diff --git a/.gitignore b/.gitignore
index 2ddd4df..2d807b4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1 @@
-tinyrv
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+tinyriscv
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diff --git a/makefile b/makefile
index b185d36..654ab3b 100644
--- a/makefile
+++ b/makefile
@@ -1,2 +1,2 @@
 default:
-	gcc src/*.c -o tinyrv
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+	gcc src/main.c -o tinyriscv
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diff --git a/src/main.c b/src/main.c
index 7cd0950..2f532d3 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,9 +1,9 @@
 #include <stdint.h>
 
 typedef struct{
-	uint32_t registers[32], pc;
-	uint8_t* memory;
-}tinyrv_cpu;
+	uint32_t regs[32], pc;
+	uint8_t* mem;
+}Cpu;
 
 const uint32_t MEMORY_OFFSET = 0x80000000;
 
@@ -18,62 +18,52 @@ static inline uint32_t select_bits(const uint32_t val, const uint8_t end,
 	return val >> start & (1 << len - 1);
 }
 
-void add(tinyrv_cpu* cpu, ){
-
-	reg_file[rd] = reg_file[rs1] + reg_file[rs2];
-
-}
-
-void R_type(){
+void R_type(const uint8_t func3, const uint8_t func7, uint32_t regs[32], 
+	const uint8_t rd, const uint8_t rs1, const uint8_t rs2){
 
 	switch(func3){
-	case 0x0: // ADD/SUB
-		if(func7 == 0x00) reg_file[rd] = reg_file[rs1] + reg_file[rs2];
-		else if(func7 == 0x20) reg_file[rd] = reg_file[rs1] - reg_file[rs2];
+	case /*ADD/SUB*/ 0x0:
+		if(func7 == /*ADD*/ 0x00) regs[rd] = regs[rs1] + regs[rs2];
+		else if(func7 == /*SUB*/ 0x20) regs[rd] = regs[rs1] - regs[rs2];
 		break;
 
-	case /*SLL*/ 0x1: regs[rd] = regs[rs1] << (regs[rs2] & 0b11111); break;
+	case /*SLL*/ 0x1: regs[rd] = regs[rs1] << (regs[rs2] & 0x1f); break;
 	case /*SLT*/ 0x2: regs[rd] = (int32_t)regs[rs1] < (int32_t)regs[rs2]; break;
 	case /*SLTU*/ 0x3: regs[rd] = regs[rs1] < regs[rs2]; break;
 	case /*XOR*/ 0x4: regs[rd] = regs[rs1] ^ regs[rs2]; break;
-	}
 
+	case /*SRL/SRA*/ 0x5: 
+		if(func7 == /*SRL*/ 0x00) regs[rd] = regs[rs1] >> (regs[rs2] & 0x1f);
+		else if(func7 == /*SRA*/ 0x20) regs[rd] = (int32_t)regs[rs1] >> (regs[rs2] & 0x1f);
+		break;
+
+	case /*OR*/ 0x6: regs[rd] = regs[rs1] | regs[rs2]; break;
+	case /*AND*/ 0x7: regs[rd] = regs[rs1] & regs[rs2]; break;
+	}
 }
 
-void tinyrv_step(tinyrv_cpu* cpu){
+void step(Cpu* cpu){
 	//instruction fetch
-	const uint32_t inst = load32(cpu->memory, cpu->pc);
+	const uint32_t inst = load32(cpu->mem, cpu->pc);
 	cpu->pc += 4;
 
 	//instruction decoding
+	#define opcode select_bits(inst, 6, 0)
+	#define func3 select_bits(inst, 14, 12)
+	#define func7 select_bits(inst, 31, 25)
 	#define rd select_bits(inst, 11, 7)
 	#define rs1 select_bits(inst, 19, 15)
 	#define rs2 select_bits(inst, 24, 20)
 
-	const uint8_t opcode = select_bits(inst, 6, 0);
-
-	switch(func3){
-
-	}
-
-
+	//execute
 	switch(opcode){
-	case LUI:
-
-
-
-	case R_type:{
-			switch(func3){
-			case addsub:
-				switch(func7){
-
-				}
-			}
-		} 		
+	case /*R-type*/ 0x33: R_type(func3, func7, cpu->regs, rd, rs1, rs2); break;
+	//case /*I-type*/ 0x03: I_type(); break;
+	//case /*S-type*/ 0x23: S_type(); break;
+	//case /*B-type*/ 0x63: B_type(); break;
 	}
 }
 
 int main(){
-	tinyrv_cpu cpu;
-	cpu.pc = MEMORY_OFFSET;
-}
+
+}
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