[sdcc-devel] [ sdcc-Bugs-704878 ] Missing (or bad) peephole fix

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Bugs item #704878, was opened at 2003-03-17 10:14
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=100599&aid=704878&group_id=599

Category: ds390 target
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Jan Rejlek (jare)
Assigned to: Bernhard Held (bernhardheld)
Summary: Missing (or bad) peephole fix

Initial Comment:
In the ds390/peeph.def there are two unlabelled
peephole rules at position #213. The first of them
should be changed (or added?) to something like this:

replace {
	mov  %1,#(( %2 >> 16 ) ^ 0x80)
} by {	
        ;       Peephole 213.a  inserted fix
	mov  %1,#(%2 >> 16)
	xrl  %1,#0x80
} if portIsDS390

The same problem is probably also with the second
unlabelled rule.

Without this fix the pointer comparison is impossible
to compile.

Regards,
Jan Rejlek


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>Comment By: Jan Rejlek (jare)
Date: 2003-03-17 11:12

Message:
Logged In: YES 
user_id=672939

ok, here is the source:

xdata char a[2000];
unsigned n;

int main()
{
	xdata char *ptr = a + n;

	if (ptr < a + sizeof a) {
		*ptr = 0;
	}
}

... and here is the problem (line 203)
                            187 ;	test.c:8: if (ptr < a +
sizeof a) {
                            188 ;	genAssign 
                            189 ;	genAssign: resultIsFar = FALSE
   0054 AD 84               190 	mov	r5,dpl1
   0056 AE 85               191 	mov	r6,dph1
   0058 AF 95               192 	mov	r7,dpx1
                            193 ;	genCmpLt 
                            194 ;	genCmp
   005A C3                  195 	clr	c
   005B ED                  196 	mov	a,r5
   005C 94rD0               197 	subb	a,#(_a + 0x07d0)
   005E EE                  198 	mov	a,r6
   005F 94s07               199 	subb	a,#((_a + 0x07d0) >> 8)
   0061 EF                  200 	mov	a,r7
   0062 64 80               201 	xrl	a,#0x80
                            202 ; Peephole 159   avoided xrl
during execution
r  0064 75 F0 50            203 	mov  b,#(((_a + 0x07d0) >>
16) ^ 0x80)
   0067 95 F0               204 	subb	a,b
                            205 ;	genIfxJump
                            206 ; Peephole 108   removed
ljmp by inverse jump logic
   0069 50 07               207 	jnc  00103$
   006B                     208 00106$:

Jan Rejlek

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

Comment By: Bernhard Held (bernhardheld)
Date: 2003-03-17 10:45

Message:
Logged In: YES 
user_id=203539

Could you please post a piece of source, which shows the 
problem?

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

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