Sorry, where is oplook, buildop and asmout? On Wednesday, November 30, 2016 at 7:43:25 AM UTC+11, Aram Hăvărneanu wrote: > > On Tue, Nov 29, 2016 at 8:59 PM, matt <matthew....@gmail.com <javascript:>> > wrote: > > Where in the source code does it map say MOVBU.P to ldrb post increment? > > It's complicated, there's no trivial easily-visible mapping (although > for this one instruction the actual concrete mapping chosen is > probably trivial), there's relatively complex code that decides what > to do with an instruction like MOVBU.P. Look in oplook, buildop and > asmout. > > However, for the vast majority of instruction that still doesn't > actually say "ldrb post increment" anywhere in the code. You just have > to follow the code and functions like oprrr, opmvl, etc, and then read > the bits. > > It's much easier to use objdump if you are unsure of a particular > instruction. > > However, you rarely have to use objdump. Mostly only to add new > instructions. Go uses consistent calling convention and syntax between > architectures, and a large class of consistent pseudo-instructions > like MOVW, MOVD, etc; the only things that vary are the > more-specialized instructions and the name of the register. > > If you need a specialized instruction it's easy. It usually has the > same name as the one from the platform manual (there are exceptions). > > If you don't need specialized instructions, just use generic > instructions with whatever addressing mode that you want. If a > particular address mode is not supported, or a multi-instruction > sequence is not generated for a particular architecture and complex > addressing mode the assembler will complain. You can always know what > code means semantically, so there's no problem. > > Sometimes you want to see the actual generated code without any > pseudo-instructions, when this is the case, just use objdump. > > I understand all this is not ideal, but it really isn't that bad. I > write more assembly than Go these days, and I never have a problem > with the lack of this mapping. > > That being said, for sparc64 there is indeed a much better documented > mapping. > > -- > Aram Hăvărneanu >
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