From bafa9d95453387814ef25e6b6256ba8db2df612f Mon Sep 17 00:00:00 2001 From: Martin Braun Date: Thu, 23 Jan 2020 16:10:22 -0800 Subject: Merge FPGA repository back into UHD repository MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The FPGA codebase was removed from the UHD repository in 2014 to reduce the size of the repository. However, over the last half-decade, the split between the repositories has proven more burdensome than it has been helpful. By merging the FPGA code back, it will be possible to create atomic commits that touch both FPGA and UHD codebases. Continuous integration testing is also simplified by merging the repositories, because it was previously difficult to automatically derive the correct UHD branch when testing a feature branch on the FPGA repository. This commit also updates the license files and paths therein. We are therefore merging the repositories again. Future development for FPGA code will happen in the same repository as the UHD host code and MPM code. == Original Codebase and Rebasing == The original FPGA repository will be hosted for the foreseeable future at its original local location: https://github.com/EttusResearch/fpga/ It can be used for bisecting, reference, and a more detailed history. The final commit from said repository to be merged here is 05003794e2da61cabf64dd278c45685a7abad7ec. This commit is tagged as v4.0.0.0-pre-uhd-merge. If you have changes in the FPGA repository that you want to rebase onto the UHD repository, simply run the following commands: - Create a directory to store patches (this should be an empty directory): mkdir ~/patches - Now make sure that your FPGA codebase is based on the same state as the code that was merged: cd src/fpga # Or wherever your FPGA code is stored git rebase v4.0.0.0-pre-uhd-merge Note: The rebase command may look slightly different depending on what exactly you're trying to rebase. - Create a patch set for your changes versus v4.0.0.0-pre-uhd-merge: git format-patch v4.0.0.0-pre-uhd-merge -o ~/patches Note: Make sure that only patches are stored in your output directory. It should otherwise be empty. Make sure that you picked the correct range of commits, and only commits you wanted to rebase were exported as patch files. - Go to the UHD repository and apply the patches: cd src/uhd # Or wherever your UHD repository is stored git am --directory fpga ~/patches/* rm -rf ~/patches # This is for cleanup == Contributors == The following people have contributed mainly to these files (this list is not complete): Co-authored-by: Alex Williams Co-authored-by: Andrej Rode Co-authored-by: Ashish Chaudhari Co-authored-by: Ben Hilburn Co-authored-by: Ciro Nishiguchi Co-authored-by: Daniel Jepson Co-authored-by: Derek Kozel Co-authored-by: EJ Kreinar Co-authored-by: Humberto Jimenez Co-authored-by: Ian Buckley Co-authored-by: Jörg Hofrichter Co-authored-by: Jon Kiser Co-authored-by: Josh Blum Co-authored-by: Jonathon Pendlum Co-authored-by: Martin Braun Co-authored-by: Matt Ettus Co-authored-by: Michael West Co-authored-by: Moritz Fischer Co-authored-by: Nick Foster Co-authored-by: Nicolas Cuervo Co-authored-by: Paul Butler Co-authored-by: Paul David Co-authored-by: Ryan Marlow Co-authored-by: Sugandha Gupta Co-authored-by: Sylvain Munaut Co-authored-by: Trung Tran Co-authored-by: Vidush Vishwanath Co-authored-by: Wade Fife --- fpga/usrp3/sim/general/sim_math.vh | 276 +++++++++++++++++++++++++++++++++++++ 1 file changed, 276 insertions(+) create mode 100644 fpga/usrp3/sim/general/sim_math.vh (limited to 'fpga/usrp3/sim/general/sim_math.vh') diff --git a/fpga/usrp3/sim/general/sim_math.vh b/fpga/usrp3/sim/general/sim_math.vh new file mode 100644 index 000000000..a08870740 --- /dev/null +++ b/fpga/usrp3/sim/general/sim_math.vh @@ -0,0 +1,276 @@ +// All code take from the HDLCon paper: +// "Verilog Transcendental Functions for Numerical Testbenches" +// +// Authored by: +// Mark G. Arnold marnold@co.umist.ac.uk, +// Colin Walter c.walter@co.umist.ac.uk +// Freddy Engineer freddy.engineer@xilinx.com +// + + + +// The sine function is approximated with a polynomial which works +// for -π/2 < x < π/2. (This polynomial, by itself, was used as a +// Verilog example in [2]; unfortunately there was a typo with the +// coefficients. The correct coefficients together with an error +// analysis are given in [3].) For arguments outside of -π/2 < x < π/2, +// the identities sin(x) = -sin(-x) and sin(x) = -sin(x-π) allow the +// argument to be shifted to be within this range. The latter identity +// can be applied repeatedly. Doing so could cause inaccuracies for +// very large arguments, but in practice the errors are acceptable +// if the Verilog simulator uses double-precision floating point. + +function real sin; + input x; + real x; + real x1,y,y2,y3,y5,y7,sum,sign; + begin + sign = 1.0; + x1 = x; + if (x1<0) + begin + x1 = -x1; + sign = -1.0; + end + while (x1 > 3.14159265/2.0) + begin + x1 = x1 - 3.14159265; + sign = -1.0*sign; + end + y = x1*2/3.14159265; + y2 = y*y; + y3 = y*y2; + y5 = y3*y2; + y7 = y5*y2; + sum = 1.570794*y - 0.645962*y3 + + 0.079692*y5 - 0.004681712*y7; + sin = sign*sum; + end +endfunction + +// The cosine and tangent are computed from the sine: +function real cos; + input x; + real x; + begin + cos = sin(x + 3.14159265/2.0); + end +endfunction + + +function real tan; + input x; + real x; + begin + tan = sin(x)/cos(x); + end +endfunction + +// The base-two exponential (antilogarithm) function, 2x, is computed by +// examining the bits of the argument, and for those bits of the argument +// that are 1, multiplying the result by the corresponding power of a base +// very close to one. For example, if there were only two bits after +// the radix point, the base would be the fourth root of two, 1.1892. +// This number is squared on each iteration: 1.4142, 2.0, 4.0, 16.0. +// So, if x is 101.112, the function computes 25.75 as 1.1892*1.4142*2.0*16.0 = 53.81. +// In general, for k bits of precision, the base would be the 2k root of two. +// Since we need about 23 bits of accuracy for our function, the base we use +// is the 223 root of two, 1.000000082629586. This constant poses a problem +// to some Verilog parsers, so we construct it in two parts. The following +// function computes the appropriate root of two by repeatedly squaring this constant: + +function real rootof2; + input n; + integer n; + real power; + integer i; + + begin + power = 0.82629586; + power = power / 10000000.0; + power = power + 1.0; + i = -23; + + if (n >= 1) + begin + power = 2.0; + i = 0; + end + + for (i=i; i< n; i=i+1) + begin + power = power * power; + end + rootof2 = power; + end +endfunction // if + +// This function is used for computing both antilogarithms and logarithms. +// This routine is never called with n less than -23, thus no validity check +// need be performed. When n>0, the exponentiation begins with 2.0 in order to +// improve accuracy. +// For computing the antilogarithm, we make use of the identity ex = 2x/ln(2), +// and then proceed as in the example above. The constant 1/ln(2) = 1.44269504. +// Here is the natural exponential function: + +function real exp; + input x; + real x; + real x1,power,prod; + integer i; + begin + x1 = fabs(x)*1.44269504; + if (x1 > 255.0) + begin + exp = 0.0; + if (x>0.0) + begin + $display("exp illegal argument:",x); + $stop; + end + end + else + begin + prod = 1.0; + power = 128.0; + for (i=7; i>=-23; i=i-1) + begin + if (x1 > power) + begin + prod = prod * rootof2(i); + x1 = x1 - power; + end + power = power / 2.0; + end + if (x < 0) + exp = 1.0/prod; + else + exp = prod; + end + end +endfunction // fabs + +// The function prints an error message if the argument is too large +// (greater than about 180). All error messages in this package are +// followed by $stop to allow the designer to use the debugging +// features of Verilog to determine the cause of the error, and +// possibly to resume the simulation. An argument of less than +// about –180 simply returns zero with no error. The main loop +// assumes a positive argument. A negative argument is computed as 1/e-x. +// The logarithm function prints an error message for arguments less +// than or equal to zero because the real-valued logarithm is not +// defined for such arguments. The loop here requires an argument +// greater than or equal to one. For arguments between zero and one, +// this code uses the identity ln(1/x) = -ln(x). + +function real log; + input x; + real x; + real re,log2; + integer i; + begin + if (x <= 0.0) + begin + $display("log illegal argument:",x); + $stop; + log = 0; + end + else + begin + if (x<1.0) + re = 1.0/x; + else + re = x; + log2 = 0.0; + for (i=7; i>=-23; i=i-1) + begin + if (re > rootof2(i)) + begin + re = re/rootof2(i); + log2 = 2.0*log2 + 1.0; + end + else + log2 = log2*2; + end + if (x < 1.0) + log = -log2/12102203.16; + else + log = log2/12102203.16; + end + end +endfunction + +// The code only divides re by rootof2(i) when the re is larger +// (so that the quotient will be greater than 1.0). Each time +// such a division occurs, a bit that is 1 is recorded in the +// whole number result (multiply by 2 and add 1). Otherwise, +// a zero is recorded (multiply by 2). At the end of the loop, +// log2 will contain 223 log2|x|. We divide by 223 and use the +// identity ln(x) = log2(x)/log2(e). The constant 12102203.16 is 223 log2(e). +// The log(x) and exp(x)functions are used to implement the pow(x,y) and sqrt(x) functions: + +function real pow; + input x,y; + real x,y; + begin + if (x<0.0) + begin + $display("pow illegal argument:",x); + $stop; + end + pow = exp(y*log(x)); + end +endfunction + +function real sqrt; + input x; + real x; + begin + if (x<0.0) + begin + $display("sqrt illegal argument:",x); + $stop; + end + sqrt = exp(0.5*log(x)); + end +endfunction + +// The arctangent [3,7] is computed as a continued fraction, +// using the identities tan-1(x) = -tan-1(-x) and tan-1(x) = π/2 - tan-1(1/x) +// to reduce the range to 0 < x < 1: + +function real atan; + input x; + real x; + real x1,x2,sign,bias; + real d3,s3; + begin + sign = 1.0; + bias = 0.0; + x1 = x; + if (x1 < 0.0) + begin + x1 = -x1; + sign = -1.0; + end + if (x1 > 1.0) + begin + x1 = 1.0/x1; + bias = sign*3.14159265/2.0; + sign = -1.0*sign; + end + x2 = x1*x1; + d3 = x2 + 1.44863154; + d3 = 0.26476862 / d3; + s3 = x2 + 3.3163354; + d3 = s3 - d3; + d3 = 7.10676 / d3; + s3 = 6.762139 + x2; + d3 = s3 - d3; + d3 = 3.7092563 / d3; + d3 = d3 + 0.17465544; + atan = sign*x1*d3+bias; + end +endfunction + +// The other functions (asin(x) and acos(x)) are computed from the arctangent. -- cgit v1.2.3