diff --git a/util/disassembler.c b/util/disassembler.c
index 3970211..80f1743 100644
--- a/util/disassembler.c
+++ b/util/disassembler.c
@@ -637,8 +637,8 @@ static VBU_DasmLine* dasmDisassemble(VB *sim, uint32_t address,
     }
 
     /* Begin decoding from at least 10 lines before first/reference */
-    addr = (address & 0xFFFFFFFE) +
-        (int32_t) ((line < 0 ? -line : 0) - 10) * 4;
+    addr = (address & 0xFFFFFFFE) -
+        (int32_t) (line <= 0 ? 10 : line + 10) * 4;
 
     /* Locate the address of the line containing the reference address */
     pc = vbGetProgramCounter(sim);