Merge pull request #7 from xarantolus/master

Evaluate memory region expressions

Author: pftbest

src/eval.rs

@@ -0,0 +1,87 @@
+use crate::expressions::{BinaryOperator, Expression};
+
+pub fn evaluate_expression(expr: Expression) -> Result<u64, String> {
+    Ok(match expr {
+        Expression::Number(n) => n,
+        Expression::BinaryOp {
+            left,
+            operator,
+            right,
+        } => {
+            let left = evaluate_expression(*left)?;
+            let right = evaluate_expression(*right)?;
+            match operator {
+                BinaryOperator::Plus => left.wrapping_add(right),
+                BinaryOperator::Minus => left.wrapping_sub(right),
+                BinaryOperator::Multiply => left.wrapping_mul(right),
+                BinaryOperator::Divide => left.wrapping_div(right),
+                _ => return Err(format!("Binary operator {:?} not supported", operator)),
+            }
+        }
+        _ => return Err(format!("Expression {:?} not supported", expr)),
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use nom::combinator::map_res;
+    use BinaryOperator::*;
+
+    #[test]
+    fn test_evaluate_expression() {
+        assert_eq!(evaluate_expression(Expression::Number(42)), Ok(42));
+
+        assert_eq!(
+            evaluate_expression(Expression::BinaryOp {
+                left: Box::new(Expression::Number(42)),
+                operator: Plus,
+                right: Box::new(Expression::Number(42))
+            }),
+            Ok(84)
+        );
+        assert_eq!(
+            evaluate_expression(Expression::BinaryOp {
+                left: Box::new(Expression::Number(42)),
+                operator: Minus,
+                right: Box::new(Expression::Number(42))
+            }),
+            Ok(0)
+        );
+        assert_eq!(
+            evaluate_expression(Expression::BinaryOp {
+                left: Box::new(Expression::Number(42)),
+                operator: Multiply,
+                right: Box::new(Expression::Number(42))
+            }),
+            Ok(1764)
+        );
+        assert_eq!(
+            evaluate_expression(Expression::BinaryOp {
+                left: Box::new(Expression::Number(42)),
+                operator: Divide,
+                right: Box::new(Expression::Number(42))
+            }),
+            Ok(1)
+        );
+    }
+
+    fn expr_result(input: &str, expected: u64) {
+        assert_done!(
+            map_res(crate::expressions::expression, evaluate_expression)(input),
+            expected
+        );
+    }
+
+    #[test]
+    fn test_parsed_expressions() {
+        expr_result("42 - (20 + 21)", 1);
+        expr_result("42 - (4 * 8)", 10);
+        expr_result("42", 42);
+        expr_result("42 + 42", 84);
+        expr_result("42 - 42", 0);
+        expr_result("42 * 42", 1764);
+        expr_result("42 / 42", 1);
+        expr_result("0x2000000 + (4k * 4)", 0x2000000 + (4 * 1024 * 4));
+    }
+}

src/lib.rs

@@ -29,6 +29,7 @@ mod utils;
 #[macro_use]
 mod whitespace;
 mod commands;
+mod eval;
 mod expressions;
 mod idents;
 mod memory;

src/memory.rs

@@ -2,13 +2,14 @@ use idents::symbol;
 use nom::{
     branch::alt,
     bytes::complete::{tag, take_until},
-    combinator::opt,
+    combinator::{map_res, opt},
     sequence::{delimited, tuple},
     IResult,
 };
-use numbers::number;
 use whitespace::opt_space;
 
+use crate::{eval::evaluate_expression, expressions::expression};
+
 #[derive(Debug, PartialEq)]
 pub struct Region {
     pub name: String,
@@ -37,15 +38,15 @@ pub fn region(input: &str) -> IResult<&str, Region> {
         origin,
         wsc!(tag("=")),
     ))(input)?;
-    let (input, org) = number(input)?;
+    let (input, origin) = map_res(expression, evaluate_expression)(input)?;
     let (input, _) = tuple((wsc!(tag(",")), length, wsc!(tag("="))))(input)?;
-    let (input, len) = number(input)?;
+    let (input, length) = map_res(expression, evaluate_expression)(input)?;
     Ok((
         input,
         Region {
             name: name.into(),
-            origin: org,
-            length: len,
+            origin,
+            length,
         },
     ))
 }
@@ -73,4 +74,52 @@ mod tests {
             }
         );
     }
+
+    #[test]
+    fn test_region_expr() {
+        assert_done!(
+            region("FLASH : ORIGIN = 0x08000000, LENGTH = 8K"),
+            Region {
+                name: "FLASH".into(),
+                origin: 0x08000000,
+                length: 8 * 1024,
+            }
+        );
+
+        assert_done!(
+            region("RAM : ORIGIN = 0x20000000 + 8K, LENGTH = 640K"),
+            Region {
+                name: "RAM".into(),
+                origin: 0x20000000 + 8 * 1024,
+                length: 640 * 1024,
+            }
+        );
+
+        assert_done!(
+            region("RAM : ORIGIN = 0x20000000, LENGTH = 640K - 8K"),
+            Region {
+                name: "RAM".into(),
+                origin: 0x20000000,
+                length: 640 * 1024 - 8 * 1024,
+            }
+        );
+
+        assert_done!(
+            region("RAM : ORIGIN = 0x20000000 + 8K - 4K, LENGTH = 640K - 8K + 4K"),
+            Region {
+                name: "RAM".into(),
+                origin: 0x20000000 + 4 * 1024,
+                length: 640 * 1024 - 4 * 1024,
+            }
+        );
+
+        assert_done!(
+            region("RAM: ORIGIN = 0x20000000 + 8K - 4K, LENGTH = 640K - 8K + 4K"),
+            Region {
+                name: "RAM".into(),
+                origin: 0x20000000 + 4 * 1024,
+                length: 640 * 1024 - 4 * 1024,
+            }
+        );
+    }
 }

src/script.rs

@@ -63,6 +63,13 @@ mod tests {
         assert_done_vec!(parse("      /* hello */              "), 0);
     }
 
+    #[test]
+    fn test_bootloader() {
+        let input = include_str!("../tests/bootloader.ld");
+        let res = parse(&input);
+        assert!(!res.unwrap().1.is_empty());
+    }
+
     #[test]
     fn test_parse() {
         for entry in fs::read_dir("tests").unwrap() {

tests/bootloader.ld

@@ -0,0 +1,6 @@
+MEMORY
+{
+  FLASH : ORIGIN = 0x08000000, LENGTH = 8K
+
+  RAM : ORIGIN = 0x20000000 + 256K, LENGTH = 640K - 256K
+}