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

Michael Ring mail at michael-ring.org
Tue Jun 18 12:24:46 CEST 2013

I did have a look at mips-opc.c in binutils, this looks easy to parse, I 
will give this a try, thank you for the hint!

I will come back to you with a 2nd version, looks like a nice task to 
complete while sitting in the train....


Am 17.06.13 08:12, schrieb Sergei Gorelkin:
> 16.06.2013 22:17, Michael Ring пишет:
>> I have now browsed through the current mips documentation and have 
>> created a file that includes all
>> opcodes, the version they are first in (starting with mips32) and a 
>> small comment what the mnemonic
>> does.
>> This file is attached to this mail.
> The problem here is that MIPS32 is not the first, but fifth version of 
> MIPS instruction sets, preceded by MIPS I, MIPS II, MIPS III and MIPS 
> IV. Currently there is no separation between instructions sets in 
> compiler sources, but they need to appear one day. MIPS32 
> documentation is not correct in this respect, as it says e.g. that ADD 
> is first supported by MIPS32, while it is actually MIPS I instruction.
> The most accurate source is probably the GNU Opcode library, which is 
> part of binutils.
>> Out of this file it is easy to create both compiler/mips/strinst.inc 
>> and compiler/mips/opcode.inc.
>> Now I am looking for additional lines that I will need to add to this 
>> file, to find out what is
>> necessary I have created a list of mnemonics that exist only in the 
>> original opcode.inc file (see
>> later)
>> there are a number of entries in the form xxx64xxx and xxx32, xxxg 
>> and dxxx, all those do not seem
>> to be valid for mips32 & up, where do those come from and which of 
>> those do I need to add?
> xxx64xxx and xxxg are likely subject for removal, I've no idea where 
> they came from. dxxx and xxx32 are MIPS III instructions, as well as 
> sdr,sdl,lwu and alike. A lot of other stuff (la, li, neg, mulo, seq, 
> etc.) are macros that are expanded into several instructions.
>> There's one very strange entry in opcode.inc: 'b '
>> there is also 'b', is it necessary to have 'b ' ?
> The codegenerator and optimizer expect conditional and unconditional 
> branches to have distinct opcodes, this strange construction provides 
> that.
> Regards,
> Sergei
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