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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have discovered another simple false positive report from the static analyzer that seems to be clearly wrong. I think it is related to not processing bit fields correctly.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have attached the HTML report and copied the problematic function below (in case the attachment doesn’t work).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-family:Consolas'>#pragma inline(Fpga_Xbus_Busy_Wait)<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'>static void Fpga_Xbus_Busy_Wait(void)<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'>{<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'>#ifndef SOLUTION_ENGINE<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> /* Stores result of the XBUS busy request. */<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> UINT32 rsp;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'>#if DXL_DEBUG_ENABLE<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> /* Initialize the number of loops to 0. */<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> UNSIGNED fpga_samples = 0;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'>#endif<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> <o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> /* Make sure that the Xbus is idle. */<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> do {<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> rsp = PCI_Rd_Mem_Long(FPGA_PCI_MEM_ADDR+FPGA_STATUS_READ, 0);<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'>#if DXL_DEBUG_ENABLE<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> fpga_samples++;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'>#endif<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> } while(((fpga_status_t *) &rsp)->xbus_busy);<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'>#if DXL_DEBUG_ENABLE<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> /* Determine if the longest FPGA XBUS wait has been exceeded. */<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> if(FPGA_longest < fpga_samples)<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> FPGA_longest = fpga_samples;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'>#endif<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'>#endif // ifndef SOLUTION ENGINE.<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'>}<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The analyzer reports the following error:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-family:Consolas'>build\DXL\Intercom\src\init\fpga.c:119:13: warning: Branch condition evaluates to a garbage value<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> } while(((fpga_status_t *) &rsp)->xbus_busy);<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The function reads from a PCI bus and assigns the value read to the 32 bit variable rsp inside the do loop. The loop condition takes the address of rsp and casts it to a structure pointer, then dereferences the pointer to access the field xbus_busy. The definition of the structure is copied below:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-family:Consolas'>typedef struct<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'>{<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> UINT32 usb2_armed_status :1;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> UINT32 usb1_armed_status :1;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> UINT32 xbus_busy :1;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> UINT32 :1;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> UINT32 column :4;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> UINT32 :1;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> UINT32 keypad_configuration :2; <o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> UINT32 cept_configuration :2; <o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> UINT32 two_hundred_mhz_dsp :1; <o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> UINT32 hwid :2;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'> UINT32 version :16;<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:Consolas'>} fpga_status_t, fpga_configuration_t;<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The analyzer seems to miss the fact that xbus_busy is a bit field in a single 32 bit variable, rather than a separate 32 variable in a structure. The error would make sense if the structure fields were independent 32 bit variables. Then xbus_busy would be a 32 bit field at offset 8 bytes past the start of the structure. This offset clearly doesn’t exist in the single 32 bit variable rsp. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>HTH<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='mso-fareast-language:EN-CA'>--<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-CA'>Dennis Cote<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-CA'>Harding Instruments<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-CA'>780-462-7100<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>