diff --git a/hbvm/src/bytecode.rs b/hbvm/src/bytecode.rs
index a9770c6..3c2014f 100644
--- a/hbvm/src/bytecode.rs
+++ b/hbvm/src/bytecode.rs
@@ -9,47 +9,56 @@ macro_rules! constmod {
 }
 
 constmod!(pub opcode(u8) {
-    NOP = 0, // N
-    ADD = 1, // RRR
-    SUB = 2, // RRR
-    MUL = 3, // RRR
-    DIV = 4, // RRR
-    REM = 5, // RRR
-    AND = 6, // RRR
-    OR  = 7, // RRR
-    XOR = 8, // RRR
-    NOT = 9, // RR
+    NOP = 0, // N; Do nothing
+    ADD = 1, // RRR; #0 ← #1 + #2
+    SUB = 2, // RRR; #0 ← #1 - #2
+    MUL = 3, // RRR; #0 ← #1 × #2
+    DIV = 4, // RRR; #0 ← #1 ÷ #2
+    REM = 5, // RRR; #0 ← #1 % #2
+    AND = 6, // RRR; #0 ← #1 & #2
+    OR  = 7, // RRR; #0 ← #1 | #2
+    XOR = 8, // RRR; #0 ← #1 ^ #2
+    NOT = 9, // RR;  #0 ← !#1
 
     // TODO: Add instruction for integer and float
     // reg ← reg + imm instructions
 
-    ADDF = 10, // RRR
-    SUBF = 11, // RRR
-    MULF = 12, // RRR
-    DIVF = 13, // RRR
+    ADDF = 10, // RRR; #0 ← #1 +. #2
+    SUBF = 11, // RRR; #0 ← #1 +. #2
+    MULF = 12, // RRR; #0 ← #1 +. #2
+    DIVF = 13, // RRR; #0 ← #1 +. #2
 
-    LI = 14, // RI
-    LD = 15, // RI
-    ST = 16, // RI
+    CP = 14, // RR;  Copy #0 ← #1
+    LI = 15, // RI;  Load immediate, #0 ← imm #1
+    LB = 16, // RRI; Load byte (8 bits), #0 ← [#1 + imm #2]
+    LD = 17, // RRI; Load doublet (16 bits)
+    LQ = 18, // RRI; Load quadlet (32 bits)
+    LO = 19, // RRI; Load octlet (64 bits)
+    SB = 20, // RRI; Store byte, [#1 + imm #2] ← #0
+    SD = 21, // RRI; Store doublet
+    SQ = 22, // RRI; Store quadlet
+    SO = 23, // RRI; Store octlet
 
-    MAPPAGE   = 17, // ?
-    UNMAPPAGE = 18, // ?
+    PAGEMAP   = 24, // ?; Map a page
+    PAGEUNMAP = 25, // ?; Unmap a page
+    PAGEMP    = 26, // ?; Page modify protection flags
 
-    JMP     = 100, // I
-    JMPCOND = 101, // I
-    RET     = 103, // N
-    ECALL   = 255, // N
+    JMP     = 100, // I; Unconditional jump
+    JMPCOND = 101, // ?; Conditional jump
+    RET     = 103, // N; Return
+    ECALL   = 255, // N; Issue system call
 });
 
 #[repr(packed)] pub struct ParamRRR(pub u8, pub u8, pub u8);
+#[repr(packed)] pub struct ParamRRI(pub u8, pub u8, pub u64);
 #[repr(packed)] pub struct ParamRR(pub u8, pub u8);
-
 #[repr(packed)] pub struct ParamRI(pub u8, pub u64);
 
 /// # Safety
 /// TODO.
 pub unsafe trait OpParam {}
 unsafe impl OpParam for ParamRRR {}
+unsafe impl OpParam for ParamRRI {}
 unsafe impl OpParam for ParamRR {}
 unsafe impl OpParam for ParamRI {}
 unsafe impl OpParam for u64 {}
diff --git a/hbvm/src/validate.rs b/hbvm/src/validate.rs
index d6aacaa..7a1c267 100644
--- a/hbvm/src/validate.rs
+++ b/hbvm/src/validate.rs
@@ -48,7 +48,7 @@ pub fn validate(mut program: &[u8]) -> Result<(), Error> {
                 rest
             }
             // RR
-            [NOT, _, _, rest @ ..] => {
+            [NOT | CP, _, _, rest @ ..] => {
                 if let Some(n) = reg(&program[1..=2]) {
                     bail!(InvalidRegister, start, program, n + 1)
                 }
@@ -61,7 +61,7 @@ pub fn validate(mut program: &[u8]) -> Result<(), Error> {
                 }
                 rest
             }
-            [LD | ST, ..] => bail!(Unimplemented, start, program),
+            [LD..=SO, ..] => bail!(Unimplemented, start, program),
             _ => bail!(InvalidInstruction, start, program),
         }
     }
diff --git a/hbvm/src/vm/mod.rs b/hbvm/src/vm/mod.rs
index 0275558..57db9f5 100644
--- a/hbvm/src/vm/mod.rs
+++ b/hbvm/src/vm/mod.rs
@@ -75,11 +75,15 @@ impl<'a> Vm<'a> {
                     SUBF => binary_op!(self, float, ops::Sub::sub),
                     MULF => binary_op!(self, float, ops::Mul::mul),
                     DIVF => binary_op!(self, float, ops::Div::div),
+                    CP => {
+                        let param = param!(self, ParamRR);
+                        *self.reg_mut(param.0) = *self.reg(param.1);
+                    }
                     LI => {
                         let param = param!(self, ParamRI);
                         *self.reg_mut(param.0) = param.1.into();
                     }
-                    // TODO: LD, ST
+                    // TODO: Loads and stores
                     JMP => {
                         self.pc =
                             self.program.as_ptr().add(self.pc + 1).cast::<u64>().read() as usize;