// Test main
#90 = Time_Tick                   // seed for random number generator
#99 = 20                          // number of items in the array

IT("Before:") IN
for (#100 = 0; #100 < #99; #100++) {
    #@100 = #100
    Num_Ins(#@100, LEFT+NOCR) IT(" ")
}
IN

Call("SHUFFLE_NUMBERS")

IT("After:") IN
for (#100 = 0; #100 < #99; #100++) {
    Num_Ins(#@100, LEFT+NOCR) IT(" ")
}
IN
Return

//--------------------------------------------------------------
// Shuffle numeric registers #0 to #nn
//  #99 = number of registers to shuffle (nn-1)
//
:SHUFFLE_NUMBERS:
for (#91 = #99-1; #91 > 0; #91--) {
    Call("RANDOM")
    #101 = Return_Value
    #102 = #@101; #@101 = #@91; #@91 = #102
}
Return

//--------------------------------------------------------------
// Generate random numbers in range 0 <= Return_Value < #91
//  #90 = Seed    (0 to 0x7fffffff)
//  #91 = Scaling (0 to 0x10000)
//
:RANDOM:
#92 = 0x7fffffff / 48271
#93 = 0x7fffffff % 48271
#90 = (48271 * (#90 % #92) - #93 * (#90 / #92)) & 0x7fffffff
Return ((#90 & 0xffff) * #91 / 0x10000)