IPT-C2H-NIOS Altera, IPT-C2H-NIOS Datasheet - Page 73

• Manufacturer Part Number: IPT-C2H-NIOS
• Description: C2H COMPILER FOR NIOS II
• Manufacturer: Altera
• Series: Nios®IIr
• Type: Nios IIr

Specifications of IPT-C2H-NIOS

• Function: C to Hardware Compiler
• License: Initial License
• Software Application: IP CORE, NIOS Processor And Functions
• Core Architecture: FPGA
• Core Sub-architecture: Cyclone
• Rohs Compliant: NA
• Lead Free Status / RoHS Status: Not applicable / Not applicable

Example 3–27. Pointer Aliasing
void foo(int *ptr_a, int *ptr_b)
{
}
Altera Corporation
November 2009
int a, b;
a
*ptr_a = a + 7;
b
*ptr_b = b + 8;
= *ptr_a;
= *ptr_b;
operations that come before it. Because arrays and structures are
equivalent to pointer operations, the same considerations apply when
indexing into an array or structures.
This section describes the implications of aliasing on the C2H Compiler
and outlines methods to prevent unnecessary dependencies.
Figure 3–14
Figure 3–14. Pointer-Related Data Dependency
In this example, the C2H Compiler cannot determine whether or not
ptr_a and ptr_b ever point to the same address. Therefore, it schedules
conservatively, under the assumption that they do. The dependency
graph shows that the read operation from ptr_b depends on the write
operation to ptr_a. This is not a dependency on the variable ptr_a, but
rather a dependency on a location in memory that is unknown at
shows the dependency graph for
9.1
C-to-Hardware Mapping Reference
Nios II C2H Compiler User Guide
Example
3–27.
3–33