diff --git a/nemu/src/isa/riscv32/inst.c b/nemu/src/isa/riscv32/inst.c
index 08e0415..d06de29 100644
--- a/nemu/src/isa/riscv32/inst.c
+++ b/nemu/src/isa/riscv32/inst.c
@@ -66,6 +66,7 @@ static int decode_exec(Decode *s) {
   INSTPAT("??????? ????? ????? ??? ????? 11001 11", jalr   , I, do {s->dnpc = s->pc + src1; R(rd) = s->pc + 4; } while(0));
   INSTPAT("??????? ????? ????? 100 ????? 00000 11", lbu    , I, R(rd) = Mr(src1 + imm, 1));
   INSTPAT("??????? ????? ????? 000 ????? 01000 11", sb     , S, Mw(src1 + imm, 1, src2));
+  INSTPAT("??????? ????? ????? 010 ????? 01000 11", sw     , S, Mw(src1 + imm, 4, src2));
   INSTPAT("??????? ????? ????? 000 ????? 00100 11", addi   , I, R(rd) = src1 + (sword_t)imm);
   INSTPAT("0000000 ????? ????? 000 ????? 01100 11", add    , R, R(rd) = src1 + src2);