[sdcc-devel] [ sdcc-Bugs-1230095 ] Constants error

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Bugs item #1230095, was opened at 2005-06-29 21:30
Message generated for change (Comment added) made by jimatjtan
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Category: msc51(8051) target
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Daniel_Sanchez (daniel_sanchez)
Assigned to: Nobody/Anonymous (nobody)
Summary: Constants error

Initial Comment:
Sample code:

Whith:
#define EISA 20
#define PSWSIZE 6
#define RCDSIZE PSWSIZE+2  // In this case is 8

Doing:

  for (addr = EISA; addr < (EE_SIZE - RCDSIZE); 
addr++)

The ASM code generated is:

;------------------------------------------------------------
;Allocation info for local variables in function 'FindFirst'
;------------------------------------------------------------
;addr                      Allocated to registers r3 r4
;------------------------------------------------------------
;uaccess.c:1171: for (addr = EISA; addr < (EE_SIZE - 
RCDSIZE); addr++)
;     genAssign
	mov	r3,#0x14
	mov	r4,#0x00
00104$:
;     genCmpLt
;     genCmp
	clr	c
	mov	a,r3
	subb	a,#0xFC
	mov	a,r4
	subb	a,#0x01
;     genIfxJump
;	Peephole 108	removed ljmp by 
inverse jump logic
	jnc	00107$

Note that 01FC is not equal to EE_SIZE - RCDSIZE.
But if in place of RCDSIZE I write 8, then the compiler 
shows the right value, 01F8.

Is this a bug ?

Thank you.

Best regards

Daniel Sanchez

Informations required:
- Exact command used to run SDCC on this sample 
code:

sdcc --opt-code-size --verbose --out-fmt-ihx %f 
uaccess.c

- SDCC version tested:
2.4.6 #879 (Nov 12 2004)(MINGW32)

- My e-mail:
das...@uo...


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

Comment By: Jim Paris (jimatjtan)
Date: 2005-06-30 00:35

Message:
Logged In: YES 
user_id=175928

No, your C code is incorrect.  #define creates a
preprocessor macro that turns into a literal substitution,
not a constant.  In this case, (EE_SIZE - RCDSIZE) turns
into (EE_SIZE - PSWSIZE + 2) which is very different from
(EE_SIZE - (PSWSIZE + 2)).  Put parens around the definition
of RCDSIZE!

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

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=100599&aid=1230095&group_id=599