Handel-C
Developer | ESL; Celoxica; Agility; Mentor Graphics; Siemens EDA |
---|---|
First appeared | 1996 |
Stable release | v3.0
|
Cross-platform (multi-platform) | |
Filename extensions | .hcc, .hch |
Website | eda |
Major implementations | |
Celoxica DK http://192.168.100.187 | |
Influenced by | |
C, CSP, occam |
Handel-C is a
Unlike many other hardware design languages (HDL) that target a specific computer architecture Handel-C can be compiled to a number of HDLs and then synthesised to the corresponding hardware. This frees developers to concentrate on the programming task at hand rather than the idiosyncrasies of a specific design language and architecture.
Additional features
Handel-C's subset of C includes all common C language features necessary to describe complex
Parallel programs
In order to facilitate a way to describe
For example:[1]
par {
++c;
a = d + e;
b = d + e;
}
Channels
Channels provide a mechanism for message passing between parallel threads. Channels can be defined as asynchronous or synchronous (with or without an inferred storage element respectively). A thread writing to a synchronous channel will be immediately blocked until the corresponding listening thread is ready to receive the message. Likewise the receiving thread will block on a read statement until the sending thread executes the next send. Thus they may be used as a means of synchronizing threads.[1]
par {
chan int a; // declare a synchronous channel
int x;
// begin sending thread
seq (i = 0; i < 10; i++) {
a ! i; // send the values 0 to 9 sequentially into the channel
}
// begin receiving thread
seq (j = 0; j < 10; j++) {
a ? x; // perform a sequence of 10 reads from the channel into variable x
delay; // introduce a delay of 1 clock cycle between successive reads
// this has the effect of blocking the sending thread between writes
}
}
Asynchronous channels provide a specified amount of storage for data passing through them in the form of a
A thread may simultaneously wait on multiple channels, synchronous or asynchronous, acting upon the first one available given a specified order of priority or optionally executing an alternate path if none is ready.
Scope and variable sharing
The scope of declarations are limited to the code blocks ({ ... }
) in which they were declared, the scope is hierarchical in nature as declarations are in scope within sub blocks.[1]
For example:
int a;
void main(void)
{
int b;
/* "a" and "b" are within scope */
{
int c;
/* "a", "b" and "c" are within scope */
}
{
int d;
/* "a", "b" and "d" are within scope */
}
}
Extensions to the C language
In addition to the effects the standard semantics of
Types and Objects | Expressions | Statements |
---|---|---|
chan | < ... > (type clarifier) | ! (send into channel) |
chanin | [ : ] (bit range selection) | ? (read from channel) |
chanout | \\ (drop) | delay |
macro expr | <- (take) | ifselect |
external | @ (concatenation operator) | set intwidth |
external_divide | select | let ... ; in |
inline | width | par |
interface | prialt | |
internal | releasesema | |
internal_divide | set clock | |
mpram | set family | |
macro proc | set part | |
ram | set reset | |
rom | seq | |
sema | try { ... } reset | |
shared | trysema | |
signal | with | |
typeof | ||
undefined | ||
wom |
Scheduling
In Handel-C, assignment and the delay command take one cycle. All other operations are "free".
History
The historical roots of Handel-C are in a series of
Handel-C was adopted by many University Hardware Research groups after its release by ESL, as a result was able to establish itself as a hardware design tool of choice within the academic community, especially in the United Kingdom.
In early 2008, Celoxica's ESL business was acquired by Agility, which developed and sold, among other products, ESL tools supporting Handel-C.
In early 2009, Agility ceased operations after failing to obtain further capital investments or credit[2]
In January 2009, Mentor Graphics acquired Agility's C synthesis assets.[3]
Other subset C HDL's that developed around the same time are Transmogrifier C in 1994 at University of Toronto (now the FpgaC open source project) and Streams-C at Los Alamos National Laboratory (now licensed to Impulse Accelerated Technologies under the name Impulse C)
See also
References
- ^ a b c d e "Archived copy" (PDF). Archived from the original (PDF) on 2010-03-31. Retrieved 2010-03-31.
{{cite web}}
: CS1 maint: archived copy as title (link) Handel-C Language Reference Manual - ^ Gabe Moretti (19 January 2009). "Agility DS victim of credit crunch". EETimes.com.
- ^ Dylan McGrath (22 January 2009). "Mentor buys Agility's C synthesis assets". EETimes.com.
External links
- Handel-C language resources at Mentor Graphics
- Oxford Handel-C
- Ahmed Ablak; Issam Damaj; American University of Kuwait (2016). "HTCC: Haskell to Handel-C Hardware Compiler". 2016 Euromicro Conference on Digital System Design (DSD). pp. 192–199. S2CID 13213191.