diff --git a/src/cpu.rs b/src/cpu.rs
index edfbba8..677fa83 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -208,9 +208,24 @@ pub fn exec_lwu(cpu: &mut CPU, instr: u32) {
         .bus
         .load(cpu.xregs.regs[rs1(instr) as usize].wrapping_add(imm), 32);
 }
-pub fn exec_sb(cpu: &mut CPU, instr: u32) {}
-pub fn exec_sh(cpu: &mut CPU, instr: u32) {}
-pub fn exec_sw(cpu: &mut CPU, instr: u32) {}
+pub fn exec_sb(cpu: &mut CPU, instr: u32) {
+    let imm = imm_s(instr) as i32;
+    let addr = (cpu.xregs.regs[rs1(instr) as usize] as i32).wrapping_add(imm) as u32;
+    let val = cpu.xregs.regs[rs2(instr) as usize] & std::u8::MAX as u32;
+    cpu.bus.store(addr, 8, val);
+}
+pub fn exec_sh(cpu: &mut CPU, instr: u32) {
+    let imm = imm_s(instr) as i32;
+    let addr = (cpu.xregs.regs[rs1(instr) as usize] as i32).wrapping_add(imm) as u32;
+    let val = cpu.xregs.regs[rs2(instr) as usize] & std::u16::MAX as u32;
+    cpu.bus.store(addr, 16, val);
+}
+pub fn exec_sw(cpu: &mut CPU, instr: u32) {
+    let imm = imm_s(instr) as i32;
+    let addr = (cpu.xregs.regs[rs1(instr) as usize] as i32).wrapping_add(imm) as u32;
+    let val = cpu.xregs.regs[rs2(instr) as usize] & std::u32::MAX as u32;
+    cpu.bus.store(addr, 32, val);
+}
 pub fn exec_addi(cpu: &mut CPU, instr: u32) {
     let imm = imm_i(instr);
     cpu.xregs.regs[rd(instr) as usize] = cpu.xregs.regs[rs1(instr) as usize] + imm as u32;
diff --git a/src/memory.rs b/src/memory.rs
index 48a78de..20ddd49 100644
--- a/src/memory.rs
+++ b/src/memory.rs
@@ -94,6 +94,7 @@ impl MEMORY {
         self.mem[index] = (value & (std::u8::MAX as u32)) as u8;
         self.mem[index + 1] = ((value >> 8) & (std::u8::MAX as u32)) as u8;
         self.mem[index + 2] = ((value >> 16) & (std::u8::MAX as u32)) as u8;
+        self.mem[index + 3] = ((value >> 24) & (std::u8::MAX as u32)) as u8;
     }
     // fn store64(&mut self, addr: u32, value: u32) {
     //     let index = (addr - MEM_BASE) as usize;
diff --git a/tests/cpu_test.rs b/tests/cpu_test.rs
index 977f76c..55a012a 100644
--- a/tests/cpu_test.rs
+++ b/tests/cpu_test.rs
@@ -233,7 +233,7 @@ mod tests {
     fn test_exec_lw() {
         let mut cpu_test = cpu::CPU::new();
         let offset = 3;
-        let val = 11;
+        let val = (-2 as i32) as u32;
         let rd = 5 + MEM_BASE;
         cpu_test.bus.store(rd + offset, 32, val);
         // set x1=5+MEM_BASE
@@ -247,7 +247,7 @@ mod tests {
     fn test_exec_lbu() {
         let mut cpu_test = cpu::CPU::new();
         let offset = 3;
-        let val = 11;
+        let val = (-2 as i32) as u32;
         let rd = 5 + MEM_BASE;
         cpu_test.bus.store(rd + offset, 8, val);
         // set x1=5+MEM_BASE
@@ -255,18 +255,78 @@ mod tests {
         // lbu x31, x1, 3
         let instr: u32 = helper::set_load_type_instruction(offset as i16, 1, LBU as u8, 31);
         cpu::exec_lbu(&mut cpu_test, instr);
-        assert_eq!(cpu_test.xregs.regs[31], val);
+        assert_eq!(cpu_test.xregs.regs[31], val & std::u8::MAX as u32);
     }
     #[test]
-    fn test_exec_lhu() {}
+    fn test_exec_lhu() {
+        let mut cpu_test = cpu::CPU::new();
+        let offset = 3;
+        let val = (-2 as i32) as u32;
+        let rd = 5 + MEM_BASE;
+        cpu_test.bus.store(rd + offset, 16, val);
+        // set x1=5+MEM_BASE
+        helper::set_register_val(&mut cpu_test, 1, rd as i32);
+        // lhu x31, x1, 3
+        let instr: u32 = helper::set_load_type_instruction(offset as i16, 1, LHU as u8, 31);
+        cpu::exec_lhu(&mut cpu_test, instr);
+        assert_eq!(cpu_test.xregs.regs[31], val & std::u16::MAX as u32);
+    }
     #[test]
-    fn test_exec_lwu() {}
+    fn test_exec_lwu() {
+        let mut cpu_test = cpu::CPU::new();
+        let offset = 3;
+        let val = (-2 as i32) as u32;
+        let rd = 5 + MEM_BASE;
+        cpu_test.bus.store(rd + offset, 32, val);
+        // set x1=5+MEM_BASE
+        helper::set_register_val(&mut cpu_test, 1, rd as i32);
+        // lwu x31, x1, 3
+        let instr: u32 = helper::set_load_type_instruction(offset as i16, 1, LWU as u8, 31);
+        cpu::exec_lwu(&mut cpu_test, instr);
+        assert_eq!(cpu_test.xregs.regs[31], val & std::u32::MAX);
+    }
     #[test]
-    fn test_exec_sb() {}
+    fn test_exec_sb() {
+        let mut cpu_test = cpu::CPU::new();
+        let offset = 3;
+        let val = (-2 as i32) as u32;
+        let rd = 5 + MEM_BASE;
+        helper::set_register_val(&mut cpu_test, 29, rd as i32);
+        helper::set_register_val(&mut cpu_test, 30, val as i32);
+        // sb x30, x29, 3
+        let instr: u32 = helper::set_s_type_instruction(offset as i16, 30, 29, SB as u8);
+        cpu::exec_sb(&mut cpu_test, instr);
+        assert_eq!(cpu_test.bus.load(rd + offset, 8), val & std::u8::MAX as u32);
+    }
     #[test]
-    fn test_exec_sh() {}
+    fn test_exec_sh() {
+        let mut cpu_test = cpu::CPU::new();
+        let offset = 3;
+        let val = (-2 as i32) as u32;
+        let rd = 5 + MEM_BASE;
+        helper::set_register_val(&mut cpu_test, 29, rd as i32);
+        helper::set_register_val(&mut cpu_test, 30, val as i32);
+        // sh x30, x29, 3
+        let instr: u32 = helper::set_s_type_instruction(offset as i16, 30, 29, SH as u8);
+        cpu::exec_sh(&mut cpu_test, instr);
+        assert_eq!(
+            cpu_test.bus.load(rd + offset, 16),
+            val & std::u16::MAX as u32
+        );
+    }
     #[test]
-    fn test_exec_sw() {}
+    fn test_exec_sw() {
+        let mut cpu_test = cpu::CPU::new();
+        let offset = 3;
+        let val = (-2 as i32) as u32;
+        let rd = 5 + MEM_BASE;
+        helper::set_register_val(&mut cpu_test, 29, rd as i32);
+        helper::set_register_val(&mut cpu_test, 30, val as i32);
+        // sw x30, x29, 3
+        let instr: u32 = helper::set_s_type_instruction(offset as i16, 30, 29, SW as u8);
+        cpu::exec_sw(&mut cpu_test, instr);
+        assert_eq!(cpu_test.bus.load(rd + offset, 32), val);
+    }
     #[test]
     fn test_exec_addi() {
         let mut cpu_test = cpu::CPU::new();
diff --git a/tests/helper.rs b/tests/helper.rs
index cb79330..3e4c260 100644
--- a/tests/helper.rs
+++ b/tests/helper.rs
@@ -1,6 +1,6 @@
 use emurv::{
     cpu,
-    opcode::{ADDI, B_TYPE, I_TYPE, LOAD, LUI, R_TYPE},
+    opcode::{ADDI, B_TYPE, I_TYPE, LOAD, LUI, R_TYPE, S_TYPE},
 };
 
 pub fn set_r_type_instruction(rs2: u8, rs1: u8, funct3: u8, rd: u8) -> u32 {
@@ -21,6 +21,18 @@ pub fn set_i_type_instruction(imm: i16, rs1: u8, funct3: u8, rd: u8) -> u32 {
         | ((I_TYPE as u32) & 0x7f);
 }
 
+pub fn set_s_type_instruction(imm: i16, rs2: u8, rs1: u8, funct3: u8) -> u32 {
+    let imm11_5 = (imm & 0x7f0) as u32;
+    let imm4_0 = (imm & 0x1f) as u32;
+
+    return (imm11_5 << 20)
+        | ((rs2 as u32 & 0x1f) << 20)
+        | ((rs1 as u32 & 0x1f) << 15)
+        | ((funct3 as u32 & 0x7) << 12)
+        | (imm4_0 << 7)
+        | ((S_TYPE as u32) & 0x7f);
+}
+
 pub fn set_load_type_instruction(imm: i16, rs1: u8, funct3: u8, rd: u8) -> u32 {
     // |31-20|19-15|14-12|11-7|6-0|
     return ((imm as u32 & 0xfff) << 20)