

juicebox_asm/
imm.rs
