* Tracing for floating point values
@ 2000-12-08 14:57 Ben Elliston
2000-12-14 17:04 ` Andrew Cagney
0 siblings, 1 reply; 2+ messages in thread
From: Ben Elliston @ 2000-12-08 14:57 UTC (permalink / raw)
To: CGEN; +Cc: gdb
Currently, the TRACE_RESULTS web of macros/functions in
sim/common/cgen-trace.c don't know how to handle the 'f' printf-type for SF
and DF operands. Only 'D' and 'x' are handled at present.
I set about fixing this yesterday. There were two approaches I considered:
* use the host's native printf %x. Comments in sim-fpu.[hc]
indicate this is a bad mistake. There's no guarantee that the
host will use the same floating point representation as the
target.
* use sim_fpu's sim_fpu_print_fpu to output the real number
using cgen_trace_printf as its callback (which works nicely).
However, we get very detailed output!
fr <- +1.0000,0000,0000,0000,0000,0000,0000,0000,0000,0000,0000,0000,0000,0000,0000*2^+0
Which way seems right to jump?
Ben
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Tracing for floating point values
2000-12-08 14:57 Tracing for floating point values Ben Elliston
@ 2000-12-14 17:04 ` Andrew Cagney
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Cagney @ 2000-12-14 17:04 UTC (permalink / raw)
To: Ben Elliston; +Cc: CGEN, gdb
Ben Elliston wrote:
>
> Currently, the TRACE_RESULTS web of macros/functions in
> sim/common/cgen-trace.c don't know how to handle the 'f' printf-type for SF
> and DF operands. Only 'D' and 'x' are handled at present.
>
> I set about fixing this yesterday. There were two approaches I considered:
>
> * use the host's native printf %x. Comments in sim-fpu.[hc]
> indicate this is a bad mistake. There's no guarantee that the
> host will use the same floating point representation as the
> target.
You would need to be very careful about SNaNs.
> * use sim_fpu's sim_fpu_print_fpu to output the real number
> using cgen_trace_printf as its callback (which works nicely).
> However, we get very detailed output!
>
> fr <- +1.0000,0000,0000,0000,0000,0000,0000,0000,0000,0000,0000,0000,0000,0000,0000*2^+0
>
> Which way seems right to jump?
What about a print function that outputs things in decimal - something
like ``%f'' or ``%g''. While the existing print function is really
useful for someone debugging the internals it isn't much use to normal
users.
Andrew
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2000-12-08 14:57 Tracing for floating point values Ben Elliston
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