diff --git a/hdl/core.v b/hdl/core.v
index 5f44490..510bab4 100644
--- a/hdl/core.v
+++ b/hdl/core.v
@@ -218,7 +218,7 @@ always @(*) begin
             casex ({s_id_funct3, s_id_funct7})
                 10'b000xxxxxxx: s_id_aluop = ALUOP_ADD;     // ADDI
                 10'b010xxxxxxx: s_id_aluop = ALUOP_SLT;     // SLTI
-                10'b011xxxxxxx: s_id_aluop = ALUOP_SLTU;    // SLTUI
+                10'b011xxxxxxx: s_id_aluop = ALUOP_SLTU;    // SLTIU
                 10'b100xxxxxxx: s_id_aluop = ALUOP_XOR;     // XORI
                 10'b110xxxxxxx: s_id_aluop = ALUOP_OR;      // ORI
                 10'b111xxxxxxx: s_id_aluop = ALUOP_AND;     // ANDI
diff --git a/test/test.S b/test/test.S
index 4331036..9526359 100644
--- a/test/test.S
+++ b/test/test.S
@@ -8,12 +8,6 @@ _start:
     # JAL
     # JALR
 
-    # SLTI
-    # SLTUI
-
-    # SLT
-    # SLTU
-
     # lui
     lui     x1, 0xfedcb         # x1  = 0xfedcb000
     nop
@@ -154,6 +148,57 @@ _start:
     nop
     nop
 
+    # slti
+    addi    x3, x0, 1           # x3  = 0x00000001
+    addi    x4, x0, 0x010       # x4  = 0x00000010
+    addi    x5, x0, 0x100       # x5  = 0x00000100
+    nop
+    sub     x6, x0, x3          # x6  = 0xffffffff
+    sub     x7, x0, x4          # x7  = 0xfffffff0
+    sub     x8, x0, x5          # x7  = 0xffffff00
+    nop
+    slti    x9, x3, 0           # x9  = 0x00000000
+    slti    x10, x3, 1          # x10 = 0x00000000
+    slti    x11, x3, 2          # x11 = 0x00000001
+    slti    x12, x3, -1         # x12 = 0x00000000
+    slti    x13, x7, 0          # x13 = 0x00000001
+    slti    x14, x7, -17        # x14 = 0x00000000
+    nop
+    nop
+    nop
+
+    # sltiu
+    sltiu   x15, x3, 0          # x15 = 0x00000000
+    sltiu   x16, x3, 1          # x16 = 0x00000000
+    sltiu   x17, x3, 2          # x17 = 0x00000001
+    sltiu   x18, x3, -1         # x18 = 0x00000001      # -1=0xffffffff
+    sltiu   x19, x7, 0          # x19 = 0x00000000
+    sltiu   x20, x7, -15        # x20 = 0x00000001      # -15=0xfffffff1
+    nop
+    nop
+    nop
+
+    # slt
+    slt     x21, x0, x3         # x21 = 0x00000001
+    slt     x22, x3, x0         # x22 = 0x00000000
+    slt     x23, x3, x3         # x23 = 0x00000000
+    slt     x24, x3, x6         # x24 = 0x00000000
+    slt     x25, x6, x3         # x25 = 0x00000001
+    nop
+    nop
+    nop
+
+    # sltu
+    sltu    x26, x0, x3         # x26 = 0x00000001
+    sltu    x27, x3, x0         # x27 = 0x00000000
+    sltu    x28, x3, x3         # x28 = 0x00000000
+    sltu    x29, x3, x6         # x29 = 0x00000001
+    sltu    x30, x6, x3         # x30 = 0x00000000
+    nop
+    nop
+    nop
+
+
     # counter and infinite loop
     nop
     nop