Shift instructions such LSR, ASR, etc.

I’ve been using Matt Godbolt’s wonderful Compiler Explorer (godbolt.org) with ARM GCC 8.2 to compile short C programs/routines, and copying & pasting the (instantly updating!) assembler code into either the appropriate BBCSDL* IDE, or a !Zap BASIC window in RISC OS. It’s good fun, and it beats writing reams of assembly language (life’s too short, etc.).

However, the compiler (or perhaps a separate, custom disassembler?) likes to generate shift instructions such as LSR, LSRS, ASR, ASRS, etc. which I’m sure is nice, but neither BBCSDL nor (AFAIK) ARM BASIC V’s assembler supports these instructions, which are just synonyms for MOV[S] Rd,Rn,. Is there a way of persuading GCC (or perhaps Compiler Explorer, if that’s what’s doing the actual disassembly) to simply produce the equivalent MOV instructions instead of the aforementioned shift instructions? I’ve already done some Googling – but no joy, and I’ve checked for possibly relevant compiler switches here: https://gcc.gnu.org/onlinedocs/gcc/ARM-Options.html

Perhaps I’ve missed something obvious.

I know it only takes a few seconds to replace a shift instruction with its MOV equivalent, but I’m just trying to save myself some time.

*BBCSDL (http://www.bbcbasic.co.uk/bbcsdl/index.html)

Are you specifying -marm to force ARM output? (i.e not Thumb). I found I ran into problems if I didn’t do that.

If that doesn’t work, it may be that newer versions of GCC have embraced UAL syntax too much and are incapable of producing the original mnemonics.

Yeah, sounds like Thumb. Mind you, this has got me thinking about Basic Assembler Dialects again, which could easily deal with this kind of thing.

Nope – it’s UAL. There’s no obvious mention of it in the release notes, but GCC seems to have embraced UAL syntax/mnemonics for assembly output starting around GCC 6.

https://gcc.godbolt.org/z/4X5u9I

Naturally.

        add     r10, r0, lr, lsl #2
        lsl     fp, r3, #2

sighs