diff --git a/nemu/src/isa/riscv32/inst.c b/nemu/src/isa/riscv32/inst.c
index b79bb00..c26c797 100644
--- a/nemu/src/isa/riscv32/inst.c
+++ b/nemu/src/isa/riscv32/inst.c
@@ -24,7 +24,7 @@
 #define Mw vaddr_write
 
 enum {
-  TYPE_R, TYPE_I, TYPE_U, TYPE_S, TYPE_B, TYPE_J,
+  TYPE_R, TYPE_I, TYPE_I_SHIFT, TYPE_U, TYPE_S, TYPE_B, TYPE_J,
   TYPE_N, // none
 };
 
@@ -71,6 +71,7 @@ static int decode_exec(Decode *s) {
   INSTPAT_START();
   INSTPAT("??????? ????? ????? ??? ????? 01101 11", lui    , U, R(rd) = imm);
   INSTPAT("??????? ????? ????? ??? ????? 00101 11", auipc  , U, R(rd) = s->pc + imm);
+
   INSTPAT("??????? ????? ????? ??? ????? 11011 11", jal    , J, do {s->dnpc = s->pc + imm; R(rd) = s->pc + 4; } while(0));
   INSTPAT("??????? ????? ????? ??? ????? 11001 11", jalr   , I, do {s->dnpc = src1 + imm; R(rd) = s->pc + 4; } while(0));
   INSTPAT("??????? ????? ????? 000 ????? 11000 11", beq    , B, do_branch(s, src1 == src2, imm));
@@ -79,6 +80,7 @@ static int decode_exec(Decode *s) {
   INSTPAT("??????? ????? ????? 101 ????? 11000 11", bge    , B, do_branch(s, (sword_t)src1 >= (sword_t)src2, imm));
   INSTPAT("??????? ????? ????? 110 ????? 11000 11", bltu   , B, do_branch(s, src1 < src2, imm));
   INSTPAT("??????? ????? ????? 111 ????? 11000 11", bgeu   , B, do_branch(s, src1 >= src2, imm));
+
   INSTPAT("??????? ????? ????? 000 ????? 00000 11", lb     , I, R(rd) = SEXT(Mr(src1 + imm, 1), 8));
   INSTPAT("??????? ????? ????? 001 ????? 00000 11", lh     , I, R(rd) = SEXT(Mr(src1 + imm, 2), 16));
   INSTPAT("??????? ????? ????? 010 ????? 00000 11", lw     , I, R(rd) = SEXT(Mr(src1 + imm, 4), 32));
@@ -87,8 +89,28 @@ static int decode_exec(Decode *s) {
   INSTPAT("??????? ????? ????? 000 ????? 01000 11", sb     , S, Mw(src1 + imm, 1, src2));
   INSTPAT("??????? ????? ????? 001 ????? 01000 11", sh     , S, Mw(src1 + imm, 2, src2));
   INSTPAT("??????? ????? ????? 010 ????? 01000 11", sw     , S, Mw(src1 + imm, 4, src2));
+
   INSTPAT("??????? ????? ????? 000 ????? 00100 11", addi   , I, R(rd) = src1 + imm);
+  INSTPAT("??????? ????? ????? 010 ????? 00100 11", slti   , I, R(rd) = (sword_t)src1 < (sword_t)imm ? 1 : 0);
+  INSTPAT("??????? ????? ????? 011 ????? 00100 11", sltiu  , I, R(rd) = src1 < imm ? 1 : 0);
+  INSTPAT("??????? ????? ????? 100 ????? 00100 11", xori   , I, R(rd) = src1 ^ imm);
+  INSTPAT("??????? ????? ????? 110 ????? 00100 11", ori    , I, R(rd) = src1 | imm);
+  INSTPAT("??????? ????? ????? 111 ????? 00100 11", andi   , I, R(rd) = src1 & imm);
+  INSTPAT("0000000 ????? ????? 001 ????? 00100 11", slli   , I, R(rd) = src1 << imm);
+  INSTPAT("0000000 ????? ????? 101 ????? 00100 11", srli   , I, R(rd) = src1 >> imm);
+  INSTPAT("0100000 ????? ????? 101 ????? 00100 11", srai   , I, R(rd) = (sword_t)src1 >> (imm & 0x01F));
+  
+
   INSTPAT("0000000 ????? ????? 000 ????? 01100 11", add    , R, R(rd) = src1 + src2);
+  INSTPAT("0100000 ????? ????? 000 ????? 01100 11", sub    , R, R(rd) = src1 - src2);
+  INSTPAT("0000000 ????? ????? 001 ????? 01100 11", sll    , R, R(rd) = src1 << src2);
+  INSTPAT("0000000 ????? ????? 010 ????? 01100 11", slt    , R, R(rd) = (sword_t)src1 < (sword_t)src2 ? 1 : 0);
+  INSTPAT("0000000 ????? ????? 011 ????? 01100 11", sltu   , R, R(rd) = src1 < src2 ? 1 : 0);
+  INSTPAT("0000000 ????? ????? 100 ????? 01100 11", xor    , R, R(rd) = src1 ^ src2);
+  INSTPAT("0000000 ????? ????? 101 ????? 01100 11", srl    , R, R(rd) = src1 >> src2);
+  INSTPAT("0100000 ????? ????? 101 ????? 01100 11", sra    , R, R(rd) = (sword_t)src1 >> (src2 & 0x01F));
+  INSTPAT("0000000 ????? ????? 110 ????? 01100 11", or     , R, R(rd) = src1 | src2);
+  INSTPAT("0000000 ????? ????? 111 ????? 01100 11", and    , R, R(rd) = src1 & src2);
 
   INSTPAT("0000000 00001 00000 000 00000 11100 11", ebreak , N, NEMUTRAP(s->pc, R(10))); // R(10) is $a0
   INSTPAT("??????? ????? ????? ??? ????? ????? ??", inv    , N, INV(s->pc));