fpga: sim: Add PkgComplex, PkgMath, and PkgRandom

PkgComplex adds functions for doing complex arithmetic in SystemVerilog
simulation.

PkgMath provides mathematical operations and constants that aren't
built into SystemVerilog, such as a constant for pi and the function
round().

PkgRandom adds randomization functions beyond what standard Verilog
supports but that don't require any special licenses or simulators.


Original-commit: da4202e6f74796603072aa14544581604e81df02
This commit is contained in:
Wade Fife
2021-08-08 14:59:26 -05:00
parent 3a6961a3f4
commit acc8486ac1
5 changed files with 546 additions and 0 deletions
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#
# Copyright 2021 Ettus Research, A National Instruments Brand
#
# SPDX-License-Identifier: LGPL-3.0-or-later
#
SIM_PACKAGES_SRCS = $(abspath $(addprefix $(BASE_DIR)/../sim/packages/, \
PkgMath.sv \
PkgComplex.sv \
PkgRandom.sv \
))
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//
// Copyright 2021 Ettus Research, A National Instruments Brand
//
// SPDX-License-Identifier: LGPL-3.0-or-later
//
// Package: PkgComplex
//
// Description:
//
// A package for doing complex arithmetic in SystemVerilog simulations.
// Fixed-point operations are implemented such that results clip to the range
// [-1.0, 1.0) and are rounded to the nearest ULP (half ULP is rounded away
// from zero, following SystemVerilog rounding behavior).
//
package PkgComplex;
//---------------------------------------------------------------------------
// Type Definitions
//---------------------------------------------------------------------------
// Define a signed 16-bit fixed-point type with 15 fractional bits (Q0.15).
typedef bit signed [15:0] s16_t;
// Signed complex 16-bit data type, the standard type used by UHD and RFNoC.
typedef struct packed {
s16_t re;
s16_t im;
} sc16_t;
// Complex floating point data type.
typedef struct {
real re;
real im;
} complex_t;
// Maximum and minimum allowed by the s16 type.
localparam s16_t MAX_S16 = 16'h7FFF;
localparam s16_t MIN_S16 = 16'h8000;
//---------------------------------------------------------------------------
// Conversion Functions
//---------------------------------------------------------------------------
// Create an sc16 value from two s16 values.
function sc16_t build_sc16(s16_t x = 0, s16_t y = 0);
sc16_t val;
val.re = x;
val.im = y;
return val;
endfunction : build_sc16
// Create a complex value from two real values.
function complex_t build_complex(real x = 0.0, real y = 0.0);
complex_t val;
val.re = x;
val.im = y;
return val;
endfunction : build_complex
// Convert s16 to real.
function real s16_to_real(s16_t x);
return real'(x) / (2.0**15);
endfunction : s16_to_real
// Convert real to s16.
function s16_t real_to_s16(real x);
real val;
val = x * (2.0**15);
val = (val > MAX_S16) ? MAX_S16 : val;
val = (val < MIN_S16) ? MIN_S16 : val;
return s16_t'(val);
endfunction : real_to_s16
// Convert complex to sc16.
function sc16_t complex_to_sc16(complex_t x);
sc16_t val;
val.re = real_to_s16(x.re);
val.im = real_to_s16(x.im);
return val;
endfunction : complex_to_sc16
// Convert sc16 to complex.
function complex_t sc16_to_complex(sc16_t x);
complex_t val;
val.re = s16_to_real(x.re);
val.im = s16_to_real(x.im);
return val;
endfunction : sc16_to_complex
// Convert polar coordinates to a complex number. The phase should be in
// radians.
function complex_t polar_to_complex(real mag, real phase);
complex_t val;
val.re = mag * $cos(phase);
val.im = mag * $sin(phase);
return val;
endfunction : polar_to_complex
// Convert polar coordinates to an sc16 complex number. The phase should be
// in radians.
function sc16_t polar_to_sc16(real mag, real phase);
return complex_to_sc16(polar_to_complex(mag, phase));
endfunction : polar_to_sc16
//---------------------------------------------------------------------------
// Floating Point Complex Arithmetic
//---------------------------------------------------------------------------
// Add two complex numbers: x + y
function complex_t add(complex_t x, complex_t y);
complex_t val;
val.re = x.re + y.re;
val.im = x.im + y.im;
return val;
endfunction : add
// Subtract two complex numbers: x - y
function complex_t sub(complex_t x, complex_t y);
complex_t val;
val.re = x.re - y.re;
val.im = x.im - y.im;
return val;
endfunction : sub
// Multiply two complex numbers: x * y
function complex_t mul(complex_t x, complex_t y);
complex_t val;
val.re = x.re*y.re - x.im*y.im;
val.im = x.re*y.im + x.im*y.re;
return val;
endfunction : mul
// Divide two complex numbers: x / y
function complex_t div(complex_t x, complex_t y);
complex_t z;
z.re = (x.re*y.re + x.im*y.im) / (y.re*y.re + y.im*y.im);
z.im = (x.im*y.re + x.re*y.im) / (y.re*y.re + y.im*y.im);
return z;
endfunction : div
// Compute the exponential: e^x
function complex_t exp(complex_t x);
complex_t val;
// exp(a+jb) = exp(a)*exp(jb) = exp(a)*(cos(b) + j*sin(b))
val.re = $exp(x.re)*$cos(x.im);
val.im = $exp(x.re)*$sin(x.im);
return val;
endfunction : exp
// Compute the sine: sin(x)
function complex_t sin(complex_t x);
complex_t val;
val.re = $sin(x.re)*$cosh(x.im);
val.im = $cos(x.re)*$sinh(x.im);
return val;
endfunction : sin
// Compute the cosine: cos(x)
function complex_t cos(complex_t x);
complex_t val;
val.re = $cos(x.re)*$cosh(x.im);
val.im = -1.0*$sin(x.re)*$sinh(x.im);
return val;
endfunction : cos
// Compute the magnitude/modulus/absolute value: |x|
function real mag(complex_t x);
return $sqrt(x.re*x.re + x.im*x.im);
endfunction : mag
// Compute the phase/argument: arg(x)
function real arg(complex_t x);
return $atan2(x.im, x.re);
endfunction : arg
//---------------------------------------------------------------------------
// Fixed-Point Complex Arithmetic
//---------------------------------------------------------------------------
// Add two complex numbers: x + y
function sc16_t add_sc16(sc16_t x, sc16_t y);
return complex_to_sc16(add(sc16_to_complex(x), sc16_to_complex(y)));
endfunction : add_sc16
// Subtract two complex numbers: x - y
function sc16_t sub_sc16(sc16_t x, sc16_t y);
return complex_to_sc16(sub(sc16_to_complex(x), sc16_to_complex(y)));
endfunction : sub_sc16
// Multiply two complex numbers: x * y
function sc16_t mul_sc16(sc16_t x, sc16_t y);
return complex_to_sc16(mul(sc16_to_complex(x), sc16_to_complex(y)));
endfunction : mul_sc16
// Divide two complex numbers: x / y
function sc16_t div_sc16(sc16_t x, sc16_t y);
return complex_to_sc16(div(sc16_to_complex(x), sc16_to_complex(y)));
endfunction : div_sc16
// Compute the exponential: e^x
function sc16_t exp_sc16(sc16_t x);
return complex_to_sc16(exp(sc16_to_complex(x)));
endfunction : exp_sc16
// Compute the sine: sin(x)
function sc16_t sin_sc16(sc16_t x);
return complex_to_sc16(sin(sc16_to_complex(x)));
endfunction : sin_sc16
// compute the cosine: cos(x)
function sc16_t cos_sc16(sc16_t x);
return complex_to_sc16(cos(sc16_to_complex(x)));
endfunction : cos_sc16
// Compute the magnitude/modulus/absolute value: |x|
function s16_t mag_sc16(sc16_t x);
return real_to_s16(mag(sc16_to_complex(x)));
endfunction : mag_sc16
// Compute the phase/argument: arg(x)
function s16_t arg_sc16(sc16_t x);
return real_to_s16(arg(sc16_to_complex(x)));
endfunction : arg_sc16
endpackage : PkgComplex
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//
// Copyright 2021 Ettus Research, A National Instruments Brand
//
// SPDX-License-Identifier: LGPL-3.0-or-later
//
// Package: PkgMath
//
// Description:
//
// SystemVerilog supports many Math functions. This adds a few that it
// doesn't have built in, as well as useful mathematical constants.
//
// SystemVerilog has built-in support for the following:
//
// $clog2 $asin
// $ln $acos
// $log10 $atan
// $exp $atan2
// $sqrt $hypot
// $pow $sinh
// $floor $cosh
// $ceil $tanh
// $sin $asinh
// $cos $acosh
// $tan $atanh
//
package PkgMath;
//---------------------------------------------------------------------------
// Constants
//---------------------------------------------------------------------------
localparam real PI = 2*$acos(0.0);
localparam real TAU = 4*$acos(0.0);
localparam real PHI = (1 + $sqrt(5.0)) / 2.0;
localparam real E = $exp(1);
localparam byte BYTE_MAX = 8'sh7F;
localparam byte BYTE_MIN = 8'sh80;
localparam shortint SHORT_MAX = 16'sh7FFF;
localparam shortint SHORT_MIN = 16'sh8000;
localparam int INT_MAX = 32'sh7FFFFFFF;
localparam int INT_MIN = 32'sh80000000;
localparam longint LONG_MAX = 64'sh7FFFFFFFFFFFFFFF;
localparam longint LONG_MIN = 64'sh8000000000000000;
localparam byte unsigned UBYTE_MAX = 8'hFF;
localparam byte unsigned UBYTE_MIN = 8'h00;
localparam shortint unsigned USHORT_MAX = 16'hFFFF;
localparam shortint unsigned USHORT_MIN = 16'h0000;
localparam int unsigned UINT_MAX = 32'hFFFFFFFF;
localparam int unsigned UINT_MIN = 32'h00000000;
localparam longint unsigned ULONG_MAX = 64'hFFFFFFFFFFFFFFFF;
localparam longint unsigned ULONG_MIN = 64'h0000000000000000;
//---------------------------------------------------------------------------
// Functions (For real data types)
//---------------------------------------------------------------------------
// Return the absolute value
function automatic real abs(real num);
if (num < 0) return -1.0*num;
return num;
endfunction : abs
// Round a float to the nearest whole number, rounding away from zero for 0.5
// (same as C++ and default SystemVerilog behavior).
function automatic real round(real num);
if (num >= 0) begin
// Round toward +inf
if (num - $floor(num) < 0.5) return $floor(num);
return $ceil(num);
end else begin
// Round toward -inf
if (num - $floor(num) <= 0.5) return $floor(num);
return $ceil(num);
end
endfunction : round
// Round a float to the nearest value having bits to the right of the binary
// point. For example:
//
// 1.2265625 (0b1.0011101) --> 3 bits --> 1.25000 (0b1.0100000)
// 1.2265625 (0b1.0011101) --> 5 bits --> 1.21875 (0b1.0011100)
//
function automatic real round_bits(real num, int unsigned bits);
return round(num * 2.0**bits) / (2.0**bits);
endfunction : round_bits
// Return the sign of num as +1.0 or -1.0;
function automatic real sign(real num);
if (num < 0.0) return -1.0;
return 1.0;
endfunction : sign;
// Return the modulus (remainder) of a / b, with the sign of the numerator.
// This should match the C++ standard library std::fmod() behavior, as well
// as SystemVerilog % operator with integer values.
function automatic real fmod(real a, real b);
a = abs(a);
b = abs(b);
return sign(b) * (a - ($floor(a / b) * b));
endfunction : fmod
// Return the (remainder) of a / b, where the quotient is rounded to the
// nearest integer. This should approximate the C++ standard library
// std::remainder() behavior.
function automatic real remainder(real a, real b);
return a - round(a/b)*b;
endfunction : remainder
// Return the maximum of a and b.
function automatic real fmax(real a, real b);
if (a > b) return a;
return b;
endfunction : fmax
// Return the minimum of a and b.
function automatic real fmin(real a, real b);
if (a < b) return a;
return b;
endfunction : fmin
//---------------------------------------------------------------------------
// Template Functions (For any data type)
//---------------------------------------------------------------------------
class Math #(type T);
static function T abs(T num);
if (num < 0) return -num;
return num;
endfunction : abs
static function T sign(T num);
if (num < 0) return -1;
return 1;
endfunction : sign
static function T max(T a, T b);
if (a > b) return a;
else return b;
endfunction : max
static function T min(T a, T b);
if (a < b) return a;
else return b;
endfunction : min
endclass : Math
endpackage : PkgMath
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//
// Copyright 2021 Ettus Research, A National Instruments Brand
//
// SPDX-License-Identifier: LGPL-3.0-or-later
//
// Package: PkgRandom
//
// Description:
//
// SystemVerilog has great randomization support, but some features require a
// more expensive license or aren't supported by all tools. This package
// tries to fill that gap by providing some useful randomization functions
// beyond what's supported by standard Verilog.
//
package PkgRandom;
import PkgMath::*;
//---------------------------------------------------------------------------
// Functions
//---------------------------------------------------------------------------
// Return a real value in the range [0,max), where max is 1.0 by default.
function automatic real frand(real max = 1.0);
bit [63:0] real_bits;
real num;
// Build a double-precision floating point value per IEEE-754 standard,
// which SystemVerilog follows.
// Positive, with exponent 0
real_bits[63:52] = 12'h3FF;
// Mantissa in the range [1.0, 2.0). The leading 1 in the mantissa is
// implied by the floating point format.
real_bits[31: 0] = $urandom();
real_bits[51:32] = $urandom();
// Compensate for the implied leading 1 in the mantissa by subtracting 1.
num = $bitstoreal(real_bits) - 1.0;
// Scale the result to return a value in the desired range.
return num * max;
endfunction : frand
// Return a real value in the range [a,b), [b,a), or [0,a) depending on
// whether a or b is larger and whether b is provided. This matches the
// behavior of $urandom_range().
//
// frand_range(1.0, 2.0) -> Random value in the range [1,2)
// frand_range(2.0, 1.0) -> Random value in the range [1,2)
// frand_range(1.0) -> Random value in the range [0,1)
//
function automatic real frand_range(real a = 1.0, real b = 0.0);
if (a > b) return b + frand(a - b);
if (b > a) return a + frand(b - a);
return a;
endfunction : frand_range
// Return a real value with a normal distribution, having the mean value mu
// and standard deviation sigma.
function automatic real frandn(real sigma = 1.0, real mu = 0.0);
// Use the Box-Muller transform to convert uniform random variables to a
// Gaussian one.
return sigma*$sqrt(-2.0*$ln(frand())) * $cos(TAU*frand()) + mu;
endfunction : frandn
//---------------------------------------------------------------------------
// Template Functions
//---------------------------------------------------------------------------
class Rand #(WIDTH = 64);
// These are static class functions. They can be called directly, as in:
//
// Rand#(N)::rand_bit()
//
// Or, you can declare an object reference, as in:
//
// Rand #(N) rand;
// rand.rand_bit();
typedef bit [WIDTH-1:0] unsigned_t;
typedef bit signed [WIDTH-1:0] signed_t;
// Returns a WIDTH-bit random bit packed array.
static function unsigned_t rand_bit();
unsigned_t result;
int num_rand32 = (WIDTH + 31) / 32;
for (int i = 0; i < num_rand32; i++) begin
result = {result, $urandom()};
end
return result;
endfunction : rand_bit
// Returns a WIDTH-bit random number in the UNSIGNED range [a,b], [b,a], or
// [0,a] depending on whether a or b is greater and if b is provided. This
// is equivalent to $urandom_range() but works with any length.
static function bit [WIDTH-1:0] rand_bit_range(
unsigned_t a = {WIDTH{1'b1}},
unsigned_t b = 0
);
unsigned_t num;
int num_bits;
if (a > b) begin
// Swap a and b
unsigned_t temp;
temp = a;
a = b;
b = temp;
end
num_bits = $clog2(b - a + unsigned_t'{1});
do begin
num = a + (rand_bit() & ((unsigned_t'{1} << num_bits) - 1));
end while (num > b);
return num;
endfunction : rand_bit_range
// Returns a random number in the given SIGNED range. Behavior is the same
// as rand_bit_range(), bunsigned_t treats the range values as SIGNED numbers.
static function signed_t rand_sbit_range(
signed_t a = {1'b0, {WIDTH{1'b1}}},
signed_t b = 0
);
if (a > b) return b + $signed(rand_bit_range(0, a-b));
if (b > a) return a + $signed(rand_bit_range(0, b-a));
return a;
endfunction : rand_sbit_range
// Rand#(WIDTH)::rand_logic() returns a WIDTH-bit random logic packed
// array. Each bit will be 0 or 1 with equal probability (not X or Z).
static function logic [WIDTH-1:0] rand_logic();
return rand_bit();
endfunction : rand_logic
endclass : Rand
endpackage : PkgRandom