e_prime.nim

proc e_get_coreid(): cint {.header: "e_lib.h"}

proc is_prime(number: uint32): bool =
  for i in 2..number div 2:
    if number mod i == 0:
      return false
  return true

var
  count = cast[ptr uint32](0x7000)
  num = cast[ptr uint32](0x7008)
  primes = cast[ptr uint32](0x7010)
  max_tests = cast[ptr uint32](0x7020)

proc main() = 
  let
    core_id = int(e_get_coreid())
    row = (coreid shr 6) and 0x3f
    col = coreid and 0x3f

  # Assign the starting value for each core (3,5,7,..33)
  # Each core starts with a unique odd number (2 is the only even prime number)
  var number: uint32 = uint32(2 + ((2*row*4) + (2*col+1)))
  
  # Initialize this core iteration count for stats
  count[] = 0
  
  # Initialize the number of found primes counter
  primes[] = 0
  
  while count[] < max_tests[]:
    if is_prime(number):
      primes[] = primes[] + 1
  
    # Skip to the next odd number for this core to test, assuming total of 16 cores
    # Core (0,0) started with 3 on the first iteration, and next test 35
    # Core (0,1) started with 5 on the first iteration, and next test 37
    # etc
    number += (2*16);

    num[] = number;
  
    count[] = count[] + 1

main()