diff --git a/src/codegen_new/codegen_backend_arm64_ops.c b/src/codegen_new/codegen_backend_arm64_ops.c
index 5667d2c93..594a5d524 100644
--- a/src/codegen_new/codegen_backend_arm64_ops.c
+++ b/src/codegen_new/codegen_backend_arm64_ops.c
@@ -684,7 +684,7 @@ host_arm64_CMPX_IMM(codeblock_t *block, int src_n_reg, uint64_t imm_data)
     } else if (!(imm_data & 0xfffffffffffff000ull)) {
         codegen_addlong(block, OPCODE_CMPX_IMM | Rd(REG_XZR) | Rn(src_n_reg) | IMM12(imm_data & 0xfff) | DATPROC_IMM_SHIFT(0));
     } else
-        fatal("CMPX_IMM %08x\n", imm_data);
+        fatal("CMPX_IMM %08llx\n", imm_data);
 }
 
 void