[sdcc-devel] [ sdcc-Bugs-827883 ] bit literals inside cycle 'for'

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Bugs item #827883, was opened at 2003-10-22 01:42
Message generated for change (Settings changed) made by jetset
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=100599&aid=827883&group_id=599

Category: msc51(8051) target
Group: None
Status: Open
Resolution: None
>Priority: 7
Submitted By: Josef Pavlik (jetset)
Assigned to: Nobody/Anonymous (nobody)
Summary: bit literals inside cycle 'for'

Initial Comment:
hello,
Compiling the following simple program you can got buggy result. I try it with sdcc 2.3.5 (Oct 21 2003) (UNIX). You can compile it without any parameters, simply sdcc test.c

The bug is following: The bit 'e' is loaded just BEFORE cycle. (but may be never loaded)

Another thing,
The following is not an bug, but very ugly result:
The bits 'a' to 'd' are loaded from values stored in the registers before the cycle, killing a lot of registers and generating a lot of senseless code. Instead of simply setb _a etc.
-------------------------------------------------------
bit a,b,c,d,e;

main()
{
  int i;
  a=b=c=d=e=0;
  for (i=0; i<10; i++)
  {
    if (i==11)
    {
      a=1;
      b=1;
      c=1;
      d=1;
      e=1;
    }
  }
// e==1 at this point but may be 0
}
---------------------------------------------------
piece of incorrect output
---------------------------------------------------
;test.c:7: for (i=0; i<10; i++)
;     genAssign
        mov     r2,#0x01
;     genAssign
        mov     r3,#0x01
;     genAssign
        mov     r4,#0x01
;     genAssign
        mov     r5,#0x01
;     genAssign
        setb    _e
;     genAssign
        mov     r7,#0x0A
        mov     r0,#0x00
00105$:
;test.c:9: if (i==11)
;     genMinus
;     genMinusDec
        mov     a,r7
        add     a,#0xff
        mov     r1,a
        mov     a,r0
        addc    a,#0xff
        mov     r6,a
;     genCmpEq
;       Peephole 132    changed ljmp to sjmp
;       Peephole 198    optimized misc jump sequence
        cjne    r1,#0x0B,00102$
        cjne    r6,#0x00,00102$
;00111$:
;       Peephole 200    removed redundant sjmp
00112$:
;test.c:11: a=1;
;     genAssign
        mov     a,r2
        add     a,#0xff
        mov     _a,c
;test.c:12: b=1;
;     genAssign
        mov     a,r3
        add     a,#0xff
        mov     _b,c
;test.c:13: c=1;
;     genAssign
        mov     a,r4
        add     a,#0xff
        mov     _c,c
;test.c:14: d=1;
;     genAssign
        mov     a,r5
        add     a,#0xff
        mov     _d,c
;test.c:15: e=1;
;     genAssign
00102$:
;     genDjnz
;     genMinus
;     genMinusDec
        dec     r7
        cjne    r7,#0xff,00113$
        dec     r0
00113$:
;test.c:7: for (i=0; i<10; i++)
;     genIfx
        mov     a,r7
        orl     a,r0
;     genIfxJump
;       Peephole 109    removed ljmp by inverse jump logic
        jnz     00105$
00114$:
00106$:
        ret


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