topic Re: Switch statement problems with Codewarrior 5.0 in CodeWarrior for MCU

Switch statement problems with Codewarrior 5.0

FC — Mon, 24 Aug 2009 04:33:37 GMT

Hello,

For switch statments with a lot of labels, the simulator does not select the correct label. It produces a lot of exta instructions. If a few labels are used, then it works fine. Below is the sample code. For example, if level = 4, the simulator selects 12.

Thansks

switch(DISPLevelCode)
{

    case 1:     DISPGraphData = 0x03;
                   break;
    case 2:     DISPGraphData = 0x0F;
                   break;
    case 3:     DISPGraphData = 0x3F;
                   break;
    case 4:     DISPGraphData = 0xFF;
                   break;
    case 8:     DISPGraphData = 0x01;
                   break;
    case 9:     DISPGraphData = 0x07;
                   break;
    case 10:   DISPGraphData = 0x1F;
                   break;
    case 11:   DISPGraphData = 0x7F;
                   break;
    case 12:   DISPGraphData = 0xFF;
                  break;
    default:    DISPGraphData = 0x00;

Re: Switch statement problems with Codewarrior 5.0

bigmac — Mon, 24 Aug 2009 08:27:00 GMT

Hello,

I wonder if this is an issue of optimisation by the compiler, since the same action occurs for case 4 and case 12. You could have equally written this code in the following form, and there would be no issue.

case 4:

case 12:

DISPGraphData = 0xFF; break;

Does the issue still occur if different values are assigned in each of the cases?

Regards,

Mac

Re: Switch statement problems with Codewarrior 5.0

CompilerGuru — Mon, 24 Aug 2009 09:17:05 GMT

It's probably the branch tail merging optimization which combines the identical case entries.

Try with "-onb=t -onbt".

Daniel

BTW: Please always list which cpu you are targeting.