On Sunday 17 February 2008 00:45, Martinb_ARM_NOMMU_KISSDVD wrote:
> The lineedit.s is attach
>
> and if i do the:
>
> > - if (num <= 4) {
> > + if (0) {
>
> its running 100% like it should (also the home and end key)
> Thanks for fixing this last part , i now can use hush and remove the old
> lash from rom
so printf(("\b\b\b\b" + 4) - num) is compiled into:
.LC0:
.ascii "\b\b\b\b\000"
.align 2
...
#APP
# HERE
ldr r0, .L27+8 @ tmp90,
rsb r0, r4, r0 @, num, tmp90
ldmfd sp!, {r4, r5, lr} @
b printf @
...
.L27:
.word ptr_to_statics
.word .LC1
.word .LC0+4 <====== third word
.word .LC2
Let's see:
ldr r0, .L27+8
loads third 32 bit word from .L27. This word seems to correctly
point to four bytes past the beginning of "\b\b\b\b" string.
But since we see garbage instead of correct output,
I guess the value in this word (.word .LC0+4) gets trashed
by the time we reach "ldr r0, .L27+8"! We get a pointer to garbage,
and we output garbage.
I looked at the file and I cannot see where that happens,
but it definitely happens. This is not good.
I am not happy. Just removing if() doesn't fix the problem
of something corrupting memory.
Just in case I read the code incorrectly (it seems to be ok,
but maybe I can't read ARM?), let's try to fool gcc into
producing a bit different code?
can you try re-phrasing the code as follows:
if (cmdedit_x >= num) {
const char *bbbb = "\b\b\b\b";
cmdedit_x -= num;
if (num <= 4) {
bbbb -= num;
asm volatile("# HERE");
printf(bbbb);
return;
}
printf("\033[%uD", num);
return;
}
run test it and also send me the result of "make libbb/lineedit.s"
again.
> I will do some more extensive testing and wil give a shout to the list if i
> find something else
>
>
> just for my information i was looking in
> http://www.busybox.net/cgi-bin/viewcvs.cgi/branches/busybox_1_8_stable/libbb
> /lineedit.c?rev=20160&view=markup
Doesn't work here too.
Try
http://busybox.net/cgi-bin/viewcvs.cgi/trunk/busybox/libbb/lineedit.c?rev=21021&view=markup
> to find when this code was edit (and why) but the cvs is not giving me te
> results
> is it broken?
>
> one more question for the list:
> is the job control option of any use for a NOMMU system? (i understand its
> use, but im not sure if its of any use for nommu)
Job control is useful on NOMMU. It is just harder to
implement there.
Well, on NOMMU running "command &" is easy to implement,
but, for example, making "{ command; command2; } &"
work correctly would be much more difficult.
--
vda
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