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m68k : why is bra an alias for braw, not jra
- From: "Philippe De Muyter" <phdm at macqel dot be>
- To: binutils mailing list <binutils at sources dot redhat dot com>
- Date: Tue, 21 Mar 2006 11:06:58 +0100 (CET)
- Subject: m68k : why is bra an alias for braw, not jra
All,
In the m68k assembler, I wonder why `bra' and friends are alias for their
`bxxw' counterparts.
It seems to me that if someone needs a word-sized bra insn, (s)he will
use the braw variant.
And if one writes no size specification for a `bra' instruction the assembler
should be free to choose the most efficient way to generate it, i.e.
a `brab' if possible of even a `bral' if needed.
IIRC, that's also what the Motorola assembler did in Motorola's Unix System V.
It is also what `gcc/config/m68k/lb1sf68.asm' expects in gcc. If you look
at this file, you'll see that it is full of `bra', `beq', `bge' etc., where
the intent is clearly to let the assembler decide.
I know that there exists a `jra' or `jbra' keyword, but that's not the
natural way of writing if you write assembler code using your Motorola
reference manual as base.
If no-one objects, I'll submit a patch
Philippe