[sdcc-devel] [ sdcc-Bugs-2719592 ] problem with bit variable

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Bugs item #2719592, was opened at 2009-03-28 21:37
Message generated for change (Comment added) made by maartenbrock
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Category: mcs51(8051) target
>Group: fixed
>Status: Closed
>Resolution: Fixed
Priority: 5
Private: No
Submitted By: Zsolt Kalmar (bende99)
>Assigned to: Maarten Brock (maartenbrock)
Summary: problem with bit variable

Initial Comment:
I use the followin g routine as a BCD to ASCII converter:

/*-----------------------------------------------------------------*/
 xdata unsigned char * BCD_2_ASCII(xdata unsigned char *input,
			         unsigned char number_of_chars, xdata unsigned char *output)
 {

  data unsigned char i, j, ascii;
  bit leading_zero;

  leading_zero=1;
  j=0;
  for (i=number_of_chars; i>0; i--)
						  {
							ascii=(*(input+i-1)>>4)+'0';
							leading_zero&=(ascii=='0');
							if (!leading_zero)
													{
													 *(output+j)=ascii;
													 j++;
													}
							ascii=(*(input+i-1)&0x0f)+'0';
							leading_zero&=(ascii=='0');
							if (!leading_zero)
													{
													 *(output+j)=ascii;
													 j++;
													}



						  }
 if (leading_zero)
						{
						 *output='0';
						 j++;
						}

 *(output+j)=0x0d;
 return input+number_of_chars;

}

/*-----------------------------------------------------------------*/

I use SDCC version 2.9.0:

SDCC : mcs51/gbz80/z80/avr/ds390/pic16/pic14/TININative/xa51/ds400/hc08 2.9.0 #5416 (Mar 22 2009) (MINGW32)


I've got the following error report: Caught error 11: SIGSEGV
sdcpp.exe: fatal error: when writing output to : m

If I declare leading zero as a char, everything is OK.

If I use SDCC version 2.7.0 or 2.6.0 , I don't get error message.



----------------------------------------------------------------------

>Comment By: Maarten Brock (maartenbrock)
Date: 2009-09-06 14:11

Message:
Applied the patch in SDCC 2.9.2 #5512.
Thank you.

----------------------------------------------------------------------

Comment By: Robert Larice (rlar)
Date: 2009-03-30 19:56

Message:
I propose the following regression test for this problem.
I've also included a small change for mcs51/gen.c
   which demonstrates a cure to the issue. But I've 
   to admit, I don't grasp enough of semantics and
   interaction of the IS_OP_ACCUSE AOP_CRY etc macros,
   and  can't recommend to apply this just as it is.

Index: src/mcs51/gen.c
===================================================================
--- src/mcs51/gen.c	(revision 5420)
+++ src/mcs51/gen.c	(working copy)
@@ -6734,6 +6734,11 @@
                 {
                   emitcode ("anl", "c,%s", AOP (right)->aopu.aop_dir);
                 }
+              else if (IS_OP_ACCUSE (right))
+                {
+                  emitcode ("rrc", "a");
+                  emitcode ("anl", "c,%s", AOP (left)->aopu.aop_dir);
+                }
               else
                 {
                   emitcode ("mov", "c,%s", AOP (right)->aopu.aop_dir);
Index: support/regression/tests/my-2719592.c
===================================================================
--- support/regression/tests/my-2719592.c	(revision 0)
+++ support/regression/tests/my-2719592.c	(revision 0)
@@ -0,0 +1,27 @@
+/*
+ * my-2719592.c
+ *   (compile "make -C .. ALL_TESTS='./tests/my-2719592.c'")
+ */
+
+#include <testfwk.h>
+#include <stdint.h>
+
+#if !defined(SDCC_ds390) && !defined(SDCC_mcs51)
+#define bit char
+#endif
+
+bit foo(char i, bit bv)
+{
+  bv &= (i == 1);
+  return bv;
+}
+
+void
+testBug(void)
+{
+  ASSERT( !foo(0,0) );
+  ASSERT( !foo(0,1) );
+  ASSERT( !foo(1,0) );
+  ASSERT(  foo(1,1) );
+}
+



----------------------------------------------------------------------

Comment By: Robert Larice (rlar)
Date: 2009-03-28 23:23

Message:
the problem boils down to 
  mcs51/gen.c aprox line 6739, function genAnd
  with IS_OP_ACCUSE(left) == false
  but  IS_OP_ACCUSE(right) == true
the second one being most unexpected here.
at the beginning of the function, there are several swaps
  of left and right operand ...


----------------------------------------------------------------------

Comment By: Robert Larice (rlar)
Date: 2009-03-28 22:36

Message:
for debugging purpose, the offending code can be reduced to

void foo() {
  bit  bv = 1;
  char i;

  for (i=2; i>0; i--)
    bv &= (i == 1);
}

and compiled with
   sdcc -mmcs51 -c this.c

----------------------------------------------------------------------

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