diff --git a/target/m68k/translate.c b/target/m68k/translate.c
index 6beaf9ed66..e407ba2db3 100644
--- a/target/m68k/translate.c
+++ b/target/m68k/translate.c
@@ -3166,11 +3166,11 @@ DISAS_INSN(subx_mem)
     opsize = insn_opsize(insn);
 
     addr_src = AREG(insn, 0);
-    tcg_gen_subi_i32(addr_src, addr_src, opsize);
+    tcg_gen_subi_i32(addr_src, addr_src, opsize_bytes(opsize));
     src = gen_load(s, opsize, addr_src, 1, IS_USER(s));
 
     addr_dest = AREG(insn, 9);
-    tcg_gen_subi_i32(addr_dest, addr_dest, opsize);
+    tcg_gen_subi_i32(addr_dest, addr_dest, opsize_bytes(opsize));
     dest = gen_load(s, opsize, addr_dest, 1, IS_USER(s));
 
     gen_subx(s, src, dest, opsize);