diff --git a/assembly/src/assembler/instruction/mem_ops.rs b/assembly/src/assembler/instruction/mem_ops.rs
index c3eaa3633..90c610c89 100644
--- a/assembly/src/assembler/instruction/mem_ops.rs
+++ b/assembly/src/assembler/instruction/mem_ops.rs
@@ -1,9 +1,8 @@
 use alloc::string::ToString;
-
 use vm_core::{Felt, Operation::*};
 
-use super::{push_felt, push_u32_value, validate_param, BasicBlockBuilder};
-use crate::{assembler::ProcedureContext, diagnostics::Report, AssemblyError};
+use super::{push_felt, push_u32_value, BasicBlockBuilder};
+use crate::{assembler::ProcedureContext, diagnostics::Report, Spanned, AssemblyError};
 
 // INSTRUCTION PARSERS
 // ================================================================================================
@@ -32,8 +31,7 @@ pub fn mem_read(
     // if the address was provided as an immediate value, put it onto the stack
     if let Some(addr) = addr {
         if is_local {
-            let num_locals = proc_ctx.num_locals();
-            local_to_absolute_addr(block_builder, addr as u16, num_locals, is_single)?;
+            local_to_absolute_addr(block_builder, addr as u16, proc_ctx)?;
         } else {
             push_u32_value(block_builder, addr);
         }
@@ -81,7 +79,7 @@ pub fn mem_write_imm(
     is_single: bool,
 ) -> Result<(), AssemblyError> {
     if is_local {
-        local_to_absolute_addr(block_builder, addr as u16, proc_ctx.num_locals(), is_single)?;
+        local_to_absolute_addr(block_builder, addr as u16, proc_ctx)?;
     } else {
         push_u32_value(block_builder, addr);
     }
@@ -111,10 +109,10 @@ pub fn mem_write_imm(
 /// Returns an error if index is greater than the number of procedure locals.
 pub fn local_to_absolute_addr(
     block_builder: &mut BasicBlockBuilder,
-    index_of_local: u16,
-    num_proc_locals: u16,
-    is_single: bool,
+    index: u16,
+    proc_ctx: &ProcedureContext,
 ) -> Result<(), AssemblyError> {
+    let num_proc_locals = proc_ctx.num_locals();
     if num_proc_locals == 0 {
         return Err(AssemblyError::Other(
             Report::msg(
@@ -125,21 +123,17 @@ pub fn local_to_absolute_addr(
         ));
     }
 
-    // If a single local value is being accessed, then the index can take the full range
-    // [0, num_proc_locals - 1]. Otherwise, the index can take the range [0, num_proc_locals - 4]
-    // to account for the fact that a full word is being accessed.
-    let max = if is_single {
-        num_proc_locals - 1
-    } else {
-        num_proc_locals - 4
-    };
-    validate_param(index_of_local, 0..=max)?;
+    let max_index = num_proc_locals - 1;
+    if index > max_index {
+        let span = proc_ctx.span();
+        return Err(AssemblyError::InvalidLocalWordIndex {
+            span,
+            source_file: proc_ctx.source_manager().get(span.source_id()).ok(),
+            local_addr: index,
+        });
+    }
 
-    // Local values are placed under the frame pointer, so we need to calculate the offset of the
-    // local value from the frame pointer.
-    // The offset is in the range [1, num_proc_locals], which is then subtracted from `fmp`.
-    let fmp_offset_of_local = num_proc_locals - index_of_local;
-    push_felt(block_builder, -Felt::from(fmp_offset_of_local));
+    push_felt(block_builder, -Felt::from(max_index - index));
     block_builder.push_op(FmpAdd);
 
     Ok(())
diff --git a/assembly/src/errors.rs b/assembly/src/errors.rs
index 06ff9ab3b..aa36bd334 100644
--- a/assembly/src/errors.rs
+++ b/assembly/src/errors.rs
@@ -88,6 +88,17 @@ pub enum AssemblyError {
         #[source_code]
         source_file: Option<Arc<SourceFile>>,
     },
+    #[error("invalid local memory index: {index} is out of bounds")]
+    #[diagnostic(help("procedure has {num_locals} locals available, so the valid range for the index is 0..{max_index}"))]
+    InvalidLocalMemoryIndex {
+        #[label("invalid index used here")]
+        span: SourceSpan,
+        #[source_code]
+        source_file: Option<Arc<SourceFile>>,
+        index: u16,
+        num_locals: u16,
+        max_index: u16,
+    },
     #[error(transparent)]
     #[diagnostic(transparent)]
     Other(RelatedError),