diff --git a/src/instructions/rvi.rs b/src/instructions/rvi.rs
index e85934d..1fe1c7a 100644
--- a/src/instructions/rvi.rs
+++ b/src/instructions/rvi.rs
@@ -41,7 +41,7 @@ pub fn sd(core: &mut Core, instr: Instruction) -> InstructionResult {
     }
 
     let page = (addr / 4096) as PageNum;
-    let offset = (addr & ((4096 / std::mem::size_of::<DWord>() as Addr) - 1)) as u16;
+    let offset = (addr / 8 & ((4096 / 8 as Addr) - 1)) as u16;
     let value = core.reg_read(instr.rs2());
 
     match core.mem.write_dword(page, offset, value) {