PASM reconstruction

Comments

• Dave Hein Posts: 6,347

  2011-02-01 13:43 edited 2011-02-01 13:43

  The two longs are Spin bytecodes for cognew and return. This translates as follows:
  

  34    ldlim1   'Load a value of -1 to the stack
  c7 08 lalo 8   'Load an object address with an offset of 8
  35    ldl0     'Load a value of zero to the stack
  2c    coginit  'Perform a coginit using the 3 values on the stack
  32    ret      'Return
  

  The object offset for your PASM program is 8, even though your PASM program is at the beginning of the DAT area. This is because the method table is in the first 8 bytes of your object. The parameter of -1 for coginit says that it should use the next available cog (i.e. cognew).
  
  Dave
• Bocephus Posts: 58

  2011-02-01 15:48 edited 2011-02-01 15:48

  Very helpful, thanks Dave. I'll search the forum for the spin bytecodes. Will I find a list of the mnemonics, such as ldln1 and lalo 8, in a forum search as well?
• Dave Hein Posts: 6,347

  2011-02-01 16:14 edited 2011-02-01 16:14

  There are no official mnemonics for the spin bytecodes. BST provides a description of the bytecodes in its compiler listing, but it doesn't use mnemonics. I am developing a bytecode assembler (spasm) and a spin simulator (SpinSim), and I needed mnemonics, so I defined them. There have been other attempts to define spin bytecode mnemonics, but I felt they weren't concise enough. I'll post a description of the codes when I get home this evening.
  
  Dave
• Dave Hein Posts: 6,347

  2011-02-01 20:20 edited 2011-02-01 20:20

  Bocephus,
  
  The attached file lists the Spin bytecode mnemonics with some descriptions. I need to work more on this document. The memory mnemonics have the following format:
  
  {ld, st, la, ex}{l, m, w, b}{l, v, o, a, i}{c, x, 0, 1, m1}
  
  Each field has the following meanings:
  
  {ld, st, la, ex} - Load, Store, Load Address, Execute
  {l, m, w, b} - Long, Medium, Word, Byte (Medium is 3 bytes)
  {l, v, o, a, i} - Local offset, Var offset, Object offset, Absolute address, Immediate
  {c, x, 0, 1, m1} - Compact, Indexed, zero, one, minus one
  
  The third variable on a the stack would be loaded with "ldllc 12" or "ldll 12" The ldllc generates a one-byte code and the ldll generates two bytes. An indexed byte in the DAT area would be stored with "stbox $111".
  
  The "ex" memory instruction perform an additional operation on a memory location, and can optionally load the result onto the stack. The additional instruction is one of the 32 math operations or it could pre or post decrement or increment, sign extension or the random function. An example of an ex instruction would be "exllc 12 preinc load", which would increment stack variable number 3 and load the result on the stack.
  
  Dave

  txt

  txt

  opcodes.txt

  8K

  opcodes.txt 8.1K
• Bocephus Posts: 58

  2011-02-01 23:06 edited 2011-02-01 23:06

  Dave, you have some great projects going there. I fiddled with BST and it is nice as well.
  
  Your mnemonics format seems logical, and I appreciate the explanation along with the opcodes text.
  
  After searching the forum for some time, I see I am well behind the curve, but I think the fog is slowly lifting.
• Bocephus Posts: 58

  2011-02-04 01:33 edited 2011-02-04 01:33

  I got the program to read the binary file and regenerate compilable source. Thanks for the help Dave!
  

  CON
          _clkmode = xtal1 + pll16x
          _clkfreq = 80000000
  
  PUB main
          cognew(@_asm_, 0)
  
  DAT
                  ORG
  
  _asm_           OR      CTRA,   DAT_0   
                  CALL    #FUN_0  
                  MOV     FRQA,   DAT_6   
                  OR      DIRA,   DAT_3   
                  MOV     VAR_1,  #1      
                  SHL     VAR_1,  #16     
                  MOV     VAR_2,  CNT     
                  ADD     VAR_2,  DAT_5   
  
  :LAB_0          OR      DIRA,   DAT_1   
                  WAITCNT VAR_2,  DAT_5   
                  AND     DAT_2,  INA     WZ,NR
                  ANDN    DIRA,   DAT_1   
          IF_NZ   JMP     #:LAB_0 
                  ADD     VAR_0,  VAR_1   
                  AND     VAR_0,  DAT_4   WC,NR
          IF_C    MOV     VAR_0,  #0      
          IF_NC   ANDN    OUTA,   DAT_3   
          IF_NC   OR      OUTA,   VAR_0   
                  MOV     VAR_3,  #VSCL   
  
  :LAB_1          WAITCNT VAR_2,  DAT_5   
                  DJNZ    VAR_3,  #:LAB_1 
                  JMP     #:LAB_0 
  
  FUN_0           SHL     DAT_8,  #1      
                  MOV     VAR_1,  #32     
  
  :LAB_2          SHL     DAT_6,  #1      
                  CMPSUB  DAT_8,  DAT_7   WC
          IF_C    ADD     DAT_6,  #1      
                  SHL     DAT_8,  #1      
                  DJNZ    VAR_1,  #:LAB_2 
  
  FUN_0_RET       RET                     
  
                  DAT_0   LONG    268435460       
                  DAT_1   LONG    16      
                  DAT_2   LONG    32      
                  DAT_3   LONG    16711680        
                  DAT_4   LONG    16777216        
                  DAT_5   LONG    32000   
                  DAT_6   LONG    0       
                  DAT_7   LONG    80000000        
                  DAT_8   LONG    38000   
                  VAR_0   RES     1       
                  VAR_1   RES     1       
                  VAR_2   RES     1       
                  VAR_3   RES     1       
  
                  FIT