Intel® High Level Synthesis Compiler Pro Edition: Reference Manual

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Date 12/13/2021
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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

11.4.1.4. Object Manifest File Syntax

The HLS library object manifest file is an XML file that maps the RTL modules in a library object to functions that can be called by your HLS code. The Intel® HLS Compiler uses the properties defined in the manifest file to integrate an RTL module into the component pipeline.

The following example show a simple object manifest file for an RTL module that implements a double-precision square root function. The RTL module is implemented in VHDL with a Verilog wrapper.

The following object manifest file is for an RTL module named my_fp_sqrt_double (line 2) that implements a callable function with a C interface named my_sqrtfd (line 2). 

 1: <RTL_SPEC>
 2:   <FUNCTION name="my_sqrtfd" module="my_fp_sqrt_double">
 3:     <ATTRIBUTES>  
 4:       <IS_STALL_FREE value="yes"/>
 5:       <IS_FIXED_LATENCY value="yes"/>
 6:       <EXPECTED_LATENCY value="31"/>
 7:       <CAPACITY value="31"/>
 8:       <HAS_SIDE_EFFECTS value="no"/>
 9:       <ALLOW_MERGING value="no"/>
10:       <PARAMETER name="WIDTH" value="64"/>
11:     </ATTRIBUTES> 
12:     <INTERFACE>
13:       <AVALON port="clock" type="clock"/>
14:       <AVALON port="resetn" type="resetn"/>
15:       <AVALON port="ivalid" type="ivalid"/>
16:       <AVALON port="iready" type="iready"/>
17:       <AVALON port="ovalid" type="ovalid"/>
18:       <AVALON port="oready" type="oready"/>
19:       <INPUT port="datain" width="64"/>
20:       <OUTPUT port="dataout" width="64"/>
21:     </INTERFACE>
22:     <REQUIREMENTS>
23:       <FILE name="my_fp_sqrt_double_s5.v" />
24:       <FILE name="fp_sqrt_double_s5.vhd" />
25:     </REQUIREMENTS>
26:     <RESOURCES>
27:       <ALUTS value="2057"/>
28:       <FFS value="3098"/>
29:       <RAMS value="15"/>
30:       <MLABS value="43"/>
31:       <DSPS value="1.5"/>
32:     </RESOURCES>
33:   </FUNCTION>
34: </RTL_SPEC>
Table 28.  Elements and Attributes in the Object Manifest File
XML Element Description
RTL_SPEC Top-level element in the object manifest file. There can only be one such top-level element in the file.
FUNCTION

Element that defines the HLS function that the RTL module implements. The name attribute within the FUNCTION element specifies the function name.

You might have multiple FUNCTION elements, each declaring a different function that you can call from the HLS component.

The same RTL module can implement multiple functions by specifying different parameters. To use the same module with different parameter combinations, create a separate FUNCTION tag for each parameter combination.

ATTRIBUTES Element that contains other XML elements that describe various characteristics (for example, latency) of the RTL module.

The example RTL module takes one PARAMETER setting named WIDTH, which has a value of 64.

See for more details other ATTRIBUTES-specific elements.

If you create multiple RTL-based functions using different modules or use the same RTL module with different PARAMETER settings, you must create a separate FUNCTION element for each function.

INTERFACE Element that contains other XML elements that describe the RTL module interface.

The example object manifest file shows the streaming interface signals that every RTL module must provide (that is, clock, resetn, ivalid, iready, ovalid, and oready).

The resetn signal is active low. Its synchronicity depends on the target device:
Intel® Agilex™
The resetn signal is synchronous to the clock signal. For more information about reset signal timing, see Intel Agilex and Intel Stratix 10 Design-Specific Reset Requirements for Stall-Free and Stallable RTL Modules.
Intel® Arria® 10
The resetn signal is asynchronous to the clock signal.
Intel® Stratix® 10
The resetn signal is synchronous to the clock signal. For more information about reset signal timing, see Intel Agilex and Intel Stratix 10 Design-Specific Reset Requirements for Stall-Free and Stallable RTL Modules.

The signal names must match the ones specified in the RTL module properties file. An error occurs during library creation if a signal name is different in the RTL code and the RTL module properties file.

REQUIREMENTS Element that specifies one or more RTL resource files (that is, .v, .sv, .vhd, .hex, and .mif). The specified paths to these files are relative to the location of the object manifest file. Each RTL resource file becomes part of the associated Platform Designer component that corresponds to the entire HLS component.

HLS libraries do not support .qip files.

RESOURCES Optional element that specifies an estimate of the FPGA resources that the RTL module uses. If you do not specify this element, the estimated FPGA resources that the RTL module uses defaults to zero in the HLS resource estimation report.
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