xref: /src/external/gpl3/gdb.old/dist/sim/ppc/BUGS

ChangeLog

See the ChangeLog file looking for lines taged with the word FIXME.


COREFILE.C:

The implementation of corefile.c (defined by corefile.h) isn't the
best.  It is intended to be functionaly correct rather than fast.  One
option being considered is to add a data cache to reduce the overhead
of the most common case of data read/writes.


VEA:

Missing VEA system calls.

powerpc.igen:

Missing or commented out instructions.


64bit:

64bit target untested. 64bit host broken.  For instance use of scanf
"%x", &long long.



hw_*.c:

Better and more devices.

PORTABILITY:

(Notes taken from Michael Meissner): Heavy use of the ## operator -
fix using the classic X/**/Y hack; Use of the signed keyword.  In
particular, signed char has no analogue in classic C (though most
implementations of classic C use signed chars); Use of long long which
restricts the target compiler to be GCC.


TRACING:

debug.c: Macro's should be extended to include:

	IS_*TRACE:	True if tracing enabled
	*TRACE_PREFIX:	Outputs just the prefix line

hw_trace.c: Flush, replace with a psim_set_tracing or some
	such program.


CIA/NIA:

Replace with functions to return/increment the CIA?



SMP & GDB:

GDB doesn't understand SMP!




OVERALL STRUCTURE:

A new file pstruct.h is to be created that contains a single flat data
structure containing:

		pstruct {
			events;
			core;
			processor[nr_cpus];
			monitor;
			devices;
			trace;
		}

The CPU's structure, in turn would contain the VM sub structures.

When SMP==0, everything would have PSTRUCT passed.  In SMP mode,
however, there are two choices: PSTRUCT + CPU_NR or PROCESSOR.  I
suspect the latter is better.

It is believed that this would significantly improve performance (at
the price of reduced control over object scope).




IGEN:

Igen at present can't do the following:

	o	duplication is an all or nothing affair.

		It should be configurable according to
		the instruction or the sub-table.


	o	Due to the naming, only a single generated
		simulator can be included in a program.

		IGEN should be able to generate multiple
		engines that can all be included in a program

	o	handle alternate architectures.


	o	Igen should support the generation of a
		disasembler and posibly an assembler.

		I suggest that the table be extended to
		include, for each instruction, additional
		lines describing the extual format of the
		instruction.

		One possible format is:

			"mtlr %RS":SPR.something
			"mtspr %SPR, %RS"