Compiler problem again?

[lseletron]

Posted on July 31, 2007 at 10:32

Compiler problem again?

[lseletron]

Posted on July 30, 2007 at 04:38

Hi,

I followed Luca's recommendation and installed the latest Cosmic compiler. Now the .ls file says at the beginning: 1 ; C Compiler for ST7 (COSMIC Software) 2 ; Generator V4.5.5 - 12 Jan 2006 3 ; Optimizer V4.4.2 - 11 Jan 2006 But I still have problems with my program. In the following code line 1:unsigned char l_ShortAddress; line ; line 3:if(((g_DaliPacket[DALI_ADDRESS_BYTE]&0b011111110)>>1)==g_MyDaliSettings.m_ShortAddress) line 4:{ line 5:retval=DALI_NORMAL_COMMAND_FOR_ME; line 6:} line 5 will not be executed as it should. I fix the problem by uncommenting line 2, which is weird as line 2 does nothing useful. Here is the translation for both cases (line 2 commented and not commented): // Commented, not working properly: 2788 switch .text 2790 xref _IsDaliPacketForMe$L 2791 0cf5 _IsDaliPacketForMe: 2792 ; 1294 unsigned char retval=DALI_COMMAND_NOT_FOR_ME; 2793 0cf5 a601 ld a,#1 2794 0cf7 c7ffff ld _IsDaliPacketForMe$L-1,a 2795 ; 1296 if (0==GetBit(g_DaliPacket[DALI_ADDRESS_BYTE],B_7)) 2796 0cfa c6003f ld a,_g_DaliPacket 2797 0cfd 2b17 jrmi L306 2798 ; 1301 if(((g_DaliPacket[DALI_ADDRESS_BYTE]&0b011111110)>>1)==g_MyDaliSettings.m_ShortAddress) 2799 0cff 5f clr x 2800 0d00 90ce0028 ld y,_g_MyDaliSettings+4 2801 0d04 3f00 clr c_y 2802 0d06 b300 cp x,c_y 2803 0d08 2703cc0da6 jrne L706 2804 0d0d 90bf01 ld c_y+1,y 2805 0d10 b101 cp a,c_y+1 2806 0d12 26f6 jrne L706 2807 ; 1303 retval=DALI_NORMAL_COMMAND_FOR_ME; // Not commented working OK 2788 switch .text 2790 xref _IsDaliPacketForMe$L 2791 0cf5 _IsDaliPacketForMe: 2792 ; 1294 unsigned char retval=DALI_COMMAND_NOT_FOR_ME; 2793 0cf5 a601 ld a,#1 2794 0cf7 c7ffff ld _IsDaliPacketForMe$L-1,a 2795 ; 1296 if (0==GetBit(g_DaliPacket[DALI_ADDRESS_BYTE],B_7)) 2796 0cfa c6003f ld a,_g_DaliPacket 2797 0cfd 2b1b jrmi L306 2798 ; 1300 l_ShortAddress=g_MyDaliSettings.m_ShortAddress; 2799 0cff c60028 ld a,_g_MyDaliSettings+4 2800 0d02 c7fffe ld _IsDaliPacketForMe$L-2,a 2801 ; 1301 if(((g_DaliPacket[DALI_ADDRESS_BYTE]&0b011111110)>>1)==g_MyDaliSettings.m_ShortAddress) 2802 0d05 5f clr x 2803 0d06 9097 ld y,a 2804 0d08 3f00 clr c_y 2805 0d0a b300 cp x,c_y 2806 0d0c 2703cc0daa jrne L706 2807 0d11 90bf01 ld c_y+1,y 2808 0d14 b101 cp a,c_y+1 2809 0d16 26f6 jrne L706 2810 ; 1303 retval=DALI_NORMAL_COMMAND_FOR_ME; Why does this happen? I am doing something wrong? Thanks

[jpl2]

Posted on July 31, 2007 at 10:32

Hi,

There is an optimizer problem here. You should try a more efficient syntax by casting the result of the shift back to (unsigned char), as the C standard rules are considering the result of any operator as at least an int. Forcing the shift result to a char will allow a direct char compare and the optimizer will not fail with the widening: if((unsigned char)((g_DaliPacket[DALI_ADDRESS_BYTE]&0b011111110)>>1)==g_MyDaliSettings.m_ShortAddress) And the resulting code will be more efficient.