opcodes/arm: use '@' consistently for the comment character

Looking at the ARM disassembler output, every comment seems to start
with a ';' character, so I assumed this was the correct character to
start an assembler comment.

I then spotted a couple of places where there was no ';', but instead,
just a '@' character.  I thought that this was a case of a missing
';', and proposed a patch to add the missing ';' characters.

Turns out I was wrong, '@' is actually the ARM assembler comment
character, while ';' is the statement separator.  Thus this:

    nop    ;@ comment

is two statements, the first is the 'nop' instruction, while the
second contains no instructions, just the '@ comment' comment text.

This:

    nop    @ comment

is a single 'nop' instruction followed by a comment.  And finally,
this:

    nop    ; comment

is two statements, the first contains the 'nop' instruction, while the
second contains the instruction 'comment', which obviously isn't
actually an instruction at all.

Why this matters is that, in the next commit, I would like to add
libopcodes syntax styling support for ARM.

The question then is how should the disassembler style the three cases
above?

As '@' is the actual comment start character then clearly the '@' and
anything after it can be styled as a comment.  But what about ';' in
the second example?  Style as text?  Style as a comment?

And the third example is even harder, what about the 'comment' text?
Style as an instruction mnemonic?  Style as text?  Style as a comment?

I think the only sensible answer is to move the disassembler to use
'@' consistently as its comment character, and remove all the uses of
';'.

Then, in the next commit, it's obvious what to do.

There's obviously a *lot* of tests that get updated by this commit,
the only actual code changes are in opcodes/arm-dis.c.

1 files changed, 7 insertions, 7 deletions

diff --git a/ld/testsuite/ld-arm/tls-gdesc-neg.d b/ld/testsuite/ld-arm/tls-gdesc-neg.d
index f4debb1..a09e158 100644
--- a/ld/testsuite/ld-arm/tls-gdesc-neg.d
+++ b/ld/testsuite/ld-arm/tls-gdesc-neg.d
@@ -7,17 +7,17 @@ start address 0x[0-9a-f]+
 Disassembly of section .plt:
 
 00008164 <.plt>:
-    8164:	e52de004 	push	{lr}		; .*
-    8168:	e59fe004 	ldr	lr, \[pc, #4\]	; .*
+    8164:	e52de004 	push	{lr}		@ .*
+    8168:	e59fe004 	ldr	lr, \[pc, #4\]	@ .*
     816c:	e08fe00e 	add	lr, pc, lr
     8170:	e5bef008 	ldr	pc, \[lr, #8\]!
     8174:	000080d8 	.word	0x000080d8
     8178:	e08e0000 	add	r0, lr, r0
     817c:	e5901004 	ldr	r1, \[r0, #4\]
     8180:	e12fff11 	bx	r1
-    8184:	e52d2004 	push	{r2}		; .*
-    8188:	e59f200c 	ldr	r2, \[pc, #12\]	; .*
-    818c:	e59f100c 	ldr	r1, \[pc, #12\]	; .*
+    8184:	e52d2004 	push	{r2}		@ .*
+    8188:	e59f200c 	ldr	r2, \[pc, #12\]	@ .*
+    818c:	e59f100c 	ldr	r1, \[pc, #12\]	@ .*
     8190:	e79f2002 	ldr	r2, \[pc, r2\]
     8194:	e081100f 	add	r1, r1, pc
     8198:	e12fff12 	bx	r2
@@ -27,13 +27,13 @@ Disassembly of section .plt:
 Disassembly of section .text:
 
 000081a4 <foo>:
-    81a4:	e59f0000 	ldr	r0, \[pc\]	; .*
+    81a4:	e59f0000 	ldr	r0, \[pc\]	@ .*
     81a8:	ea000000 	b	81b0 <foo\+0xc>
     81ac:	000080a4 	.word	0x000080a4
     81b0:	fafffff0 	blx	8178 <.plt\+0x14>
 
 000081b4 <bar>:
-    81b4:	4800      	ldr	r0, \[pc, #0\]	; .*
+    81b4:	4800      	ldr	r0, \[pc, #0\]	@ .*
     81b6:	e001      	b.n	81bc <bar\+0x8>
     81b8:	00008097 	.word	0x00008097
     81bc:	f7ff efdc 	blx	8178 <.plt\+0x14>