simonbyrne

function sincos(x)
    psin = Cdouble[0]; pcos = Cdouble[0]
    ccall(:sincos, Void, (Cdouble, Ptr{Cdouble}, Ptr{Cdouble}), x, psin, pcos)
    psin[1], pcos[1]
end

function foo(X)
    ta = 0.0
    tb = 0.0
    for x in X

simonbyrne

function getmxcsr()
    Base.llvmcall("""%ptr = alloca i32
                  call void @llvm.x86.sse.stmxcsr(i32 * %ptr)
                  %curval = load i32 * %ptr
                  ret i32 %curval""", UInt32, ())
end

function setmxcsr(u::UInt32)
    Base.llvmcall("""%ptr = alloca i32
                  store i32 %0, i32 * %ptr

simonbyrne

function rint_llvm(x::Float64)
    Base.llvmcall("""%x = call double @llvm.rint.f64(double %0)
                  ret double %x""",Float64,(Float64,),x)
end
function trunc_llvm(x::Float64)
    Base.llvmcall("""%x = call double @llvm.trunc.f64(double %0)
                  ret double %x""",Float64,(Float64,),x)
end

# warm up llvmcall: ignore errors

simonbyrne

simonbyrne

# use floating point AND instructions (andps/andpd)
# https://github.com/JuliaLang/julia/issues/9868
function and_float(x::Float64,y::Float64)
       Base.llvmcall("""%av = insertelement<2 x double> undef, double %0, i32 0
         %bv = insertelement<2 x double> undef, double %1, i32 0
         %ai = bitcast <2 x double> %av to <2 x i64>
         %bi = bitcast <2 x double> %bv to <2 x i64>
         %and.i = and <2 x i64> %ai, %bi
         %cf = bitcast <2 x i64> %and.i to <2 x double>
         %cfe = extractelement<2 x double> %cf, i32 0

simonbyrne

#include <stdio.h>
#include <math.h>

int main() {
  volatile double a = 0.1;
  volatile double x = a + 0.2;
  printf("%.20f\n", x);
  volatile double y = fma(a, 1.0, 0.0);
  printf("%.20f\n", y);
  volatile double z = y + 0.2;

simonbyrne

include <stdio.h>                                                                                       
#include <stdlib.h>
#include <math.h>

static double fct (double a)
{
  double x = fma(a,a,-a);
  return 1.0 - x;
}

simonbyrne

function sincos(x::Float64)
    s = Ref{Float64}()
    c = Ref{Float64}()
    ccall((:sincos,Base.Math.libm),Void,(Float64,Ref{Float64},Ref{Float64}),x,s,c)
    return s.x, c.x
end
    

function test_sep(X)
    t = 0.0

simonbyrne

simonbyrne

function winenvs(var)
# Win: ansi
len = ccall(:GetEnvironmentVariableA,stdcall,Uint32,(Ptr{Uint8},Ptr{Uint8},Uint32),var,C_NULL,0)
if len > 0
    val=zeros(Uint8,len)
    ccall(:GetEnvironmentVariableA,stdcall,Uint32,(Ptr{Uint8},Ptr{Uint8},Uint32),var,val,len)
    win_a = bytestring(val)
else
    win_a = ""