diff --git a/hbbytecode/src/lib.rs b/hbbytecode/src/lib.rs
index a4f09b45..78298bb1 100644
--- a/hbbytecode/src/lib.rs
+++ b/hbbytecode/src/lib.rs
@@ -35,40 +35,40 @@ constmod!(pub opcode(u8) {
     NEG  = 13, "BB; #0 ← ~#1";
     NOT  = 14, "BB; #0 ← !#1";
 
-    ADDI  = 18, "BBD; #0 ← #1 + imm #2";
-    MULI  = 19, "BBD; #0 ← #1 × imm #2";
-    ANDI  = 20, "BBD; #0 ← #1 & imm #2";
-    ORI   = 21, "BBD; #0 ← #1 | imm #2";
-    XORI  = 22, "BBD; #0 ← #1 ^ imm #2";
-    SLI   = 23, "BBD; #0 ← #1 « imm #2";
-    SRI   = 24, "BBD; #0 ← #1 » imm #2";
-    SRSI  = 25, "BBD; #0 ← #1 » imm #2 (signed)";
-    CMPI  = 26, "BBD; #0 ← #1 <=> imm #2";
-    CMPUI = 27, "BBD; #0 ← #1 <=> imm #2 (unsigned)";
+    ADDI  = 15, "BBD; #0 ← #1 + imm #2";
+    MULI  = 16, "BBD; #0 ← #1 × imm #2";
+    ANDI  = 17, "BBD; #0 ← #1 & imm #2";
+    ORI   = 18, "BBD; #0 ← #1 | imm #2";
+    XORI  = 19, "BBD; #0 ← #1 ^ imm #2";
+    SLI   = 20, "BBD; #0 ← #1 « imm #2";
+    SRI   = 21, "BBD; #0 ← #1 » imm #2";
+    SRSI  = 22, "BBD; #0 ← #1 » imm #2 (signed)";
+    CMPI  = 23, "BBD; #0 ← #1 <=> imm #2";
+    CMPUI = 24, "BBD; #0 ← #1 <=> imm #2 (unsigned)";
 
-    CP  = 28, "BB; Copy #0 ← #1";
-    SWA = 29, "BB; Swap #0 and #1";
-    LI  = 30, "BD; #0 ← imm #1";
-    LD  = 31, "BBDB; #0 ← [#1 + imm #3], imm #4 bytes, overflowing";
-    ST  = 32, "BBDB; [#1 + imm #3] ← #0, imm #4 bytes, overflowing";
-    BMC = 33, "BBD; [#0] ← [#1], imm #2 bytes";
-    BRC = 34, "BBB; #0 ← #1, imm #2 registers";
+    CP  = 25, "BB; Copy #0 ← #1";
+    SWA = 26, "BB; Swap #0 and #1";
+    LI  = 27, "BD; #0 ← imm #1";
+    LD  = 28, "BBDB; #0 ← [#1 + imm #3], imm #4 bytes, overflowing";
+    ST  = 29, "BBDB; [#1 + imm #3] ← #0, imm #4 bytes, overflowing";
+    BMC = 30, "BBD; [#0] ← [#1], imm #2 bytes";
+    BRC = 31, "BBB; #0 ← #1, imm #2 registers";
 
-    JMP   = 35, "BD;  Unconditional jump [#0 + imm #1]";
-    JEQ   = 36, "BBD; if #0 = #1 → jump imm #2";
-    JNE   = 37, "BBD; if #0 ≠ #1 → jump imm #2";
-    JLT   = 38, "BBD; if #0 < #1 → jump imm #2";
-    JGT   = 39, "BBD; if #0 > #1 → jump imm #2";
-    JLTU  = 40, "BBD; if #0 < #1 → jump imm #2 (unsigned)";
-    JGTU  = 41, "BBD; if #0 > #1 → jump imm #2 (unsigned)";
-    ECALL = 42, "N; Issue system call";
+    JMP   = 32, "BD;  Unconditional jump [#0 + imm #1]";
+    JEQ   = 33, "BBD; if #0 = #1 → jump imm #2";
+    JNE   = 34, "BBD; if #0 ≠ #1 → jump imm #2";
+    JLT   = 35, "BBD; if #0 < #1 → jump imm #2";
+    JGT   = 36, "BBD; if #0 > #1 → jump imm #2";
+    JLTU  = 37, "BBD; if #0 < #1 → jump imm #2 (unsigned)";
+    JGTU  = 38, "BBD; if #0 > #1 → jump imm #2 (unsigned)";
+    ECALL = 39, "N; Issue system call";
 
-    ADDF  = 43, "BBB; #0 ← #1 +. #2";
-    MULF  = 44, "BBB; #0 ← #1 +. #2";
-    DIRF  = 45, "BBBB; #0 ← #2 / #3, #1 ← #2 % #3";
+    ADDF  = 40, "BBB; #0 ← #1 +. #2";
+    MULF  = 41, "BBB; #0 ← #1 +. #2";
+    DIRF  = 42, "BBBB; #0 ← #2 / #3, #1 ← #2 % #3";
 
-    ADDFI = 46, "BBD; #0 ← #1 +. imm #2";
-    MULFI = 47, "BBD; #0 ← #1 *. imm #2";
+    ADDFI = 43, "BBD; #0 ← #1 +. imm #2";
+    MULFI = 44, "BBD; #0 ← #1 *. imm #2";
 });
 
 #[repr(packed)]
diff --git a/spec.md b/spec.md
index b8d73138..3d9ff087 100644
--- a/spec.md
+++ b/spec.md
@@ -93,22 +93,22 @@
 
 | Opcode | Name |         Action          |
 |:------:|:----:|:-----------------------:|
-|   18   | ADDI |    Wrapping addition    |
-|   19   | MULI |  Wrapping subtraction   |
-|   20   | ANDI |         Bitand          |
-|   21   | ORI  |          Bitor          |
-|   22   | XORI |         Bitxor          |
-|   23   | SLI  | Unsigned left bitshift  |
-|   24   | SRI  | Unsigned right bitshift |
-|   25   | SRSI |  Signed right bitshift  |
+|   15   | ADDI |    Wrapping addition    |
+|   16   | MULI |  Wrapping subtraction   |
+|   17   | ANDI |         Bitand          |
+|   18   | ORI  |          Bitor          |
+|   19   | XORI |         Bitxor          |
+|   20   | SLI  | Unsigned left bitshift  |
+|   21   | SRI  | Unsigned right bitshift |
+|   22   | SRSI |  Signed right bitshift  |
 
 ### Comparsion
 - Comparsion is the same as when RRR type
 
 | Opcode | Name  |       Action        |
 |:------:|:-----:|:-------------------:|
-|   26   | CMPI  |  Signed comparsion  |
-|   27   | CMPUI | Unsigned comparsion |
+|   23   | CMPI  |  Signed comparsion  |
+|   24   | CMPUI | Unsigned comparsion |
 
 ## Register value set / copy
 
@@ -118,7 +118,7 @@
 
 | Opcode | Name | Action |
 |:------:|:----:|:------:|
-|   28   |  CP  |  Copy  |
+|   25   |  CP  |  Copy  |
 
 ### Swap
 - Type BB
@@ -126,7 +126,7 @@
 
 | Opcode | Name | Action |
 |:------:|:----:|:------:|
-|   29   | SWA  |  Swap  |
+|   26   | SWA  |  Swap  |
 
 ### Load immediate
 - Type BD
@@ -134,7 +134,7 @@
 
 | Opcode | Name |     Action     |
 |:------:|:----:|:--------------:|
-|   30   |  LI  | Load immediate |
+|   27   |  LI  | Load immediate |
 
 ## Memory operations
 - Type BBDH
@@ -143,8 +143,8 @@
 ### Load / Store
 | Opcode | Name |                 Action                  |
 |:------:|:----:|:---------------------------------------:|
-|   31   |  LD  | `#0 ← [#1 + imm #3], copy imm #4 bytes` |
-|   32   |  ST  | `[#1 + imm #3] ← #0, copy imm #4 bytes` |
+|   28   |  LD  | `#0 ← [#1 + imm #3], copy imm #4 bytes` |
+|   29   |  ST  | `[#1 + imm #3] ← #0, copy imm #4 bytes` |
 
 ## Block copy
 - Block copy source and target can overlap
@@ -154,7 +154,7 @@
 
 | Opcode | Name |              Action              |
 |:------:|:----:|:--------------------------------:|
-|   33   | BMC  | `[#0] ← [#1], copy imm #2 bytes` |
+|   30   | BMC  | `[#0] ← [#1], copy imm #2 bytes` |
 
 ### Register copy
 - Type BBB
@@ -162,7 +162,7 @@
 
 | Opcode | Name |              Action              |
 |:------:|:----:|:--------------------------------:|
-|   34   | BRC  | `#0 ← #1, copy imm #2 registers` |
+|   31   | BRC  | `#0 ← #1, copy imm #2 registers` |
 
 ## Control flow
 
@@ -171,7 +171,7 @@
 
 | Opcode | Name |        Action         |
 |:------:|:----:|:---------------------:|
-|   35   | JMP  | Jump at `#0 + imm #1` |
+|   32   | JMP  | Jump at `#0 + imm #1` |
 
 ### Conditional jumps
 - Type BBD
@@ -179,19 +179,19 @@
 
 | Opcode | Name |  Comparsion  |
 |:------:|:----:|:------------:|
-|   36   | JEQ  |      =       |
-|   37   | JNE  |      ≠       |
-|   38   | JLT  |  < (signed)  |
-|   39   | JGT  |  > (signed)  |
-|   40   | JLTU | < (unsigned) |
-|   41   | JGTU | > (unsigned) |
+|   33   | JEQ  |      =       |
+|   34   | JNE  |      ≠       |
+|   35   | JLT  |  < (signed)  |
+|   36   | JGT  |  > (signed)  |
+|   37   | JLTU | < (unsigned) |
+|   38   | JGTU | > (unsigned) |
 
 ### Environment call
 - Type N
 
 | Opcode | Name  |                Action                 |
 |:------:|:-----:|:-------------------------------------:|
-|   42   | ECALL | Cause an trap to the host environment |
+|   39   | ECALL | Cause an trap to the host environment |
 
 ## Floating point operations
 - Type BBB
@@ -199,15 +199,15 @@
 
 | Opcode | Name |     Action     |
 |:------:|:----:|:--------------:|
-|   43   | ADDF |    Addition    |
-|   44   | MULF | Multiplication |
+|   40   | ADDF |    Addition    |
+|   41   | MULF | Multiplication |
 
 ### Division-remainder
 - Type BBBB
 
 | Opcode | Name |                 Action                 |
 |:------:|:----:|:--------------------------------------:|
-|   45   | DIRF | Same flow applies as for integer `DIR` |
+|   42   | DIRF | Same flow applies as for integer `DIR` |
 
 ## Floating point immediate operations
 - Type BBD
@@ -215,8 +215,8 @@
 
 | Opcode | Name  |     Action     |
 |:------:|:-----:|:--------------:|
-|   46   | ADDFI |    Addition    |
-|   47   | MULFI | Multiplication |
+|   43   | ADDFI |    Addition    |
+|   44   | MULFI | Multiplication |
 
 # Registers
 - There is 255 registers + one zero register (with index 0)