I've started porting kaffe to our Sequent. I guess that means you'll
be hearing a lot from me in the near future. Hopefully not every one
of my questions will start a flame war.
Neither the interpreter nor the JIT (x86) run out of the box. The
interpreter looked easier to debug, so I'm tackling it first. Please
let me know if I'm just fooling myself about the JIT being difficult
to debug.
Anyway, the first problem was that HelloWorldApp wouldn't run (javac
wouldn't either, so I compiled on another machine). I turned
debugging on in machine.c and got output that looked something like
this:
Call to method java/lang/System.<clinit>()V.
000: INVOKESTATIC
ARG 0-1: 47
Call to method
java/lang/System.nullInputStream()Ljava/io/InputStream;.000:
INVOKESTATIC
ARG 0-1: 34
Call to native java/lang/System.currentTimeMillis()J.
003: LCONST_0
004: LCMP
- stack 0: long 0
- stack 2: long 0
005: IFLE
ARG 0-1: 5
- stack 0: int 0
010: NEW
ARG 0-1: 11
013: DUP
014: INVOKESPECIAL
ARG 0-1: 19
- stack 0: ref 8F460
Call to method java/lang/NullPointerException.<init>()V.
000: ALOAD_0
with things going downhill from here (eventually ending with an
assertion failure and a core dump).
Our Sequent's pretty lame, and doesn't have any way that kaffe (or I)
could figure out to get millisecond timing [1], so the currentTime
function in support.c just returned 0. Making currentTime return 1
fixes this problem, but this begs a couple questions:
- Why is nullInputStream even checking this?
- Should currentTime return (time(0) * 1000) rather than 0 on
ultra-lame systems?
- Why does this cause a null pointer exception in the first place?
Does anyone have any thoughts off the top head? In particular, is
the NullPointerException the normal case (and my system's just
handling exceptions improperly), or does it indicate some other
problem?
[1] I should say that in COFF compatibility mode there's no way to
get millisecond timing. If I didn't want to link with third-party
COFF libraries our Sequent would instantly lose it's ultra-lame
status.
Thanks in advance for your help
--
Aaron Harsh ajh at rtk.com (503)284-7581 x347
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