You are here: NI Home > Support > Product Reference > Manuals > LabVIEW Microprocessor SDK 2.5 Help

The C parser searches the generated C code for special comments and maps the comments to line numbers. When a user selects On Chip debugging in the Build Specification Properties dialog box, the LabVIEW C Code Generator adds a set of comments to the generated C code to notate where potential probes, breakpoints, controls, and indicators might be placed. For example, the extra comments generated for simple_math.vi is as follows:

hA8EA7A0->sCA8/* n: MultiplyConstant */ = 5.0000000000000000000E+2;

hA8EA7A0->sA9C/* n: DivideConstant */ = 1.0000000000000000000E+2;

hA8EA7A0->sBEC/* n: NumberIn */ =NumberIn__1364;

OCDI_BEGIN_NODE(profileInfo_simple_math, 0, 2) /* OCDI::Begin::Node(1, 2, 3) */

/**/

/* Multiply */

/**/

OCDI_CHECK_POINT(simple_math_OCDIFlag[0] & 0x1, &simple_math_OCDIFlag, 0)/* OCDI::BreakPoint::Node(1, 2, 3) */

hA8EA7A0->sB58/* n: Multiply: x*y */ = hA8EA7A0->sBEC/* n: NumberIn */ * hA8EA7A0->sCA8/* n: MultiplyConstant */;

OCDI_END_NODE(profileInfo_simple_math, 0, 2) /* OCDI::End::Node(1, 2, 3) */

OCDI_BEGIN_NODE(profileInfo_simple_math, 1, 3) /* OCDI::Begin::Node(2, 3, 3) */

/**/

/* Divide */

/**/

OCDI_CHECK_POINT(simple_math_OCDIFlag[0] & 0x2, &simple_math_OCDIFlag, 1)/* OCDI::BreakPoint::Node(2, 3, 3) */ hA8EA7A0->sA08/* n: Divide: x/y */ = (float64)hA8EA7A0->sB58/* n: Multiply: x*y *//(float64)hA8EA7A0->sA9C/* n:DivideConstant */;

OCDI_END_NODE(profileInfo_simple_math, 1, 3) /* OCDI::End::Node(2, 3, 3) */

if (NumberOut__616) {

*NumberOut__616 =hA8EA7A0->sA08/* n: Divide: x/y */;

}

return eFinished;

This information is stored in the debug database, which translates control and signal IDs into relative symbol addresses. The database records for all breakpoints only map breakpoint IDs into line numbers. For controls and indicators, the C parser does not store actual offsets because the parser does not know the layout of the ControlDataItem structure. Instead, the parser stores indexes to the ControlDataItem table. To convert the index value to the actual offset, you must multiply the index value with the size of the ControlData structure and add the offset of the hValue variable of the ControlDataItem structure.

The list parser must resolve relative offsets of all breakpoints. You do not need to port the C parser because the parser is target independent. The C parser generates the bold portion of the following LVM file for simple_math.vi:

[simple_math.vi]

Node(1,2,3)@92=0x4011BF

Node(2,3,3)@99=0x40122B

Location.Node(1,2,3)@[88..94]

Location.Node(2,3,3)@[95..101]

SID_2716=0x4727A0

SID_2904=0x4727A8

SID_3052=0x4727B0

SID_3240=0x4727B8

SID_2568=0x4727C0

For nodes, the syntax for this portion of the LVM file is as follows:

Node(a, b, c)@x=...

where ( a , b , c ) represents the unique LabVIEW-generated coordinates that identify the node on the block diagram, and x represents the line number where the comment occurs.

For node location information, the syntax for this portion of the LVM file is as follows:

Location.Node(1,2,3)@[123...456]

Location.SNode(1,2,3)@[123...456]

Location.SRN(1,2,3)@[123...456]

where Location.Node represents nodes, Location.SNode represents structures, and Location.SRN represents self-referencing nodes. [123...456] represents the line numbers in the generated C file.

For controls and signals, the syntax for this portion of the LVM file is as follows:

CID_i=...

SID_i=...

where CID represents Control ID, SID represents Signal ID, and i represents the unique LabVIEW-generated object ID.