diff --git a/src/opcode.rs b/src/opcode.rs
index f43841a..1503ac7 100644
--- a/src/opcode.rs
+++ b/src/opcode.rs
@@ -109,7 +109,7 @@ impl fmt::Debug for Opcode {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             Opcode::Call(address) => {
-                write!(f, "CALL\t{:#04x}", address)
+                write!(f, "CALL\t{:#03x}", address)
             }
             Opcode::Clear => {
                 write!(f, "CLS")
@@ -118,100 +118,100 @@ impl fmt::Debug for Opcode {
                 write!(f, "RET")
             }
             Opcode::Goto(address) => {
-                write!(f, "JMP\t{:#04x}", address)
+                write!(f, "JMP\t{:#03x}", address)
             }
             Opcode::CallFunction(address) => {
-                write!(f, "CALL\t{:#04x}", address)
+                write!(f, "CALL\t{:#03x}", address)
             }
             Opcode::SkipEq(register, constant) => {
-                write!(f, "SE\t{:#03x}\t{}", register, constant)
+                write!(f, "SE\tV{:X}\t{}", register, constant)
             }
             Opcode::SkipNEq(register, constant) => {
-                write!(f, "SNE\t{:#03x}\t{}", register, constant)
+                write!(f, "SNE\tV{:X}\t{}", register, constant)
             }
             Opcode::SkipEqReg(first, second) => {
-                write!(f, "SE\t{:#03x}\t{:#03x}", first, second)
+                write!(f, "SE\tV{:X}\tV{:X}", first, second)
             }
             Opcode::Set(register, constant) => {
-                write!(f, "SET\t{:#03x}\t{}", register, constant)
+                write!(f, "SET\tV{:X}\t{}", register, constant)
             }
             Opcode::AddAssign(register, constant) => {
-                write!(f, "ADDA\t{:#03x}\t{}", register, constant)
+                write!(f, "ADDA\tV{:X}\t{}", register, constant)
             }
             Opcode::Copy(to, from) => {
-                write!(f, "SET\t{:#03x}\t{:#03x}", to, from)
+                write!(f, "SET\tV{:X}\tV{:X}", to, from)
             }
             Opcode::Or(first, second) => {
-                write!(f, "OR\t{:#03x}\t{:#03x}", first, second)
+                write!(f, "OR\tV{:X}\tV{:X}", first, second)
             }
             Opcode::And(first, second) => {
-                write!(f, "AND\t{:#03x}\t{:#03x}", first, second)
+                write!(f, "AND\tV{:X}\tV{:X}", first, second)
             }
             Opcode::Xor(first, second) => {
-                write!(f, "XOR\t{:#03x}\t{:#03x}", first, second)
+                write!(f, "XOR\tV{:X}\tV{:X}", first, second)
             }
             Opcode::AddAssignReg(first, second) => {
-                write!(f, "ADDA\t{:#03x}\t{:#03x}", first, second)
+                write!(f, "ADDA\tV{:X}\tV{:X}", first, second)
             }
             Opcode::SubAssignReg(first, second) => {
-                write!(f, "SUBA\t{:#03x}\t{:#03x}", first, second)
+                write!(f, "SUBA\tV{:X}\tV{:X}", first, second)
             }
             Opcode::ShiftRight(first, second) => {
-                write!(f, "SHR\t{:#03x}\t{:#03x}", first, second)
+                write!(f, "SHR\tV{:X}\tV{:X}", first, second)
             }
             Opcode::Subtract(first, second) => {
-                write!(f, "SUB\t{:#03x}\t{:#03x}", first, second)
+                write!(f, "SUB\tV{:X}\tV{:X}", first, second)
             }
             Opcode::ShiftLeft(first, second) => {
-                write!(f, "SHL\t{:#03x}\t{:#03x}", first, second)
+                write!(f, "SHL\tV{:X}\tV{:X}", first, second)
             }
             Opcode::SkipNEqReg(first, second) => {
-                write!(f, "SNE\t{:#03x}\t{:#03x}", first, second)
+                write!(f, "SNE\tV{:X}\tV{:X}", first, second)
             }
             Opcode::SetAddressReg(address) => {
-                write!(f, "SET\tI\t{:#04x}", address)
+                write!(f, "SET\tI\t{:#03x}", address)
             }
             Opcode::JumpOffset(constant) => {
                 write!(f, "OFF\t{}", constant)
             }
             Opcode::SetRand(register, constant) => {
-                write!(f, "RND\t{:#03x}\t{}", register, constant)
+                write!(f, "RND\tV{:X}\t{}", register, constant)
             }
             Opcode::Draw(first, second, constant) => {
-                write!(f, "DRW\t{:#03x}\t{:#03x}\t{}", first, second, constant)
+                write!(f, "DRW\tV{:X}\tV{:X}\t{}", first, second, constant)
             }
             Opcode::SkipKeyPress(register) => {
-                write!(f, "SKP\t{:#03x}", register)
+                write!(f, "SKP\tV{:X}", register)
             }
             Opcode::SkipNoKeyPress(register) => {
-                write!(f, "SNKP\t{:#03x}", register)
+                write!(f, "SNKP\tV{:X}", register)
             }
             Opcode::StoreDelayTimer(register) => {
-                write!(f, "SET\t{:#03x}\tDELAY", register)
+                write!(f, "SET\tV{:X}\tDELAY", register)
             }
             Opcode::StoreKeypress(register) => {
-                write!(f, "SET\t{:#03x}\tKEY", register)
+                write!(f, "SET\tV{:X}\tKEY", register)
             }
             Opcode::SetDelayTimer(register) => {
-                write!(f, "SET\tDELAY\t{:#03x}", register)
+                write!(f, "SET\tDELAY\tV{:X}", register)
             }
             Opcode::SetSoundTimer(register) => {
-                write!(f, "SET\tSOUND\t{:#03x}", register)
+                write!(f, "SET\tSOUND\tV{:X}", register)
             }
             Opcode::IncrementAddressReg(register) => {
-                write!(f, "ADD\tI\t{:#03x}", register)
+                write!(f, "ADD\tI\tV{:X}", register)
             }
             Opcode::StoreSpriteAddress(register) => {
-                write!(f, "SPRT\t{:#03x}", register)
+                write!(f, "SPRT\tV{:X}", register)
             }
             Opcode::BinaryCodedDecimal(register) => {
-                write!(f, "BCD\t{:#03x}", register)
+                write!(f, "BCD\tV{:X}", register)
             }
             Opcode::Dump(register) => {
-                write!(f, "DUMP\t{:#03x}", register)
+                write!(f, "DUMP\tV{:X}", register)
             }
             Opcode::Load(register) => {
-                write!(f, "LOAD\t{:#03x}", register)
+                write!(f, "LOAD\tV{:X}", register)
             }
         }
     }