Fix PPC branch display; update README.md

objdiff-core/src/diff/display.rs

@@ -74,7 +74,11 @@ pub fn display_diff<E>(
                 display_reloc_name(ins.reloc.as_ref().unwrap(), &mut cb)?;
             }
             ObjInsArg::BranchDest(dest) => {
-                cb(DiffText::BranchDest(*dest))?;
+                if let Some(dest) = dest.checked_sub(base_addr) {
+                    cb(DiffText::BranchDest(dest))?;
+                } else {
+                    cb(DiffText::Basic("<unknown>"))?;
+                }
             }
         }
     }

objdiff-core/src/diff/mod.rs

@@ -23,10 +23,14 @@ pub enum X86Formatter {
     Masm,
 }
 
+#[inline]
+const fn default_true() -> bool { true }
+
 #[derive(Debug, Clone, Default, Eq, PartialEq, serde::Deserialize, serde::Serialize)]
 #[serde(default)]
 pub struct DiffObjConfig {
     pub relax_reloc_diffs: bool,
+    #[serde(default = "default_true")]
     pub space_between_args: bool,
     pub x86_formatter: X86Formatter,
 }