c/4691: Incorrect warning that statement has no effect

[Donald Gillies]

Here is the full (unsimplified) code.


boolean_t OW_ReadDallasUID(u_int8_t *p)
{
    u_int8_t retry = MAX1WRETRY;    // try max times to read Dallas ID
DS2401Z
    u_int8_t CRC = 0;
    u_int8_t i;
    u_int8_t buf[8];
    intrmask_t s;

    UNIX(return(TRUE));

    s = splhigh();                    // disable all interrupts
    while ( retry ) {

        if (Reset()) {                // No devices found
            retry = 0;
            break;
        }

        OW_WriteByte(0x33);           // Send READ ROM command
        for ( i = 8; i > 0; i--) {
            buf[i-1] = OW_ReadByte();
            // After all 8 bytes CRC should be 0
            CRC = CRCTable[ (CRC ^ buf[i-1])];
        }

        // MSB( CRC ID ID ID ID ID ID  CHIP_TYPE)
        // LSB :: buf[0] = CRC, buf[7] = CHIP_TYPE

        if (CRC == 0x00) {            // if CRC OK, copy data to user
space
            for (i = 0; i < 8; i++)   // bcopy(buf, p, 8)
                *p++ = buf[i];
            break;
        }
        retry--;
    }
    splx(s);                // restore interrupts

    if (retry != 0) {
        return TRUE;
    }
    else {
        return FALSE;
    }
}




-----Original Message-----
From: neil@gcc.gnu.org [ mailto:neil@gcc.gnu.org ]
Sent: Thursday, October 25, 2001 11:42 PM
To: Donald Gillies; gcc-bugs@gcc.gnu.org; gcc-prs@gcc.gnu.org;
nobody@gcc.gnu.org
Subject: Re: c/4691: Incorrect warning that statement has no effect


Synopsis: Incorrect warning that statement has no effect

State-Changed-From-To: open->closed
State-Changed-By: neil
State-Changed-When: Thu Oct 25 23:41:45 2001
State-Changed-Why:
    Not a bug.  Please look harder at the exact line the compiler
    claims has no effect - the compiler is entirely right.  8-)

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&pr=4691&da
tabase=gcc