Intel® High Level Synthesis Compiler Standard Edition: Reference Manual

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ID 683310
Date 12/18/2019
Public
Document Table of Contents
Document Table of Contents x
1. Intel® HLS Compiler Standard Edition Reference Manual 2. Compiler 3. C Language and Library Support 4. Component Interfaces 5. Component Memories (Memory Attributes) 6. Loops in Components 7. Component Concurrency 8. Arbitrary Precision Math Support 9. Component Target Frequency 10. Intel® High Level Synthesis Compiler Standard Edition Compiler Reference Summary A. Supported Math Functions B. Intel® HLS Compiler Standard Edition Reference Manual Archives C. Document Revision History of the Intel® HLS Compiler Standard Edition Reference Manual
2. Compiler x
2.1. Intel® HLS Compiler Standard Edition Command Options 2.2. Using Libraries in Your Component 2.3. Compiler Interoperability 2.4. Intel® HLS Compiler Pipeline Approach
3. C Language and Library Support x
3.1. Supported C and C++ Subset for Component Synthesis 3.2. C and C++ Libraries 3.3. Intel® HLS Compiler Standard Edition Compiler-Defined Preprocessor Macros
4. Component Interfaces x
4.1. Component Invocation Interface 4.2. Avalon® Streaming Interfaces 4.3. Avalon® Memory-Mapped Master Interfaces 4.4. Slave Interfaces 4.5. Component Invocation Interface Arguments 4.6. Unstable and Stable Component Arguments 4.7. Global Variables 4.8. Structs in Component Interfaces 4.9. Reset Behavior
4.1. Component Invocation Interface x
4.1.1. Scalar Parameters 4.1.2. Pointer and Reference Parameters 4.1.3. Interface Definition Example: Component with Both Scalar and Pointer Arguments
4.3. Avalon® Memory-Mapped Master Interfaces x
4.3.1. Memory-Mapped Master Testbench Constructor 4.3.2. Implicit and Explicit Examples of Describing a Memory Interface
4.4. Slave Interfaces x
4.4.1. Control and Status Register (CSR) Slave 4.4.2. Slave Memories
5. Component Memories (Memory Attributes) x
5.1. Static Variables
6. Loops in Components x
6.1. Loop Initiation Interval (ii Pragma) 6.2. Loop-Carried Dependencies (ivdep Pragma) 6.3. Loop Coalescing (loop_coalesce Pragma) 6.4. Loop Concurrency (max_concurrency Pragma) 6.5. Loop Unrolling (unroll Pragma)
7. Component Concurrency x
7.1. Serial Equivalence within a Memory Space or I/O 7.2. Concurrency Control (hls_max_concurrency Attribute)
8. Arbitrary Precision Math Support x
8.1. Declaring ac_int Data Types 8.2. Integer Promotion and ac_int Data Types 8.3. Debugging Your Use of the ac_int Data Type 8.4. Declaring ac_fixed Data Types 8.5. AC Data Types and Native Compilers
8.1. Declaring ac_int Data Types x
8.1.1. Important Usage Information on the ac_int Data Type
10. Intel® High Level Synthesis Compiler Standard Edition Compiler Reference Summary x
10.1. Intel® HLS Compiler Standard Edition i++ Command-Line Arguments 10.2. Intel® HLS Compiler Standard Edition Header Files 10.3. Intel® HLS Compiler Standard Edition Compiler-Defined Preprocessor Macros 10.4. Intel® HLS Compiler Standard Edition Keywords 10.5. Intel® HLS Compiler Standard Edition Simulation API (Testbench Only) 10.6. Intel® HLS Compiler Standard Edition Component Memory Attributes 10.7. Intel® HLS Compiler Standard Edition Loop Pragmas 10.8. Intel® HLS Compiler Standard Edition Component Attributes 10.9. Intel® HLS Compiler Standard Edition Component Default Interfaces 10.10. Intel® HLS Compiler Standard Edition Component Invocation Interface Arguments 10.11. Intel® HLS Compiler Standard Edition Component Macros 10.12. Intel® HLS Compiler Standard Edition Streaming Input Interfaces 10.13. Intel® HLS Compiler Standard Edition Streaming Output Interfaces 10.14. Intel® HLS Compiler Standard Edition Memory-Mapped Interfaces 10.15. Intel® HLS Compiler Standard Edition Arbitrary Precision Data Types
A. Supported Math Functions x
A.1. Math Functions Provided by the math.h Header File A.2. Math Functions Provided by the extendedmath.h Header File A.3. Math Functions Provided by the ac_fixed_math.h Header File
1. Intel® HLS Compiler Standard Edition Reference Manual
2. Compiler
3. C Language and Library Support
4. Component Interfaces
5. Component Memories (Memory Attributes)
6. Loops in Components
7. Component Concurrency
8. Arbitrary Precision Math Support
9. Component Target Frequency
10. Intel® High Level Synthesis Compiler Standard Edition Compiler Reference Summary
A. Supported Math Functions
B. Intel® HLS Compiler Standard Edition Reference Manual Archives
C. Document Revision History of the Intel® HLS Compiler Standard Edition Reference Manual

4.7. Global Variables

Components can use and update C++ global variables. If you access a global variable in your component function, it is implemented as an Avalon® Memory-Mapped (MM) Master interfaces, like a pointer parameter.

If you access more than one global variable, each global variable uses the same Avalon® MM Master interface, which might result in stallable arbitration. If you use pointers and non-constant global memory accesses, then the pointers and global memory accesses all share the same Avalon® MM Master interface.

In addition to the Avalon® MM Master interface, each global variable that the component uses has an input conduit that must be supplied with the address of the global variable in system memory. The input conduit arguments that are generated in the RTL are named @<global variable name> . Input conduits generated for pointer arguments omit the @ are named for the corresponding pointer argument.

If your global variable is declared as const, then no Avalon® MM Master interface and no additional input conduit is generated. Therefore, global variables declared as const use significantly less FPGA area than modifiable global variable.

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