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Date: Mon, 07 Mar 2011 02:25:49 +0100
From: "felix.matenaar@rwth-aachen" <felix.matenaar@rwth-aachen.de>
Subject: [Qemu-devel] limitations of DEF_HELPER
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To: qemu-devel@nongnu.org

Hello *,

modifying target-i386/translate.c for calling helper functions when
specific arithmetic operations are executed.

Example:
static void gen_shift(DisasContext *s1, int op, int ot, int d, int s,
target_ulong pc_start)
{
    if (s != OR_TMP1)
        gen_op_mov_TN_reg(ot, 1, s);
    if(optrace_enabled && userspace(pc_start))
        gen_helper_opcode_event(); // custom helper function
    switch(op) {
 ...
 ...
}

What I noticed is that Qemu segfaults after some calls to these helper
functions but as far as I figured out not in my analysis code. So my
question is if there are any limitations on how helper functions can be
used because I have already hooks in disas_insn which work without any
problems.

Regards,
    Felix