[fpc-devel] Some Opcodes missing in internal assembler for mips32r2

Michael Ring mail at michael-ring.org
Tue May 28 21:40:32 CEST 2013

Thank you Sergei, I will have a look at that code.

I have just finished inserting ugly .long 0xxxxxx statements in my code 
to hardcode the missing pieces, I am really glad you answered ;-) ;-)

I also found some statements that get translated wrong:

and     $a0,$a0,0

and     $a1,$a1,0

li      $t2,0

the statements are missing the last param in the generated assembler file:

pic32mx1xxfxxxb.s:87: Error: absolute expression required `li $t2,'
pic32mx1xxfxxxb.s:102: Error: absolute expression required `and $a0,$a0,'

I guess this needs to be fixed in mips/aasmcpu.pas


Am 28.05.13 21:31, schrieb Sergei Gorelkin:
> 28.05.2013 22:50, Michael Ring пишет:
>> I am currently writing/porting startup code for the pic32 chips, the 
>> inline assembler of fpc seems
>> to lack support for some opcodes, any idea how I can workarround this?
>> With grep I found for example mtc1 in opcode.inc, but mtc0 is 
>> missing, this opcode is important for
>> the initialization of the pic32 chips.
>> Is it easy to implement those missing op-codes in the internal 
>> assembler, if yes, could some
>> fpc-crack give me a hint on what to change where?
> Since assembler reader for MIPS is at a very early stage, adding 
> opcodes isn't difficult:
> 1) Add the opcode enum to mips/opcode.inc and its string 
> representation to mips/strinst.inc.
> 2) For 'ext' and 'ins' you'll need to add the appropriate overloaded 
> constructor to taicpu class in mips/aasmcpu.pas (they are going to be 
> the first opcodes with 4 operands)
> 3) Modify taicpu.spilling_get_operation_type method (in 
> mips/aasmcpu.pas) to reflect which operands are read/written by newly 
> added opcodes.
> A more difficult task will be to restrict opcodes to CPU type and 
> operands to opcodes.
>> Those are the missing opcodes:
>> beqz
>> ehb
>> ext
>> ins
>> mfc0
>> mtc0
>> sdbbp
>> wrpgpr
> Note that 'beqz reg,label' is just a shorter representation of 'beq  
> reg,$zero,label', not a separate opcode (unlike bgtz/bltz/blez/bgez 
> which are really missing).
> Regards,
> Sergei
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