Intel® High Level Synthesis Compiler Pro Edition: Reference Manual

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Date 3/28/2022
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Document Table of Contents
Document Table of Contents x
1. Intel® HLS Compiler Pro 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. Systems of Tasks 11. Libraries 12. Advanced Hardware Synthesis Controls 13. Intel® High Level Synthesis Compiler Pro Edition Reference Summary A. Advanced Math Source Code Libraries B. Supported Math Functions C. Cyclone® V Restrictions D. Intel® HLS Compiler Pro Edition Reference Manual Archives E. Document Revision History of the Intel® HLS Compiler Pro Edition Reference Manual
2. Compiler x
2.1. Intel® HLS Compiler Pro Edition Command Options 2.2. Using Libraries in Your Component 2.3. Compiler Interoperability 2.4. Intel® HLS Compiler Hardware Model
2.3. Compiler Interoperability x
2.3.1. Compiling Your Testbench and Component Separately
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. Templated and Overloaded Functions 3.4. Intel® HLS Compiler Pro Edition Compiler-Defined Preprocessor Macros
3.3. Templated and Overloaded Functions x
3.3.1. Templated Functions 3.3.2. Overloaded Functions 3.3.3. Function Name Mapping
4. Component Interfaces x
4.1. Component Invocation Interface 4.2. Avalon® Streaming Interfaces 4.3. Pipes 4.4. Avalon® Memory-Mapped Host Interfaces 4.5. Agent Interfaces 4.6. Stable Component Parameters 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 Invocation Interface Control Attributes 4.1.4. Interface Definition Example: Component with Both Scalar and Pointer Arguments
4.3. Pipes x
4.3.1. The pipe Class and Its Use
4.4. Avalon® Memory-Mapped Host Interfaces x
4.4.1. Memory-Mapped Host Testbench Constructor 4.4.2. Implicit and Explicit Examples of Describing a Memory Interface 4.4.3. Avalon® Memory-Mapped Host Interfaces and Load-Store Units
4.4.3. Avalon® Memory-Mapped Host Interfaces and Load-Store Units x
4.4.3.1. Load-Store Unit Types 4.4.3.2. Memory-Access Coalescing and Load-Store Units
4.5. Agent Interfaces x
4.5.1. Control and Status Register (CSR) Agent 4.5.2. Agent 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 Unrolling (unroll Pragma) 6.5. Loop Concurrency (max_concurrency Pragma) 6.6. Loop Iteration Speculation (speculated_iterations Pragma) 6.7. Loop Pipelining Control (disable_loop_pipelining Pragma) 6.8. Loop Interleaving Control (max_interleaving Pragma) 6.9. Loop Fusion
6.9. Loop Fusion x
6.9.1. Loop Fusion Control (loop_fuse Pragma) 6.9.2. Loop Fusion Exemption (nofusion pragma)
7. Component Concurrency x
7.1. Serial Equivalence within a Memory Space or I/O 7.2. Concurrency Control (hls_max_concurrency Attribute) 7.3. Component Pipelining Control (hls_disable_component_pipelining Attribute)
8. Arbitrary Precision Math Support x
8.1. Declaring ac_int Data Types 8.2. Declaring ac_fixed Data Types 8.3. Declaring ac_complex Data Types 8.4. AC Data Types and Native Compilers 8.5. Declaring hls_float Data Types
8.1. Declaring ac_int Data Types x
8.1.1. Important Usage Information on the ac_int Data Type 8.1.2. Integer Promotion and ac_int Data Types 8.1.3. Debugging Your Use of the ac_int Data Type
8.2. Declaring ac_fixed Data Types x
8.2.1. Arbitrary Precision Fixed-Point Literals in Operations
8.5. Declaring hls_float Data Types x
8.5.1. Operators and Return Types Supported by the hls_float Data Type 8.5.2. Additional Data Types Provided By hls_float.h
9. Component Target Frequency x
9.1. Effects of Specifying Target II and Target fMAX
10. Systems of Tasks x
10.1. Task Functions 10.2. Internal Streams 10.3. System of Tasks Simulation
11. Libraries x
11.1. Static-Object Libraries 11.2. Creating a Static-Object Library 11.3. Creating Objects From HLS Code 11.4. Creating Objects From RTL Code 11.5. Packaging Object Files Into a Library
11.3. Creating Objects From HLS Code x
11.3.1. Creating an Object File From HLS Code 11.3.2. Supported OpenCL* Language Constructs
11.4. Creating Objects From RTL Code x
11.4.1. RTL Modules and the HLS Pipeline 11.4.2. Creating a Static-Object File from an RTL Module
11.4.1. RTL Modules and the HLS Pipeline x
11.4.1.1. Integration of an RTL Module into the HLS Pipeline 11.4.1.2. RTL Module Interfaces 11.4.1.3. RTL Reset and Clock Signals 11.4.1.4. Object Manifest File Syntax 11.4.1.5. Mapping HLS Data Types to RTL Signals 11.4.1.6. HLS Emulation Models for RTL-Based Functions 11.4.1.7. Potential Incompatibility between RTL Modules and Partial Reconfiguration 11.4.1.8. Stall-Free RTL 11.4.1.9. RTL Module Restrictions and Limitations for HLS Libraries
11.4.1.2. RTL Module Interfaces x
11.4.1.2.1. RTL Module Interface Signals
11.4.1.3. RTL Reset and Clock Signals x
11.4.1.3.1. Intel® Agilex™ and Intel® Stratix® 10 Design-Specific Reset Requirements for Stall-Free and Stallable RTL Modules
11.4.1.4. Object Manifest File Syntax x
11.4.1.4.1. XML Elements for ATTRIBUTES 11.4.1.4.2. XML Elements for INTERFACE 11.4.1.4.3. XML Elements for RESOURCES
11.4.1.4.1. XML Elements for ATTRIBUTES x
11.4.1.4.1.1. Interaction Between ALLOW_MERGINGand HAS_SIDE_EFFECTS Elements
12. Advanced Hardware Synthesis Controls x
12.1. Hardware Implementation Control for Math Functions 12.2. The hls_fpga_reg() Function
12.1. Hardware Implementation Control for Math Functions x
12.1.1. Math Function Hardware Implementation Summary 12.1.2. The --dsp-mode Command Option 12.1.3. The ihc::math_dsp_control Function
13. Intel® High Level Synthesis Compiler Pro Edition Reference Summary x
13.1. Intel® HLS Compiler Pro Edition i++ Command-Line Arguments 13.2. Intel® HLS Compiler Pro Edition Header Files 13.3. Intel® HLS Compiler Pro Edition Compiler-Defined Preprocessor Macros 13.4. Intel® HLS Compiler Pro Edition Keywords 13.5. Intel® HLS Compiler Pro Edition Simulation API (Testbench Only) 13.6. Intel® HLS Compiler Pro Edition Component Memory Attributes 13.7. Intel® HLS Compiler Pro Edition Loop Pragmas 13.8. Intel® HLS Compiler Pro Edition Scope Pragmas 13.9. Intel® HLS Compiler Pro Edition Component Attributes 13.10. Intel® HLS Compiler Pro Edition Component Default Interfaces 13.11. Intel® HLS Compiler Pro Edition Component Invocation Interface Control Attributes 13.12. Intel® HLS Compiler Pro Edition Component Macros 13.13. Intel® HLS Compiler Pro Edition Systems of Tasks API 13.14. Intel® HLS Compiler Pro Edition Pipes API 13.15. Intel® HLS Compiler Pro Edition Streaming Input Interfaces 13.16. Intel® HLS Compiler Pro Edition Streaming Output Interfaces 13.17. Intel® HLS Compiler Pro Edition Memory-Mapped Interfaces 13.18. Intel® HLS Compiler Pro Edition Load-Store Unit Control 13.19. Intel® HLS Compiler Pro Edition Arbitrary Precision Data Types
13.13. Intel® HLS Compiler Pro Edition Systems of Tasks API x
13.13.1. ihc::stream Class
A. Advanced Math Source Code Libraries x
A.1. Random Number Generator Library A.2. Matrix Multiplication Library A.3. Cholesky Decomposition Library
B. Supported Math Functions x
B.1. Math Functions Provided by the math.h Header File B.2. Math Functions Provided by the extendedmath.h Header File B.3. Math Functions Provided by the ac_fixed_math.h Header File B.4. Math Functions Provided by the hls_float.h Header File B.5. Math Functions Provided by the hls_float_math.h Header File B.6. Default Rounding Schemes and Subnormal Number Support
1. Intel® HLS Compiler Pro 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. Systems of Tasks
11. Libraries
12. Advanced Hardware Synthesis Controls
13. Intel® High Level Synthesis Compiler Pro Edition Reference Summary
A. Advanced Math Source Code Libraries
B. Supported Math Functions
C. Cyclone® V Restrictions
D. Intel® HLS Compiler Pro Edition Reference Manual Archives
E. Document Revision History of the Intel® HLS Compiler Pro Edition Reference Manual

13.2. Intel® HLS Compiler Pro Edition Header Files

Coding your component to be compiled by the Intel® HLS Compiler requires you to include the hls.h header file. Other header files provided with the Intel® HLS Compiler provide FPGA-optimized implementations of certain C and C++ functions.

Table 37.   Intel® HLS Compiler Pro Edition Header Files Summary
HLS Header File Description
HLS/hls.h Required for component identification and component parameter interfaces.
HLS/math.h Includes FPGA-specific definitions for the math functions from the math.h for your operating system.
HLS/extendedmath.h Includes additional FPGA-specific definitions of math functions not in math.h.
HLS/ac_int.h Provides FPGA-optimized arbitrary width integer support.
HLS/ac_fixed.h

Provides FPGA-optimized arbitrary precision fixed point support.

HLS/ac_fixed_math.h

Provides FPGA-optimized arbitrary precision fixed point math functions.

HLS/ac_complex.h Provides FPGA-optimized complex number support.
HLS/hls_float.h Provides FPGA-optimized arbitrary-precision IEEE-754 compliant floating-point number support.
HLS/hls_float_math.h Provides FPGA-optimized floating-point math functions.
HLS/math_dsp_control.h Provides the ihc::math_dsp_control function to control the hardware implementation for supported data types and math functions at a local-scope.
HLS/stdio.h Provides printf support for components so that printf statements work in x86 emulations, but are disabled in component when compiling to an FPGA architecture.
<iostream> To use cout and cerr in your component, guard the statements with the HLS_SYNTHESIS macro.

hls.h Header File

Syntax
#include "HLS/hls.h"
Description
Required for component identification and component parameter interfaces.

math.h Header File

Syntax
#include "HLS/math.h"
Description
Includes FPGA-specific definitions for the math functions from the math.h for your operating system.

To learn more, review the following tutorial: <quartus_installdir>/hls/examples/tutorials/best_practices/single_vs_double_precision_math.

extendedmath.h Header File

Syntax
#include "HLS/extendedmath.h"
Description
Includes additional FPGA-specific definitions of math functions not in math.h.

To learn more, review the following design: <quartus_installdir>/hls/examples/QRD.

ac_int.h Header File

Syntax
#include "HLS/ac_int.h"
Description
Intel® HLS Compiler version of ac_int header file.

Provides FPGA-optimized arbitrary width integer support.

To learn more, review the following tutorials:
  • <quartus_installdir>/hls/examples/tutorials/ac_datatypes/ac_int_basic_ops
  • <quartus_installdir>/hls/examples/tutorials/ac_datatypes/ac_int_overflow
  • <quartus_installdir>/hls/examples/tutorials/best_practices/struct_interfaces

ac_fixed.h Header File

Syntax
#include "HLS/ac_fixed.h"
Description
Intel® HLS Compiler version of the ac_fixed header file.

Provides FPGA-optimized arbitrary precision fixed point support.

To learn more, review the following tutorial: <quartus_installdir>/hls/examples/tutorials/ac_datatypes/ac_fixed_constructor.

ac_fixed_math.h Header File

Syntax
#include "HLS/ac_fixed_math.h"
Description
Intel® HLS Compiler version of the ac_fixed_math header file.

Provides FPGA-optimized arbitrary precision fixed point math functions.

To learn more, review the following tutorial: <quartus_installdir>/hls/examples/tutorials/ac_datatypes/ac_fixed_math_library.

ac_complex.h Header File

Syntax
#include "HLS/ac_complex.h"
Description
Intel® HLS Compiler version of the ac_comple header file.

Provides FPGA-optimized complex math functions.

hls_float.h Header File

Syntax
#include "HLS/hls_float.h"
Description
Header file to provide FPGA-optimized arbitrary-precision IEEE 754 compliant floating-point number support.
To learn more, review the following tutorials:
  • <quartus_installdir>/hls/examples/tutorials/hls_float/1_reduced_doubl
  • <quartus_installdir>/hls/examples/tutorials/hls_float/2_explicit_arithmetic
  • <quartus_installdir>/hls/examples/tutorials/hls_float/3_conversions

hls_float_math.h Header File

Syntax
#include "HLS/hls_float_math.h"
Description
Header file to provide math functions for hls_float data types.
To learn more, review the following tutorials:
  • <quartus_installdir>/hls/examples/tutorials/hls_float/1_reduced_doubl
  • <quartus_installdir>/hls/examples/tutorials/hls_float/2_explicit_arithmetic
  • <quartus_installdir>/hls/examples/tutorials/hls_float/3_conversions

math_dsp_control.h Header File

Syntax
#include "HLS/math_dsp_control.h"
Description
Header file to provide the ihc::math_dsp_control function to control the hardware implementation for supported data types and math functions at a local-scope.

For control at a global-scope, use the --dsp-mode option of the i++ command.

To learn more, review the following tutorial: <quartus_installdir>/hls/examples/tutorials/best_practices/control_of_dsp_usage

stdio.h Header File

Syntax
#include "HLS/stdio.h"
Description
Provides printf support for components so that printf statements work in x86 emulations, but are disabled in component when compiling to an FPGA architecture.

Standard C++ <iostream> Header File

Syntax
#include <iostream>
Description
To use the C++ standard output streams (cout and cerr) provided by the standard <iostream> header, you must guard any standard output statements with the HLS_SYNTHESIS macro.

This macro ensures that statements in a component work in x86 emulations but are disabled in the component when compiling to an FPGA architecture.

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