Hi-Tech C, Warning ?

[PICMICRO]

Compiling this test code with Hi-tech C

#include<htc.h>
void main(){
TRISC5 = 0;
unsigned char x;
x = 5;
if(x >= 0){
RC5 = 1;
}
}

issues the following warning
Warning [765] D:\pic experimental\main.c; 7. degenerate unsigned comparison

We well know what the warning means, since x is unsigned, its trivial that x >=0 is always true. But guess what? Its actually error. RC5 isn't set, the statement RC5 = 1; isn't executed at all!
My god, who would have thought like that?
It was part of my bigger program, took my whole day to figure this out.

 

[Ian Rogers]

Swap round the" trisc.5; " and the " unsigned char x; " declaration. In C all declarations MUST be placed first.

 

[PICMICRO]

Hi, Ian
Thats allowed in Hi-Tech C.
Swaping as you said, won't help.

 

[Ian Rogers]

I have never tried to declare var's like that ... However, doesn't it pi** you off when software glitches like this come along...Keeps the brain going...

 

[Pommie]

Irrelevant post removed.

Mike.

 

[Pommie]

Irrelevant post removed.

Mike.

 

[Pommie]

The asm is correct and the simulator executes it correctly.

1:                 
2:                 #include<htc.h>
3:                 void main(){
4:                 unsigned char x;
5:                     x = 5;
  0003    3005     MOVLW 0x5
  0004    00F0     MOVWF 0x70
6:                 TRISC5 = 0;
  0005    1683     BSF 0x3, 0x5
  0006    1303     BCF 0x3, 0x6
  0007    1287     BCF 0x7, 0x5
7:                     if(x >= 0){
8:                         RC5 = 1;
  0008    1283     BCF 0x3, 0x5
  0009    1303     BCF 0x3, 0x6
  000A    1687     BSF 0x7, 0x5
9:                     }
10:                }
  000B    120A     BCF 0xa, 0x4

Maybe you need to add a while(1) instead of getting to the end of main().

Mike.

 

[PICMICRO]

The asm is correct and the simulator executes it correctly.

1:                 
2:                 #include<htc.h>
3:                 void main(){
4:                 unsigned char x;
5:                     x = 5;
  0003    3005     MOVLW 0x5
  0004    00F0     MOVWF 0x70
6:                 TRISC5 = 0;
  0005    1683     BSF 0x3, 0x5
  0006    1303     BCF 0x3, 0x6
  0007    1287     BCF 0x7, 0x5
7:                     if(x >= 0){
8:                         RC5 = 1;
  0008    1283     BCF 0x3, 0x5
  0009    1303     BCF 0x3, 0x6
  000A    1687     BSF 0x7, 0x5
9:                     }
10:                }
  000B    120A     BCF 0xa, 0x4

Maybe you need to add a while(1) instead of getting to the end of main().

Mike.

Hi, Pommie,
Which version of compiler did you use?
Also, how do I create the assmebly listing like that. I tried View->Disassmebly Listing from Mplab and got this.

---  D:\pic experimental\exp.as  -----------------------------------------------------------------
1:                 opt subtitle "HI-TECH Software Omniscient Code Generator (PRO mode) build 5239"
2:                 
3:                 opt pagewidth 120
4:                 
5:                 	opt pm
6:                 
7:                 	processor	16F877A
8:                 clrc	macro
9:                 	bcf	3,0
10:                	endm
11:                clrz	macro
12:                	bcf	3,2
13:                	endm
14:                setc	macro
15:                	bsf	3,0
16:                	endm
17:                setz	macro
18:                	bsf	3,2

........
<REMOVED BECAUSE ITS TOO LONG>
...............................................

608:               psect cinit,class=CODE,delta=2
609:               global end_of_initialization
610:               
611:               ;End of C runtime variable initationation code
612:               
613:               end_of_initialization:
614:               clrf status
  07F5    0183     CLRF 0x3
615:               ljmp _main	;jump to C main() function
  07F6    120A     BCF 0xa, 0x4
  07F7    118A     BCF 0xa, 0x3
  07F8    2FF9     GOTO 0x7f9
---  D:\pic experimental\main.c  -----------------------------------------------------------------
1:                 #include<htc.h>
2:                 
3:                 void main(){
4:                 unsigned char x;
5:                 x = 5;
6:                 TRISC5 = 0;
  07F9    1683     BSF 0x3, 0x5
  07FA    1287     BCF 0x7, 0x5
7:                 if(x >= 1){
8:                 RC5 = 1;
  07FB    1283     BCF 0x3, 0x5

 

[Pommie]

I'm using HI-TECH C PRO for the PIC10/12/16 MCU family (Lite) V9.65PL1 with MPLAB v8.40 and just did View->Disassembly.

Mike.

 

[PICMICRO]

I am using HI-TECH C Compiler for PIC10/12/16 MCUs (PRO Mode) V9.70
with mplab 8.66
Seems like issue with my Version