[sdcc-devel] [ sdcc-Bugs-1019480 ] sign extension of signed bit-field

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Bugs item #1019480, was opened at 2004-08-31 01:35
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: sign extension of signed bit-field

Initial Comment:
In assigning signed bit-field variable to larger signed 
variable, sign extension is not processed.

Here is the code

--
struct {
  signed b : 4;
} a;

signed char c;

main()
{
  a.b = -1;
  c = a.b;
}
--

and piece of produced asm code is

--
;test.c:10: c = a.b;
;     genPointerGet
;     genNearPointerGet
	mov	r0,#_a
;     genUnpackBits
	mov	a,@r0
	anl	a,#0x0f
	mov	r2,a
;     genAssign
	mov	_c,r2
--

2nd assignment is masking lower 4bit and moving,and 
sign bit is not copied to higher 4bits.

I tested this by sdcc version `2.4.4 #816 (Aug 31 2004)'
on RedHat Linux 8.0.





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