Intel® High Level Synthesis Compiler Pro Edition: Reference Manual

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Date 6/02/2023
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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
1. Intel® HLS Compiler Pro Edition Reference Manual x
1.1. Pending Deprecation of the Intel® HLS Compiler
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® 7 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

13.17. Intel® HLS Compiler Pro Edition Memory-Mapped Interfaces

Use the mm_host object and template arguments to explicitly declare Avalon® Memory-Mapped (MM) Host interfaces for your component.

Table 57.   Intel® HLS Compiler Pro Edition Memory-Mapped Interfaces Summary
Template Object or Parameter Description
ihc::mm_host The underlying pointer type.
ihc::dwidth The width of the memory-mapped data bus in bits
ihc::awidth The width of the memory-mapped address bus in bits.
ihc::aspace The address space of the interface that associates with the host.
ihc::latency The guaranteed latency from when a read command exits the component when the external memory returns valid read data.
ihc::maxburst The maximum number of data transfers that can associate with a read or write transaction.
ihc::align The alignment of the base pointer address in bytes.
ihc::readwrite_mode The port direction of the interface.
ihc::waitrequest

Adds the waitrequest signal that is asserted by the agent when it is unable to respond to a read or write request.

getInterfaceAtIndex This testbench function is used to index into an mm_host object.

ihc::mm_host Template Object

Syntax
ihc::mm_host<datatype, template parameter >
Valid values
Any valid C++ datatype
Default Value
Default interface for pointer arguments.
Description
The underlying pointer type. Pointer arithmetic performed on the host object conforms to this type. Dereferences of the host results in a load-store site with a width of sizeof(datatype). The default alignment is aligned to the size of the datatype.

You can use multiple template arguments in any combination as long the combination of arguments describes a valid hardware configuration.

Example: 
component int dut(
 ihc::mm_host<int, 
   ihc::aspace<2>, ihc::latency<3>,
   ihc::awidth<10>, ihc::dwidth<32>
  > &a)
To learn more, review the following tutorials:
  • <quartus_installdir>/hls/examples/tutorials/interfaces/pointer_mm_host
  • <quartus_installdir>/hls/examples/tutorials/interfaces/mm_host_testbench_operators

ihc::dwidth Template Parameter

Syntax
ihc::dwidth<value>
Valid Values
8, 16, 32, 64, 128, 256, 512, or 1024
Default Value
64
Description
The width of the memory-mapped data bus in bits.

ihc::awidth Template Parameter

Syntax
ihc::awidth<value>
Valid Values
Integer value in the range 1 – 64
Default Value
64
Description
The width of the memory-mapped address bus in bits.

This value affects only the width of the Avalon® MM Host interface. The size of the conduit of the base address pointer is always set to 64-bits.

ihc::aspace Template Parameter

Syntax
ihc::aspace<value>
Valid Values
Integer value greater than 0.
Default Value
1
Description
The address space of the interface that associates with the host. Each unique value results in a separate Avalon MM Host interface on your component. All hosts with the same address space are arbitrated within the component to a single interface. As such, these hosts must share the same template parameters that describe the interface.

ihc::latency Template Parameter

Syntax
ihc::latency<value>
Valid Values
Non-negative integer value
Default Value
1
Description
The guaranteed latency from when a read command exits the component when the external memory returns valid read data. If this latency is variable (such as when accessing DRAM), set it to 0.

ihc::maxburst Template Parameter

Syntax
ihc::maxburst<value>
Valid Values
Integer value in the range 1 – 1024
Default Value
1
Description
The maximum number of data transfers that can associate with a read or write transaction. This value controls the width of the burstcount signal.

For fixed latency interfaces, this value must be set to 1.

For more details, review information about burst signals and the burstcount signal role in "Avalon Memory-Mapped Interface Signal Roles" in Avalon Interface Specifications.

ihc::align Template Parameter

Syntax
ihc::align<value>
Valid Values
Integer value greater than the alignment of the datatype
Default Value
Alignment of the datatype
Description
The alignment of the base pointer address in bytes.

The Intel® HLS Compiler uses this information to determine how many simultaneous loads and stores this pointer can permit.

For example, if you have a bus with 4 32-bit integers on it, you should use ihc::dwidth<128> (bits) and ihc::align<16> (bytes). This means that up to 16 contiguous bytes (or 4 32-bit integers) can be loaded or stored as a coalesced memory word per clock cycle.

Important: The caller is responsible for aligning the data to the set value for the align argument; otherwise, functional failures might occur.

ihc::readwrite_mode Template Parameter

Syntax
ihc::readwrite_mode<value>
Valid Values
readwrite, readonly, or writeonly
Default Value
readwrite
Description
The port direction of the interface. Only the relevant Avalon host signals are generated.

ihc::waitrequest Template Parameter

Syntax
ihc::waitrequest<value>
Valid Values
true or false
Default Value
false
Description
Adds the waitrequest signal that is asserted by the agent when it is unable to respond to a read or write request.

For variable-latency interfaces, you must set this value to true to prevent warnings or errors when you use Platform Designer to integrate your HLS component into your design.

For more information about the waitrequest signal, see "Avalon Memory-Mapped Interface Signal Roles" in Avalon Interface Specifications.

getInterfaceAtIndex Testbench Function

Syntax
getInterfaceAtIndex(int index)
Description
This testbench function is used to index into an mm_host object. It can be useful when iterating over an array and invoking a component on different indicies of the array. This function is supported only in the testbench.
Code Example 
int main() {
// …….
for(int idx = 0; idx < N; idx++) {
  dut(src_mm.getInterfaceAtIndex(idx));
}
// …….
}
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