[sdcc-devel] [ sdcc-Bugs-851607 ] Tricky code crashes compiler

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Bugs item #851607, was opened at 2003-11-30 17:38
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Herbert Oppmann (mtx500)
Assigned to: Nobody/Anonymous (nobody)
Summary: Tricky code crashes compiler

Initial Comment:
Platform: Win32 (Windows 98SE)
SDCC :
mcs51/gbz80/z80/avr/ds390/pic16/pic14/TININative/xa51/ds400/hc08
2.3.6 (Nov 30 2003) (MSVC)
This is the 2003-11-28 snapshot compiled with Microsoft
Visual Studio 6.0, Service Pack 5

This tricky piece of code:

void main(void)
{
    int a;
    a = ((int * ()) "\x00\xc9")();	/* Z80 NOP, RET */
}

Compiled with:

sdcc.exe -S -mz80 test1.c

Results in:

test1.c:4: error: called object is not a function
Caught signal 11: SIGSEGV

The error message is ok, but the access violation (NULL
pointer) is not.

This tricky piece of code is sometimes used to directly
insert and call opcodes (machine language) with
compilers that don't support inline assembly or the
emit() builtin function.
I've read about this in comp.lang.asm.x86 and tried it
out with several compilers.
It may relief the developers of SDCC to know that
Borland C++ 5.02 also crashes on this one :-)


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