feat: add parsing for push

src/bin/ponderosa-asm.rs

@@ -6,11 +6,24 @@ use std::collections::{HashMap, BTreeMap, VecDeque};
 
 use ponderosa::state::{Land, Rule};
 
+macro_rules! assert_argument_count {
+    ($tokens:expr, $count:expr) => {
+        if $tokens.len() < $count {
+            return Err("Too few arguments".to_owned());
+        }
+
+        if $tokens.len() > $count {
+            return Err("Too many arguments".to_owned());
+        }
+    };
+}
+
 fn parse_number(string: &str) -> u16 {
     string.parse::<u16>().unwrap()
 }
 
-fn stack_bit(c: char) -> Result<u16, String> {
+fn stack_bit(token: &String) -> Result<u16, String> {
+    let c = token.as_bytes()[0] as char;
     match c {
         'r' => Ok(0),
         't' => Ok(1),
@@ -18,27 +31,42 @@ fn stack_bit(c: char) -> Result<u16, String> {
     }
 }
 
-fn parse_binary_math_format<'a>(tokens: &Vec<String>, opcode: u16, signed: bool) -> Result<u16, String> {
-    if tokens.len() < 4 { Err("Too few arguments".to_owned()) }
-    else if tokens.len() > 4 { Err("Too many arguments".to_owned()) }
-    else {
-        let left_parse = stack_bit(tokens[1].as_bytes()[0] as char);
-        let right_parse = stack_bit(tokens[2].as_bytes()[0] as char);
-        let dest_parse = stack_bit(tokens[3].as_bytes()[0] as char);
+fn parse_unary_math_format<'a>(tokens: &Vec<String>, opcode: u16, signed: bool) -> Result<u16, String> {
+    assert_argument_count!(tokens, 4);
 
-        match (left_parse, right_parse, dest_parse) {
-            (Ok(left), Ok(right), Ok(dest)) => Ok(
-                opcode << 11 &
-                left << 10 &
-                right << 9 &
-                dest << 8 &
-                (signed as u16) << 7
-            ),
-            (Err(e), _, _) => Err(e),
-            (_, Err(e), _) => Err(e),
-            (_, _, Err(e)) => Err(e),
-        }
+    let src = stack_bit(&tokens[1])?;
+    let dest = stack_bit(&tokens[2])?;
+
+    Ok(opcode<<11 & src<<9 & dest<<8 & (signed as u16)<<7)
+}
+
+fn parse_binary_math_format<'a>(tokens: &Vec<String>, opcode: u16, signed: bool) -> Result<u16, String> {
+    assert_argument_count!(tokens, 4);
+
+    let left = stack_bit(&tokens[1])?;
+    let right = stack_bit(&tokens[2])?;
+    let dest = stack_bit(&tokens[3])?;
+
+    Ok(opcode<<11 & left<<10 & right<<9 & dest<<8 & (signed as u16)<<7)
+}
+
+fn parse_push(tokens: &Vec<String>, opcode: u16, signed: bool) -> Result<u16, String> {
+    assert_argument_count!(tokens, 3);
+
+    let dest = stack_bit(&tokens[1])?;
+    let signed_immediate = tokens[2].parse::<i16>()
+        .map_err(|_| format!("Cannot parse number: {t}", t=tokens[2]))?;
+
+    let unsigned_immediate = tokens[2].parse::<u16>()
+        .map_err(|_| format!("Cannot parse number: {t}", t=tokens[2]))?;
+
+    let immediate = if signed { signed_immediate as u16 } else { unsigned_immediate };
+
+    if immediate > 511 {
+        return Err("Cannot push number larger than 511 due to bit width limitations".to_owned());
     }
+
+    Ok(opcode<<11 & dest<<10 & (signed as u16) << 9 & immediate)
 }
 
 fn main() -> io::Result<()> {