diff --git a/model/riscv_step.sail b/model/riscv_step.sail
index 8e94c16b7..40c0c80c3 100644
--- a/model/riscv_step.sail
+++ b/model/riscv_step.sail
@@ -98,6 +98,7 @@ function step(step_no : int) -> bool = {
           },
           /* non-error cases: */
           F_RVC(h) => {
+            instbits = EXTZ(h);
             let ast = decodeCompressed(h);
             if   get_config_print_instr()
             then {
@@ -113,6 +114,7 @@ function step(step_no : int) -> bool = {
              }
           },
           F_Base(w) => {
+            instbits = EXTZ(w);
             let ast = decode(w);
             if   get_config_print_instr()
             then {