How to create your processors
=============================

Contents
--------
  - add instructions
    - add an negative instruction (`neg r0,r1`)
    - add a special mul (2x+y) instruction (`mul3 r0,r1,r2`)
    - add a register swap instruction (`swap r0,r1`)
    - add a memory copy instruction (`memcpy m(r0),m(r1)`)
  - modify configurations
    - modify a number of registers
    - modify register names
    - modify a link register
    - modify instruction/data memory configurations
  - modify assembler formats
    - modify comment formats
    - modify memory operand formats
    - modify immediate operand formats
    - modify register operand formats



add instructions
----------------

**add an negative instruction (`neg r0,r1`)**

 insert following lines:

 [Language/Pck/Cpu/Instruction.hs] ... internal representation on machine(cpu)
  ~~~haskell
            | NEG   GReg GReg
  ~~~

 [Language/Pck/Cpu/Execution.hs] ... internal behavior on machine(cpu)
  ~~~haskell
  evalStep (NEG   ra rb)    = uniopInst (negate) ra rb
  ~~~

 [Language/Pck/Tool/Assembler.hs] ... assembler format
  ~~~haskell
           <|> inst2 NEG  "neg" greg greg
  ~~~



**add a special mul (2x+y) instruction (`mul3 r0,r1,r2`)**

 insert following lines:

 [Language/Pck/Cpu/Instruction.hs]
  ~~~haskell
            | MUL3  GReg GReg GReg
  ~~~

 [Language/Pck/Cpu/Execution.hs]
  ~~~haskell
  evalStep (MUL3  ra rb rc) = biopInst (\b c -> b*2 + c) ra rb rc
  ~~~

 [Language/Pck/Tool/Assembler.hs]
  ~~~haskell
           <|> inst3 MUL3 "mul3" greg greg greg
  ~~~



**add a register swap instruction (`swap r0,r1`)**

 insert following lines:

 [Language/Pck/Cpu/Instruction.hs]
  ~~~haskell
            | SWAP  GReg GReg
  ~~~

 [Language/Pck/Cpu/Execution.hs]
  ~~~haskell
  evalStep (SWAP  ra rb)    = swap ra rb
  ~~~
  ~~~haskell
  swap :: GReg -> GReg -> EvalCpu ResultStat
  swap ra rb = do va <- readGReg ra
                  vb <- readGReg rb
                  updateGReg ra vb
                  updateGReg rb va
                  incPc
  ~~~

 [Language/Pck/Tool/Assembler.hs]
  ~~~haskell
         <|> inst2 SWAP  "swap" greg greg
  ~~~



**add a memory copy instruction (`memcpy m(r0),m(r1)`)**

 insert following lines:

 [Language/Pck/Cpu/Instruction.hs]
  ~~~haskell
            | MEMCPY GReg GReg
  ~~~

 [Language/Pck/Cpu/Execution.hs]
  ~~~haskell
  evalStep (MEMCPY ra rb)   = memcpy ra rb
  ~~~
  ~~~haskell
  memcpy :: GReg -> GReg -> EvalCpu ResultStat
  memcpy ra rb = do va <- readGReg ra
                    vb <- readGReg rb
                    vm <- readDmem vb
                    updateDmem va vm
                    incPc
  ~~~

 [Language/Pck/Tool/Assembler.hs]
  ~~~haskell
         <|> inst2 MEMCPY "memcpy"  mem mem
  ~~~




modify configurations
---------------------

**modify a number of registers**

 update following line:  

 [Language/Pck/Cpu/Instruction.hs]
  ~~~haskell
  data GReg = R0 | R1 | R2 | R3 | R4 | R5 | R6 | R7 | R8 | R9
  ~~~



**modify register names**

 update following line:  

 [Language/Pck/Cpu/Instruction.hs]
  ~~~haskell
  data GReg = EA | EB | EC | ED
  ~~~



**modify a link register**

 update following line:  

 [Language/Pck/Cpu/Execution.hs]
  ~~~haskell
  linkReg = minBound::GReg  -- default if R0
  ~~~

 to:  

 [Language/Pck/Cpu/Execution.hs]
  ~~~haskell
  linkReg = R7
  ~~~



**modify instruction/data memory configurations**

 update following lines:  

 [Language/Pck/Cpu/Config.hs]
  ~~~haskell
  cpuConfig = CpuConfig
              { cfgStartPc = 0        -- boot(start) address
              , cfgImemStart = 0      -- instruction memory first address
              , cfgImemSize  = 256    -- instruction memory size
              , cfgDmemStart = 0      -- data memory first address
              , cfgDmemSize  = 256    -- data instruction memory size
              }
  ~~~




modify assembler formats
------------------------

**modify comment formats `#`,`/*`,`*/` -> `--`,`{-`,`-}`**

 update following lines:  

 [Language/Pck/Tool/Assembler.hs]
  ~~~haskell
  strCmntLine = "#"
  strCmntRangeBeg = "/*"
  strCmntRangeEnd = "*/"
  ~~~

 to:  

  ~~~haskell
  strCmntLine = "--"
  strCmntRangeBeg = "{-"
  strCmntRangeEnd = "-}"
  ~~~



**modify memory operand formats: `m(r0)`->`[r0]`**

 update following line:  

 [Language/Pck/Tool/Assembler.hs]
  ~~~haskell
  strMemBeg = "m("
  strMemEnd = ")"
  ~~~

 to:  

  ~~~haskell
  strMemBeg = "["
  strMemEnd = "]"
  ~~~



**modify immediate operand formats: `7`->`$7`**

 update following lines:  

 [Language/Pck/Tool/Assembler.hs]
  ~~~haskell
  strImmPref = ""
  ~~~

 to:  

  ~~~haskell
  strImmPref = "$"
  ~~~



**modify register operand formats: `r0`->`%r0`**

 update following lines:  

 [Language/Pck/Tool/Assembler.hs]
  ~~~haskell
  strGRegPref = ""
  ~~~

 to:  

  ~~~haskell
  strGRegPref = "%"
  ~~~