'Example of matrix layout mapped to an array of 4x4 cells
  '
  '  0 4 8 C
  '  1 5 9 D
  '  2 6 A E
  '  3 7 B F
  '

  % MatrixType double

  sub MatrixMul(MatrixType *A,*B,*C, sys n)
  '========================================
  '
  '
  #if leftmatch matrixtype single
    % OneStep 4
    % mtype single
  #endif
  '
  #if leftmatch matrixtype double
    % OneStep 8
    % mtype double
  #endif

  sys pa=@A, pb=@B, pc=@C
  sys ColStep=OneStep*n

  mov ecx,pa
  mov edx,pb
  mov eax,pc

  mov esi,n
  (
  call column : dec esi : jg repeat
  )
  exit sub

  column:
  '======

  mov edi,n
  (
  call cell : dec edi : jg repeat
  )
  add edx,ColStep
  sub ecx,ColStep
  ret

  cell: ' row A * column B
  '=======================

  'matrix data is stored ascending vertically then horizontally
  'thus rows are minor, columns are major
  '
  push  ecx
  push  edx
  push  eax
  mov   eax,4
  fldz
  (
  fld   mtype [ecx]
  fmul  mtype [edx]
  faddp st1
  add   ecx,ColStep 'next column of matrix A
  add   edx,OneStep 'next row of matrix B
  dec eax
  jnz repeat
  )
  pop eax
  fstp mtype [eax] 'assign to next row of matrix C
  '
  pop edx
  pop ecx
  add   eax,OneStep 'next cell in column of matrix C (columns then rows)
  add   ecx,OneStep 'next row of matrix A
  ret
  '
  end sub


  function ShowMatrix(MatrixType*A,sys n) as string
  '================================================
    string cr=chr(13)+chr(10), tab=chr(9)
    function="MATRIX " n "x" n cr cr
    sys i,j,m
    '
    for i=1 to n
      m=0
      for j=1 to n
        function+=str( A[m+i] ) tab
        m+=n
      next
      function+=cr
    next
  end function

  'TEST
  '====

  % n 4
  MatrixType A[n*n],B[n*n],C[n*n]


  'reading vertically (minor) then left to right (major)

  A <= 4,0,0,1, 0,4,0,0, 0,0,4,0, 0,0,0,4

  B <= 2,0,0,2, 0,2,0,0, 0,0,2,0, 0,0,0,2


  MatrixMul A,B,C,n

  Print ShowMatrix C,n