DFL Language Training

1
Training Software Version v2.2
2
Training Overview

• Key Concepts
• Edit and Compile Source
• Create Architecture
• Map to Architecture
• Schedule Operations
• Build the RT-Level
• Verify the Design
• Create and Use a User Library
• Supported C subset

3
Key Concepts

• Edit and Compile Source
• Create Architecture
• Map to Architecture
• Schedule Operations
• Build the RT-Level
• Verify the Design
• Create and Use a User Library
• Supported C subset

4
Electronic Product Design
High-Complexity Applications
Time-2-Market
Time-2-Profit
Power-Efficient, High-Performance,
Cost-Effective, Flexible Architectures
Low-Cost
Low-Power
Deep-Sub-Micron Silicon Assembly
5
Design Flow
Algorithm
Architecture
RT-level Synthesis
Abstraction Levels
architecture
Gates
Layout
6
Time-to-Market

• Raising the abstraction level
• Code compactness
• Algorithmic description FIR filter
• 100 lines of C code
• RT-level description FIR filter
• 5,200 lines of HDL
• Blackbox
• Better simulation performance
• Easier design transfer and re-use

BEHAVIOR ( C SUBSET ) RT-LEVEL
7
Flexibility

• Optimal area for application
• Low-power design
• More processing power/throughput
• Same starting point
• FPGA
• ASIC
• cheaper custom solution

BEHAVIOR ( C SUBSET ) RT-LEVEL
8
Flexibility Example
RT-level synthesis
Behavioral synthesis
Reduction 50
Reduction 13
9
Application Area

• Data path elements are shared over clock cycles
• Moderate decision making is involved

Controller FSM
Control/ Flags
Control
Data Path Cores Register Files
RAM/ROM Addr/Data Regs
Address/ Data
10
Typical Applications

• ASSP Application Specific Standard Product
• Relatively complex data/signal processing
• GSM, DECT, wireless LAN
• Speech recognition, compression, processing
• JPEG, image processing
• Portable medical electronics
• ...

11
Design Constraints

• Design considerations
• Algorithm level
• Frame rate
• Frame 1 execution of your algorithm
• 1 frame consumes 1 value for each input, produces
  1 value for each output
• e.g. GSM LTP 1 data frame (160 samples) every 20
  ms
• Maximal latency delay on signal caused by the
  algorithm
• RT-level
• Clock rate
• e.g. 50 MHz clock
• Cycle budget Clock rate / Frame rate
• The amount of clock cycles available to execute
  one frame
• e.g. for GSM LTP 4000 cycles

12
Target Processor Architecture
branch logic
ALU
MULT
IN
OUT
RAM
ROM
13
Structure of a Cluster
14
Internal Design Flow
15
Internal Design Flow(2)
16
Defaults, Options and Pragmas

• Increasing order of priority
• Tool defaults
• Option settings (if any)
• Pragmas for specific cases

17
Hardware Libraries

• Default library
• Supplied by Frontier
• Two versions - for Xilinx FPGA flow
• - for ASIC flow
• Sufficient to map all supported C operators
• User libraries
• Existing hardware blocks
• Custom hardware blocks for better
  speed/area/power trade-off

18
Project organization
artd_cache
19

• Key Concepts
• Create Architecture
• Map to Architecture
• Schedule Operations
• Build the RT-Level
• Verify the Design
• Create and Use a User Library
• Supported C subset

Edit and Compile Source
20
Key Concept

• In a first step, ART Designer will convert in an
  intelligent way your behavior description of
  your algorithm into an internal representation.
• intelligent -gt it checks whether the code is
  C/C compliant, if there are non-synthesizable
  constructs present
• You can describe your algorithm using C/C
  optionally enriched by ART Library fixed-point
  types in C-style or SystemC-style.
• To use ART Library types
• include ltfxp.hgt / C/C
  version/
• include ltsc_fxp.hgt /SystemC
  version/

21
C Compiler optimizations

• Dead code elimination
• Constant propagation
• only for temporary expressions with constants
• b a 2 3 gt b a 5

22
C Compiler Options (1)
Specification of the include search path Multiple
entries are separated by semicolon Specification
is relative to project subdirectory
Example /home/john/include..MY_INCLUDES/incl
ude
Macros to be defined/undefined Semicolon
separated Example for Defines
FXPTRACEMY_DEFINE1
Enables C test bench generation I/O can be read
in binary or decimal format
Saves the source file obtained after CPP
processing
Enables strict ANSI C compliance
23
C Compiler Options (2)

• Data flow analysis
• identifies and accurately represents
• the parallelism of the C-code by
• - determining the exact data
• - dependencies between the variables
• to achieve - better performance
• - optimal use of target
  processor

24
Data Flow Analysis
void calc_address(const T_AD i, const T_AD
j, T_AD address) address const1i
const2j void mydesign() ... for (i0
ilt16 i) for (j0 jlt16 j)
calc_address(i,j,address) a Aaddress
.. // calculation of b Aaddress
b
DFA will check whether or not write address is
different from read address for every
iteration! This will determine how much loop
folding can be performed.
25
Pragmas in C Source

• pragma OUT ltvar_name_1gt ltvar_name_2gt
• Used to indicate function arguments that are
  strictly outputs
• This is not checked by the compiler !
• Example

26

• Key Concepts
• Edit and Compile Source
• Map to Architecture
• Schedule Operations
• Build the RT-Level
• Verify the Design
• Create and Use a User Library
• Supported C subset

Create Architecture
27
Key Concept

• In this step, you instantiate the hardware
  resources that you need to define the target
  architecture you want to use
• You only have to instantiate the central elements
  of hardware clusters (auxiliary resources like
  register files, muxes and tristate buffers are
  automatically generated at a later step)
• Cores (ALU, MULT, )
• Memories (RAM, ROM, )
• Ports (INPORT, OUTPORT)
• You also instantiate one type of controller

28
Architecture Model

29
Instantiating Resources

• Resources can be instantiated from
• The default library artd_library (for ASIC flow)
  or artd_xilinx_library ( for Xilinx FPGA flow)
• A user library
• The libraries must have been selected in the
  Create Architecture options

30
Resources in the Default Library (1)

• Cores
• alu, alusat,
• mult, multp, mac2, mac3
• acu
• Memories
• rom, ram
• romctrl
• dpram_r_w, dpram_r_rw, dpram_w_rw, dpram_rw_rw
• dprom, dpromctrl

31
Resources in the Default Library(2)

• Ports
• inport, inport_nohs, inport_noaddr,
  inport_noaddr_nohs
• outport, outport_nohs , outport_noaddr,
  outport_noaddr_nohs
• Controllers
• mbc_11, mbc_12, mbc_22, mbc_23

32
Pragma Syntax Table

• I integer (e.g. 10)
  
• IL integerlist (e.g. 10,20,6 )
  
• IW integer or wildcard (e.g. 10 or or _)
  
• C quoted string (e.g. "acu")
  
• CL quoted stringlist (e.g. "in18","in210")
• EXPR expression (e.g. __)

33
Pragmas (1)

• instantiate(C, C, C)
• instantiate(libraryName, resourceName,
  instanceName)
• This pragma instantiates a resource defined in a
  library
• The default library is called artd_library or
  artd_xilinx_library
• Multiple instances of the same resource can be
  created
• EXAMPLE
• instantiate("artd_xilinx_library","multp","multp_1
  ")
• instantiate("artd_library","mbc_12","ctrl")
• instantiate(my_own_library",multiplier",mymult"
  )

34
Pragmas (2)

• instantiate_function(C, C)
• instantiate_function(functionName,
  instanceName)
• This pragma instantiates a virtual resource, not
  defined in a library
• All calls to the named function will be mapped on
  this virtual resource as single-cycle operations
• Only a single function can be associated with a
  virtual resource
• Allows design exploration without actually having
  to create a library element
• EXAMPLE
• instantiate_function(cordic",cordic_1")

35
Pragmas (3)

• merge_regfiles(CL, C)
• merge_regfiles (registerfileName,
  newRegisterfileName)
• Merge a list of register files into a new
  register file with the specified name
• May lead to less registers but possibly a longer
  schedule
• EXAMPLE
  
• merge_regfiles("reg_a_ram_1","reg_dx_acu_1",
  addr_reg")

ram_1
ram_1
addr_reg
acu_1
acu_1
36
Pragmas (4)

• set_regfileports(C,IN,OUT, I)
• set_regfileports(regFileName,INOUT, nrports)
• This pragma allows you to generate multiport
  register files
• This pragma overrules the default register file
  settings of one input port and one output port
• EXAMPLE
  
• set_regfileports(merged_reg",IN,2)
• set_regfileports(merged_reg",OUT,2)
• This will result in a multiport register file
  called merged_reg with two input ports and two
  output ports

37
Pragmas (5)

• connect_bus(C, CL, CL)
• Connect_bus(busName, writer, reader)
• Allows you to define a bus and its connctions.
• With this pragma you can restrict resources from
  writing to specific busses or you can merge a
  number of busses into one single bus.
• By using multiple connect_bus pragmas you can
  define partial or a complete busnetwork. The
  outport of a resource that still has no bus
  connection after the last connect_bus pragma will
  automatically receive a private bus.
• EXAMPLE
  
• connect_bus( ram2_bus,acu_2dout,reg_a_ram
  _2d0,reg_dx_acu_2d0)
• Defines a bus called ram2_bus that is
  written to by the output of acu_2 and read by the
  address port of ram_2 and the first input port of
  acu_2

38
Pragmas (6)

• no_connection(C, CL)
• No_connection(writer, reader)
• With this pragma you can restrict connections
  between one output of a resource (defined by the
  first argument!) and a list of inputs.
• EXAMPLE
  
• no_connection( romctrl_1dout,reg_a_ram_2d0,
  reg_dx_acu_2d0)
• Using this pragma, no connection will be
  present between the output of romctrl_1 and the
  address register of ram_2 and the first input of
  acu_2

39
Default Architecture

• The following resources from the (ASIC)default
  library are automatically instantiated when a new
  project is created
• alu, mult
• acu
• romctrl
• ram, rom
• inport, outport
• mbc_23

40
Example Pragma File
//INPORT and OUTPORT without address
generation instantiate("artd_library","inport_noad
dr","inport_1") instantiate("artd_library","outpo
rt_noaddr","outport_1") //ACU and ROMCTRL for
RAM and ROM addressing instantiate("artd_library",
"acu","acu_ram") instantiate("artd_library","acu"
,"acu_rom") instantiate("artd_library","romctrl",
"romctrl_ram") instantiate("artd_library","romctr
l","romctrl_rom") //Cores and Memories instantiat
e("my_library","mac","my_mac") instantiate("artd_
library","rom","rom_1") instantiate("artd_library
","ram","ram_1") //Controller instantiate("artd_l
ibrary","mbc_23","ctrl") //dedicate address
generation cluster connect_bus(bus_romctrl_rom,
romctrl_romdout,reg__acu_romd0) connect
_bus (bus_dout_acu_rom,acu_romdout,reg__
acu_romd0, reg_a_acu_romd0) no_connection(
acu_ramdout,reg_a_rom_1) no_connection(r
omctrl_ramdout,reg__acu_rom,reg_a_rom_1
)
41
Views
Architecture view
42

views

• Architecture view
• Graphical representation of the selected
  architecture
• In this view you can select and highlight
  individual components and resources. You can also
  jump to the architecture report for a detailed
  textual overview

43
Reports (1)

• Architecture Report

44

Reports (2)

• Architecture report
• Lists all selected resource instances and its
  registers
• Lists for each instance/register
• input ports and connected register files/muxes
• output ports and connected buses
• Resources from the default library are listed
  with
• unspecified types and with their complete
  instructionset
• Resources from user libraries are listed with
  types
• and instruction list as specified in the
  library

45

• Key Concepts
• Edit and Compile Source
• Create Architecture
• Schedule Operations
• Build the RT-Level
• Verify the Design
• Create and Use a User Library
• Supported C subset

Map to Architecture
46
Key Concepts

• In the mapping step following tasks are
  performed
• Memory management variables and temporary
  variables (introduced by the compilation step)
  are allocated to the available memory resources
• Core resource assignment operations from the
  design are assigned to corresponding core
  resources and translated in RTs(register
  transfers)
• Multiplexer introduction muxes are introduced if
  more than 1 bus is connected to input of a
  register or if 2 or more variables with different
  types are transferred to that input over a bus
  connected to it

47
Memory Management
Access Speed
Addressed by Data path
RAM
Arrays
ROM
INPORT/OUTPORT
Area per Memory Location
48
Core resource assignment

• Resource assignment is completely detemined by a
  set of internal mapping rules and by user
  pragmas.
• The rules are divided in two groups
• First set applies to the mapping of the core
  resources in the default library. This set of
  rules are transparent for the user but not
  accessable
• The second set apply to the mapping of operations
  on user-defined resources and are an essential
  part of the pragmas of the corresponding
  user-defined library

49
Mapping rules

• Operations or instructions on resources from the
  standard library are handled as taking one clock
  cycle. Exception MAC (has a pipeline register)
• By default, operations and implicit operations
  are mapped to the first instance of a resource
  that can execute the operation
• First means first instantiated in pragma file of
  previous step
• Implicit operations
• - ROM/RAM addressing Initialize address,
  compute next address
• - FOR loops Initialize loop counter, update,
  test
• - Implicit constants for all instances

50
Multiplexer introduction

• In a last stage of the mapping step, muxes are
  introduced were needed.
• Their function is threefold
• bus selection
• data alignment
• type manupilation performed by coding
  cast operations

51
Pragmas (1)

• assign_expression(C, EXPR, C)
• assign_expression(scopeName, expression,
  instanceName)
• This pragma forces the mapping of operations,
  indicated with an expression, onto a particular
  instance
• The action of the pragma is restricted to the
  scope indicated by scopeName
  
• EXAMPLE
  
• assign_expression("/top",__,mult_2")
  
• All multiplications in top will be mapped on
  mult_2

52
Pragmas (2)

• assign_operation(C, C)
• assign_operation(operationName,
  instanceName)
• This pragma forces the mapping of operations,
  indicated with the hierarchical name or source
  label, on a particular instance
• The label needs to be specified using its full
  pathname
• Wildcard can be used in levels, in labels
• EXAMPLE
• assign_operation(/.../incri, acu_2)

void cordic () ... Uintlt4gt tmp_i 0 loopi for
(int i0 ilt14, i) incri tmp_i ...
53
Pragmas (3)

• assign_variable(C, C)
• assign_variable(variableName, instanceName)
• This pragma allows
  
• the mapping of a scalar or array variable onto a
  specific memory (RAM, ROM) or port (INPORT,
  OUTPORT)
• the mapping of constant variables onto a specific
  ROMCTRL memory
• The variable needs to be specified using its full
  pathname
• EXAMPLE
  
• assign_variable("/top/AX","ram_2")
  
• assign_variable("/c4","romctrl_3")
• assign_variable(/cordic/Q_in,inport_2)

54
Pragmas (4)

• assign_address(C, C)
• assign_address(variableName, instanceName)
• This pragma forces the address computation of a
  specific variable to be performed onto a
  particular instance
• If one of the operations needed for address
  computation cannot be performed on the given
  instance, the default (acu_1) is used instead
• EXAMPLE
  
• assign_address("/cordic/A","acu_2")

55
Pragmas (5)

• assign_loopcounter(C, C)
• assign_loopcounter(iteratorName,
  instanceName)
• This pragma forces the operations for the
  specified loopcounter (mostly decrement
  operations) to be performed onto the given
  instance
• The default resource is the first instantiated
  ACU
• EXAMPLE
  
• assign_loopcounter("/cordic/loopi/i","acu_2")

void cordic() ... loopi for (int i0 ilt14,
i) ...
56
Pragmas (7)

• unroll(C, IW, IW)
• unroll(loopName, firstIterationsToUnroll,
  lastIterationsToUnroll)
• This pragma unrolls loops or parts of loops
• Whole loop is unrolled when using the wildcard
  _
• EXAMPLE
• unroll(/cordic/loopi,_,_) // unrolls the
  whole loop
• unroll(/cordic/loopi,3,0) // unrolls the
  first 3 iterations
• unroll(/cordic/loopi,2,4) // unrolls first 2
  and last 4 iterations

void cordic() ... loopi for (int i0 ilt14
i) ...
57
Pragmas (8)

• assign_variable_to_port(C, C, C)
• assign_variable_to_port(variableName,
  instanceName, accessPortName)
• This pragma assigns all read/write operations of
  a variable to a specific port of a dual-port
  memory
• EXAMPLE
  
• assign_variable_to_port("/top/A",ram_1,ram_1_acce
  ss2")
• Assigns all accesses from/to array A to port 2 of
  ram_1

58
Pragmas (9)

• assign_operation_to_port(C, C, C)
• assign_operation_to_port(operationName,
  instanceName, accessPortName)
• This pragma assigns an operation to a specific
  port of a dual-port memory
• EXAMPLE
  
• assign_operation_to_port ("/top/loop/Aread",ram_1
  ,ram_1_access2")
• the read operation labeled Aread is done via
  access port 2 of ram_1

59
Reports

• Architecture report
• List of resource instances is reduced to those
  that are really used
• Instances from the default library
• types have been set to the maximal types that are
  used in the source
• instruction list has been reduced to those
  instructions that are used
• Instances from a user library
• actual types and rules have been checked versus
  the types and rules specified in the library
• The controller sizes are still unknown

60
Reports

• Memory map
• Detailed information on all
• present memory instances
• - RAM, ROM, ROMCTRL, INPORT, OUTPORT

61
Reports

• Mux Report
• Summary and detailed information
• on all multiplexers
• Type Report
• For all muxes
• - Output buses they are connected to
• - For each bus variables, types,
• bitwise connection and alignment

Two-way cross-highlighting with source!
62

• Key Concepts
• Edit and Compile Source
• Create Architecture
• Map to Architecture
• Build the RT-Level
• Verify the Design
• Create and Use a User Library
• Supported C subset

Schedule Operations
63
Key Concept

• In this fourth step, two tasks are performed
• Scheduling of the operations the resulting
  RT-graph will be ordered along a time axis in as
  few machine cycles as possible taking in account
  data and hardware constraints
• Register assignment variables will be assigned
  to fields of register files in such a way that
  the overall size of the register files is
  restricted to a minimum

64
List Scheduling
Candidate LIST
Conflict Priority Comp.
Scheduled Operation
INPUT

4
OUTPORT
MULT
ALU
INPORT
OUTPUT
5
65
ALAP and ALAP Greedy Scheduler
ALAP Greedy
ALAP
in
in
2
2
1
1




incx
incx
Parallel Path Optimizer Less Registers
5
5


8
8


4
4
9
9


decx
decx
7
7


incx
incx
out
out
66
Loop Folding (1)
1
2
3
1
2
3
X
X
X
CORE1
X
X
X
CORE1
-----
-----
CORE2
X
X
X
X
X
X
CORE2
X
1 cycle per iteration since there is no dependency
21 cycles
67
Loop Folding (2)

• Performed automatically
• Equivalent to pipelining
• Advantage
• Faster schedule through more parallelism
• Disadvantages
• Larger controller
• Larger register files

68
Register Assignment

• For a particular register file assignment of
  variables to specific register fields

0 1 2 3
a
d
field 1
b
e
e
field 2
c
f
field 3
69
Scheduler Options

• Scheduler algorithm
• ASAP (default) as soon as possible
• ALAP as late as possible
• ALAP Greedy complete paths are scheduled
• All tests them all for every level of
  hierarchy and takes the one which results in
  smallest cycle-count
• Unconstrained folding
• General option for all loops
• Default on scheduler will try to reduce the
  total machine-count of a for-loop by increasing
  the available parallelism within every iteration
• Can be overridden by pragma for specific loop

70
Pragmas (1)

• fold(C, I)
• fold(loopName, reductionLimit)
• For a specific loop, this pragma specifies the
  maximum number of iterations by which the
  original number of iterations may be reduced
• EXAMPLE
  
• fold("/cordic/loopi", 3)
  
• Iteration reduction of loop loopi" located in
  function cordic" due to folding is maximally 3.
  Suppose the original number of iterations is 14.
  After folding, the resulting number of iterations
  is at least 11.

71
Pragmas (2)

• max_cycles(C, I)
• max_cycles(scopeName, nrOfCycles)
• Only used for the calculation of the cycle count
  !
• Suppose scope C in the source hierarchy
  contains a conditional statement or a
  non-manifest loop .You can then specify a maximum
  cycle count value for scope C
• When the exact number of cycles needed for C
  can be computed, this pragma is ignored
• EXAMPLE
  
• max_cycles("/top/block1", 10)
• If the number of cycles needed to execute
  "/top/block1" cannot be computed exactly, a value
  of 10 will be assumed to calculate the cycle count

72
Views
Load view
73
Views

• Load view
• The top part shows the loop structure of the
  resulting schedule
• Height of vertical bars represents number of loop
  iterations
• The bottom part shows activity of cores, register
  files and/or buses as a function of the schedule
  (program counter)
• Dashed vertical lines represent loop and
  condition boundaries
• Colored vertical line shows split between init
  section and run section
• One-way cross-referencing to Schedule Report !
• Brings you to the potential, not to the exact RT

74
Views
made
consumed

• Lifetime view

75
Views

• Lifetime view
• The top part shows for selected register file(s),
  the lifetime of all variables stored in these
  files as a function of the schedule (program
  counter)
• The bottom shows for selected register file(s),
  the required number of fields as a function of
  the schedule
• One-way cross-referencing to Schedule Report !

76
Views

• RAM view

77
Views

• RAM view
• The lifetime of variables stored on the selected
  RAM(s) are displayed against the RAM (s)
  address space

78
Reports

• Schedule report

79
Reports

• Schedule report
• Detailed listing of all RTs and their relative
  sequence
• Two-way cross-referencing with source !
• Information on all I/O performed by the processor
  via INPORT and OUTPORT resources

80
Reports

• Cycle Count Report

81
Reports

• Cycle Count Report
• Information on number of cycles
• Exact number for manifest descriptions
• C program for non-manifest descriptions (except
  when using pragma max_cycles)
• Information on loop structure of the input
  description

82
Reports

• Register report

83
Reports

• Register report
• Summary overview of register usage
• Detailed listing for all register files and all
  fields
• Variables stored in the register field
• For each variable, potentials at which writes and
  reads occur

84

• Key Concepts
• Edit and Compile Source
• Create Architecture
• Map to Architecture
• Schedule Operations
• Verify the Design
• Create and Use a User Library
• Supported C subset

Build the RT-Level
85
Key Concepts

• In this last step, following is performed
• Controller generation
• ROM optimizations
• HDL generation

86
Controller-based versus Hardwired
Algorithm a x y - zc Controller-based
implementation (e.g. with microprogram)
microprogram 1. zctmp1 2 y-tmp1tmp2 3.
Xtmp2a
Hardwired implementation

x
-
y
z
a

c
87
Multi-branch versus Single-Branch
Single-branch code
if (ingt8) result 3 else if (ingt4)
result 2 else if (ingt2) result
1 else result 0
Consecutive conditional jumps
Multiple-branch code
switch (in) case large result 3
break case medium result 2 break
case low result 1 break
default result 0
Offers a large number of possible next addresses
1
88
Controller Generation
Generates the control bits sent to the different
resources of the datapath
Evaluates boolean combinations of its inputs
(status flags). Output condition code
Decodes the condition code to decide if the PC
has to branch to a specific address. Output
encoded jump address
89
Controller Alternatives (1)

• mbc_23 (default)

90
Controller Alternatives (2)

• mbc_22
• This is a variation on the default controller
• difference a pipeline stage (status) has been
  removed

91
Controller Alternatives (3)

• FSM-based the microcode is replaced with a
  synthesizable HDL model
• mbc_11

92
Controller Alternatives(4)

• mbc_12 control delay of 2

93
Optimizations

• Optimization of micro-ROM
• Removal of columns constant columns and
  duplicate columns are removed

Before Optimization
After Optimization
1 0 1 1 0 1 0 1 1 1 1 0 0 0
1 1 0 0 0 1
1 0 1 1 0 1 0 1
Res. 1
Res. 2
Res. 1
Res. 2
GND
VDD
94
Optimizations

• Optimization of ROMCTRLs
• Constants are put in micro-ROM if the number of
  micro-ROM columns is not increasing

95
HDL Netlist Structure

• Hierarchical design

artd_ltdesigngt_microrom
artd_ltdesigngt
StatusLogic
artd_rom
Controller
BranchLogic
ir
Cores, ports, auxiliary resources
alu_1
Busses
96
Options

• Netlist manipulations
• processor init choose to have it internal or
  external
• optimize dataROM
• Generate Hold pin to freeze the processor state
• Separate files generates separate HDL files
  instead of
• 1 large HDL file

97
Pragmas (1)

• optimize_dataroms(CL, ON, OFF)
• optimize_dataroms(romOrRomctrlInstanceName,
• ON, OFF)
• Overrules the Options setting for a specific ROM
  or ROMCTRL
• EXAMPLE
  
• optimize_dataroms("rom_", ON)
  
• Optimizes contents of all ROM instances whose
  names start with rom_
• optimize_dataroms("romctrl_1","rom_1", OFF)
  
• No optimization of contents of romctrl_1 and rom_1

98
Pragmas (2)

• define_vhdl_generic(C, C, C, C)
• define_vhdl_generic(vhdlinstancePathName,
  genericName, genericType, genericValue)
• Suppose you have your own VHDL core with
  generics. This pragma allows you to supply the
  additional information needed to instantiate the
  core in the VHDL netlist
• You have to specify such a pragma for every
  generic
• EXAMPLE
  
• define_vhdl_generic(mymult_1", "width1",
  "integer", "8")
• The generic width1 of type "integer" of the
  instance mymult_1" will be set to the value "8"

99
Pragmas (3)

• define_verilog_parameters(C, C)
• define_verilog_parameters(veriloginstancePathName
  , parameterArgumentValues)
• Suppose you have your own Verilog core with
  parameters
• This pragma allows you to specify the values
  of this parameters for an instantiate of the core
  in the Verilog netlist
• EXAMPLE
  
• define_verilog_parameters(mymult_1", "8, 7")
  
• The parameter string "8, 7" will be used for
  the instantiation of mymult_1 in the Verilog
  netlist

100
Pragmas (4)

• make_external(CL)
• make_external(compomentName)
• The full instance pathname has to be specified
  (see examples)
• EXAMPLES
  
• make_external("rom")
  
• makes all instances external whose names start
  with rom
• make_external(reg_dy_alu_1)
• makes register file for the Y input of alu_1
  instance external
• make_external(mult_1")
  
• makes mult_1 and its associated registers and
  multiplexers external

101
Pragmas (5)

• inport_benchmode(C, READONCE,READONCEPERFRAME)
• For a specific INPORT, provides more flexibility
  for reading input values within the test bench
• Address generation on
• Default each stimuli file is read once per frame
• By selecting READONCE, the stimuli file is only
  read in the first frame
• The read value(s) will be reused in the next
  frames
• E.g. useful for constant parameter values
• Address generation off
• Default stimuli file is read every time a read
  operation is encountered
• By selecting READONCEPERFRAME, the stimuli file
  will only be read once per frame
• Only supported if only one variable is mapped on
  the INPORT instance
• EXAMPLE inport_benchmode("inport_1",READONCE)

102
Pragmas (6)

• map_rom_on_lutram(romInstanceName)
• map_ram_on_lutram(ramInstancename)
• Indicates wheter the ROM/RAM will be mapped on a
  network of lut rams
• This pragma will only be effective if you have
  chosen in the create architecture step for the
  Xilinx FPGA flow
• EXAMPLE map_ram_on_lutram(ram_1)

103
Pragmas (7)

• map_rom_on_blockram(C,I)
• map_ram_on_blockram(C,I)
• Map_rom_on_blockram(romInstanceName,
  max_nr_blockrams)
• Map_ram_on_blockram(ramInstanceName,
  max_nr_blockrams)
• Indicates wheter the ROM/RAM will be mapped on a
  network of blockrams and LUT rams
• This pragma will only be effective if you have
  chosen in the create architecture step for the
  Xilinx Virtex or Spartan II flow
• EXAMPLE map_ram_on_blockram(ram_1,4)
• Maps ram_1 on a combination of
  block ram and lut ram.
• At most 4 block rams may be
  used. Lut rams will only be used
• if there are not enough block
  rams.

104
Reports

• Architecture report
• Controller dimensions are
• now filled in

105

• Key Concepts
• Edit and Compile Source
• Create Architecture
• Map to Architecture
• Schedule Operations
• Build the RT-Level
• Create and Use a User Library
• Supported C subset

Verify the Design
106
Fetching Inputs with INPORT
Ports generated on processor for every INPORT
ART Designer Processor
ltinport_namegt_address
(not for inport_noaddr)
ltinport_namegt_ data
External Memory Device
ltinport_namegt_ dreq
ltinport_namegt_ davail
107
Writing Outputs with OUTPORT
Ports generated on processor for every OUTPORT
ART Designer Processor
ltoutport_namegt_address
(not for outport_noaddr)
External Memory Device
ltoutport_namegt_ data
ltoutport_namegt_ dready
ltoutport_namegt_ daccept
108
Processor Control Pins
clk
ART Designer Processor
ready
rst
start
109
Processor Startup Sequence
110
Timing of Processor I/O
Meaning of the ready flag
Timing of Input Signals
Timing of Output Signals
111
Generated HDL Test Bench
112
Verifying the Generated HDL

• Example for vsim and Unix
• go to the artd_vhd or artd_v subdirectory
  of your project
• vlib work
• vcom artd_design.vhd artd_bench.vhd
• vsim artd_bench -c -do run -all quit -f

113

• Key Concepts
• Edit and Compile Source
• Create Architecture
• Map to Architecture
• Schedule Operations
• Build the RT-Level
• Verify the Design
• Supported C subset

User Libraries
114
Using your own Data Path Resources
void addsub (const Intlt16gt in1, const Intlt16gt
in2, const Uintlt1gt mode, Intlt16gt out)
pragma OUT out if (mode 0) out
in1 in2 if (mode 1) out
in1- in2
mode
You need to define -I/O -instructionset -timing
1 bit
16 bits
in1
Add Sub
16 bits
out
16 bits
in2
time
115
Constraints on User Library Resources

• You can only create user-defined resources that
  perform arithmetic or logical operations on their
  inputs
• types of arguments have to be determined
• Latency (number of cycles) has to be manifest

116
Library Data Organization
Contains info about the contents and the
parameters of the library
For every resource you need a pragma file with
the ART Designer model
Optional HDL description of every resource for
simulation/synthesis
117
Declaring a User Library

• Use the Create Architecture options
• Library Name
• Symbolic name to be used in pragmas
• Library Path
• Actual directory for library data

118
Creating a User Library

• To create a user-library, ART Designer is
  equipped with a Library Manager
• ToolsgtLibrary Manager

119
Adding resources

• Once you have created the user-library, you have
  to add resources to that library
• ResourcegtNew

Resource Name
Origin ART Builder or user supplied
Pin availability and their names
Model availability and names
120
Necessary pragmas for every resource

121
Pragmas (1)

• define_view(CORE, C)
• define_view(CORE,resourceName)
• Defines a name for the user-defined resource
• EXAMPLES
• define_view (CORE,myMult")

122
Pragmas (2)

• define_inputs(C, CL)
• define_inputs(resourceName, inputPort)
• Defines the name and the width of each input.
• Control input (command bus) can also be specified
  here
• Up to two command busses can be present
• EXAMPLE
• define_inputs(cordiccore", I_in8",
  Q_in8")
• define_inputs(myBlock, in124, in224,
  Cbus3)

Command bus
123
Pragmas (3)

• define_outputs(C, CL)
• define_outputs(resourceName, outputPort)
• For a specific resource, this pragma defines the
  name and the width of each data output
• Flag outputs can also be specified here
• EXAMPLE
• define_outputs(myBlock", xi16, xq16,
  xp16")
• define_outputs(myOwnAlu, out16, flag11,
  flag21)

124
Pragmas (4)

• define_instruction(C, C, CL)
• define_instruction(resourceName,
  instructionName, control)
• This pragma allows you to define an instruction,
  along with its control bits
• default instruction must always be defined
• Will be applied for the clock cycles when the
  resource is not active
• Important for resources with internal state
• EXAMPLE
• define_instruction(myAlu", "add", "CbusFTT")
• define_instruction(myBlock, default, )
• / single-mode block without internal state /

125
Pragmas (5)

• define_singlecycle_reservationGraph(C, C) or
• define_pipelined_reservationGraph(C, C) or
• define_multicycle_reservationGraph(C, C)
• The pragmas define different reservationgraphs
  which can be applied to specific instructions
• There are 3 possible predefined
  reservationgraphs
• - single cycle, pipelined and multicycle
• It is also possible to create your own
  reservationgraph using the define_reservationGrap
  h pragma in combination with other optional
  pragmas
• EXAMPLE
• Define_pipelined_reservationGraph(myMult",
  onepipelinestage")

126
Pragmas (6)

• map_function(C, C, C,CL, CL, CL)
• Map_function(funcName, resourceName,
  reservationGraph,
• inputMapping, outputMapping,
  ctrlMapping)
• This pragma defines how a function is mapped on a
  resource. It calls the function and maps it
  onto the first instance of this type of resource.
• EXAMPLE
• define_rule (mult",mymult,onepipelinestage
  "in1","in2", "out1","FlagZ",
  modedefault)

127
Optional Pragmas

• map_expression(EXPR, C, C, CL,CL,CL)
• Map_expression(expression,resourceName,
  reservationGraph, inputmapping,
  outputmapping, ctrlMapping)
  
• This pragma allows you to map expression with
  type definition! on a user-defined resource
• EXAMPLE
• map_expression(Intlt32gt9(Intlt32gt(_) Intlt32
  (_)),myMult", resgraph", in1,in2,
  out,flagZ,modedefault)

128
Optional Pragmas

• define_pipeline(C ,I)
• define_pipeline(timeshapeName, nrOfPipeRegs)
  
• This pragma defines a pipelined timeshape that
  can be applied to a resource with pipeline
  registers
• The instruction(s) with this timeshape and the
  inputs need to be applied during a specific
  cycle, the corresponding output appears after the
  specified number of pipelines 1
• EXAMPLE
• define_pipeline("multTimeshape", 1)

129
Optional Pragmas

• define_sideeffect(C ,IL)
• define_sideeffect(resourceName,instruction)
  
• For resources with internal state, this pragma
  defines which instructions change the state
• Used by speculation and loopinvariant code
  optimizers
• EXAMPLE
• define_sideeffect(userMac2, mac, mpy)

130
Optional Pragmas

• define_alignment(resourceName ,LSB,MSB)
• This pragma defines how all operands and
  operations will be aligned on the ports of
  resource
• No mixed alignment is allowed. LSB alignment is
  the default.
• EXAMPLE
• define_aligment("myMult", MSB)

131
Example Pragma Set (1)
define_view(CORE,"acs") define_inputs("acs",
"in116","in216","in316","mode2") define_out
puts("acs","out116","out216","out31","out41"
) define_instruction("acs","default","modeFF"
) define_instruction("acs","nMax1","modeFT")
define_instruction("acs","pMax2","modeTF") def
ine_instruction("acs","nMax2","modeTT") Defin
e_singlecycle_reservationGraph(acs,graph)
define_rule( "pMax1", acs,graph,
"in1","in2","in3","out1","out2","out3","out4",
modedefault) define_rule( "nMax1",
acs,graph, "in1","in2","in3","out1","out2",
"out3","out4",modenMax1) define_rule(
"pMax2", acs,graph, "in1","in2","in3","out1
","out2","out3","out4",modepMax2) define_ru
le( "nMax2", acs,graph, "in1","in2","in3","
out1","out2","out3","out4",modenMax2)
132
Example Pragma Set (2)

• Defines a resource acs with
• 3 data inputs
• 1 control input
• 4 data output
• Defines 4 instructions that can be mapped on this
  resource
• All instructions take a single cycle to execute

133
User-defined Libraries

• Running ART Designer
• Needed pragma file that models I/O,
  instructions and timing
• Performing C simulation of your algorithm
• Needed
• Either a behavioral model in C for the complete
  block ...
• Or a separate behavioral model in C for each
  instruction (recommended)
• Performing RTL HDL simulation and/or synthesis
• Needed HDL model

134

• Key Concepts
• Edit and Compile Source
• Create Architecture
• Map to Architecture
• Schedule Operations
• Build the RT-Level
• Verify the Design
• Create and Use a User Library

Supported C subset
135
Constant Definition

• A warning is generated when an overflow or
  quantization occurs during compilation
• Example
• Fixlt12,9gt coef -1.70171875Generates the
  following warning Quantization occurred when
  casting the constant "-1.701718749999999900e00"
  to the type fixlt12,9gt".Result is
  "0bt110.010011000" ( "-1.703125" )
• String literals are only supported for the
  initialisation of ART Library type
  variables.Example Ufixlt5,2gt c0bu011.01

136
Enumeration Constants

• Identifiers declared as enumerators are treated
  as integer constants.
• Renumbering is possible.
• ART Designer will use the smallest possible type
  to represent the enumeration.
• Example enum State(INIT, EXEC, OUTPUT) State
  states
• gt Internally, the variable states will be
  represented as a 2-bit variable

137
Data-Types (1)

• The standard C types are mapped into ART Library
  types before being mapped into an internal
  representation

C Type
ART Library Type
signed char
Fixlt8,0gt
unsigned char
Ufixlt8,0gt
Fixlt16,0gt
signed short int
unsigned short int
Ufixlt16,0gt
signed int
Fixlt32,0gt
unsigned int
Ufixlt32,0gt
signed long int
Fixlt32,0gt
unsigned long int
Ufixlt32,0gt
bool
Uintlt1gt
void
Not mapped
138
Data-Types (2)

• The C types float, double, long double are NOT
  supported
• Pointers and pointer arithmetic are NOT
  supported, use arrays instead
• Arrays with incomplete type descriptions are not
  supported Intlt10gt A5 // is erroneous
• A structure is expanded into its member
  valuesExample struct algoState long
  buffer char offset struct algoState
  s1 The corresponding HDL variables will
  be s1xbuffer and s1xoffset

Consequence An array of a structure with N
elements is represented as N
different arrays.
139
Data-Types (3)

• If structures are used as input or output to the
  top function or an ASU, you will get extra inputs
  or outputs in the generated HDL.
• The bit information for bit-field structure
  members is ignored.Example struct PPN
  unsigned int PFN 22 int 4
  //unused unsigned int CCA 3 bool dirty
  1 bool valid 1 bool global 1
• Union types are NOT supported.Example union
  value char s int i

140
Expressions

• All C operations mapped on resources out of the
  default library will get the quantization
  characteristic TRUNCATED and the overflow
  characteristic WRAPPED.
• This corresponds to the default behavior of
  ART Library.
• ART Designer only supports the following
  non-default characteristics
• , - with saturate
• The division / and modulo operator are NOT
  supported.
• Special modulo can be performed on the ACU by
  using the predefined functions of ltartd_acu.hgt
• A shift operation with a negative shift value
  shifts in the opposite direction.
• Recursive function calls are NOT supported

141
Declarations Initialization

• Declarations
• The volatile type qualifier is ignored
• The register class specifier is ignored
• Initialization
• Initialization of static variables by using a
  function argument is not supported.Intlt16gt
  func(Intlt8gt in) static Intlt8gt tempin //
  erroneous
• Non-initialized static fixed-point variables get
  a dontcare value.
• Static and global variables having a supported C
  type and which are not explicitly initialized,
  are initialized to zero according to the C
  semantics. ART Designer will automatically
  initialize such variables to zero.

142
Function Declarations (1)

• Defining the I/O arguments (for top function and
  for functions mapped to resources)
• return argument (if present) output
• non-pointer type argument input
• reference or array type arguments will be mapped
  on an input and output argument. However, this
  input and output argument can be removed
• Input only use the const qualifier
• const Intlt8gt sample3
• Output only use the pragma precompiler
  directive
• ifdef__SYNTHESIS__
• pragma OUT ltargument_name_1gt ltargument_name_2gt
  
• endif

143
Function Declarations (2)

• Example

include ltfxp.hgt void adder( const Intlt4gt a,
//const is optional const Intlt4gt b, //const
is optional Intlt4gt c ) pragma OUT c
cab
entity adder is port ( a in
std_logic_vector(3 downto 0) b in
std_logic_vector(3 downto 0) c out
std_logic_vector(3 downto 0) ) end adder
Inputs a and b, outputs c
144
Linkage Preprocessing

• A linking step is NOT supported by ART Designer,
  consequences are
• The input may be kept in several files, but they
  have to be included in the file containing the
  top function
• External functions are not supported
• External variables are not supported (extern
  specifier)
• PreprocessingThe preprocessor variable
  __SYNTHESIS__ is automatically set by ART
  Designer and can be used to exclude some parts of
  the C specification from the mapping.Example i
  fndef __SYNTHESIS__ printf(I am debugging\n)
  // NOT mapped by ART Designer endif

145
Bit Operations

• All bit operations in ART Library are supported
• concatenation
• z concat(x,y)
• bit select or bit set
• z bit(x,pos)
• bit(z,pos,x)
• slice select or slice set
• z slice(x,pos1,pos2)
• slice(z,pos1,pos2,x)
• They may result in non-optimal hardware since
  they are mapped into basic operations

146
Other Constructs

• The goto statement is NOT supported
• The standard library is NOT supported
• stdio.h in C
• iostream.h in C

147
Coding Guidelines (1)

• Type definitionsUse typedef instead of define.
  This results in cleaner and safer code.Example
  typedef Fixlt22,21gt D_FIX D_FIX
  a0.75

148
Coding Guidelines (2)

• Fixed-point variables constructed f