Rewrite entire assembler

The language is now more general, the code is better structured, error
reporting is more detailed, and many new language features have
been implemented:
- conditional blocks
- first-class strings
- more expression operators
- binary literals
- negative values
- invocations in constant expressions

1 files changed, 46 insertions, 0 deletions

diff --git a/src/types/word_template.rs b/src/types/word_template.rs
new file mode 100644
index 0000000..33d5933
--- /dev/null
+++ b/src/types/word_template.rs
@@ -0,0 +1,46 @@
+use crate::*;
+
+
+pub struct WordTemplate {
+    pub value: usize,
+    /// Width of the word in bits.
+    pub width: u32,
+    pub fields: Vec<Tracked<BitField>>,
+}
+
+pub struct BitField {
+    pub name: char,
+    /// Width of the field in bits.
+    pub width: u32,
+    /// Number of bits to the right of the field in the word.
+    pub shift: u32,
+}
+
+
+impl std::fmt::Display for WordTemplate {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
+        if self.value == 0 {
+            write!(f, "0")?;
+        } else {
+            let bitcount = (self.value.ilog2() + 1) as usize;
+            'bit: for i in (0..bitcount).rev() {
+                let is_first_bit = i+1 == bitcount;
+                if !is_first_bit && (i+1) % 4 == 0 {
+                    write!(f, "_")?;
+                }
+                for field in &self.fields {
+                    let i = i as u32;
+                    if i <= field.width + field.shift - 1 && i >= field.shift {
+                        write!(f, "{}", field.name)?;
+                        continue 'bit;
+                    }
+                }
+                match (self.value >> i) & 1 {
+                    0 => write!(f, "0")?,
+                    _ => write!(f, "1")?,
+                }
+            }
+        }
+        return Ok(());
+    }
+}