Re: [Patch, microblaze]: Add support of microblaze software single stepping

[Michael Eager <eager@eagerm.com>]

On 07/14/14 03:27, Ajit Kumar Agarwal wrote:
> Here are the dump of the disassembly and the output of single step command for branch with delay slot and imm instructions.

Once again, please do not top post.

>>> Please provide a disassembly of the test case and a log of the commands to gdb and gdb's output, showing stepping over imm and delay slot instructions
>
> BRANCH WITH DELAY SLOT
>
> Breakpoint 1, main () at ../src/helloworld.c:28
> 28	    init_platform();
> (gdb) display /i $pc
> 1: x/i $pc
> => 0xc00001b0 <main+16>:	brlid	r15, 172	// 0xc000025c
> (gdb) si
> init_platform () at ../src/platform.c:53
> 53	{
> 1: x/i $pc
> => 0xc000025c <init_platform>:	addik	r1, r1, -32

I see the same behavior on a bare-metal MicroBlaze target without
your patch.

> The same disassembly with <main> function given above
> Without Single Stepping implementation there is a warning with the "warning: Remote failure reply: E01"  with branch with delay slot.
>
> (gdb) display /i $pc
> 1: x/i $pc
> => 0xc00001b0 <main+16>:	brlid	r15, 172	// 0xc000025c
> (gdb) si
> warning: Remote failure reply: E01
>
> [Thread <main>] #1 stopped.
> init_platform () at ../src/platform.c:53
> 53	{
> 1: x/i $pc
> => 0xc000025c <init_platform>:	addik	r1, r1, -32
>
> WITH IMM instruction : There is a same warning without the single stepping patch  "warning:Remote failure reply : E01".

I'm not able to reproduce this error on a bare-metal system
either big-endian or little-endian.  The test case which
you sent me offline does not show this error.  Single-stepping
on MicroBlaze appears to work correctly.

It appears that the "passing" test you show above was run on a
bare-metal system, while the "failing" test was run on a multi-threaded
system, presumably Linux using gdbserver.  Perhaps the error you are
seeing is in gdbserver.


-- 
Michael Eager	 eager@eagercon.com
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