Re: [Qemu-devel] qemu-user/gdbstub : gdb remote pipe connexion addition ?

[Philippe Waille]

On Tue, Mar 24, 2009 at 12:52:57PM +0000, Paul Brook wrote:
> For userspace emulation using stdio IMHO doesn't make a whole lot of sense. 
> The user application is almost certainly already using that for something 
> else. This is different to e.g. gdbserver and openocd where the debug stub is 
> a separate process from the user application.

Ok if qemu in user mode only targets cross develop/debug/benchmark of 
complete applications in C/C++/JAVA/... for an embeded target system. But I
consider other another usage. 

An efficient user mode simulator such as qemu is also very interesting for 
(any ISA != IA32) assembly langage teaching. I  would use it to replace the 
gdb builtin ARM simulator (rdi targeti, removed from gdb since 6.4). 

Students learning assembly langage programming ususally write very 
small programs (n!, sum of array elements,...) and will only use a few basic
stdio primitives (printf/scanf/putchar/getchar) already translated in gdb 
remote file I/O by qemu gbstub. Nothing else : they don't call pipe, dup
or ioctl from assembler code !

Qemu-arm user mode with socket based gdb connexion is already a valuable tool, 
but gdb remote pipe connexion would allow cleaner and easier 
gdb starting/configuration/termination procedures (script files),
especially on shared POSIX servers.

Note : I would event be interested by ARM semihosting on gdb file I/O 
protocol through openocd and JTAG interfaces, ... but its too
much work for the benefits.

Best regards
Ph. W.

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