#v1.19.1 (2022-06-18) .uf2
from random import randint
from time import ticks_us, ticks_diff
import array
from micropython import const

SEED = const(0)

control=array.array('i',(999999,240))

@micropython.asm_thumb
def rand_asm2(r0):
  ldr(r1,[r0,0])      # seed
  ldr(r4,[r0,4])      # max random
  label(RANDOM_LOOP)
  add(r1,13)
  mov(r2,r1)
  mov(r3,9)
  ror(r2,r3)
  eor(r1,r2)
  asr(r2,r1,24)
  add(r2,127)
  cmp(r2,r4)
  bgt(RANDOM_LOOP)
  label(EXIT)
  str(r1,[r0,0])
  mov(r0,r2)

@micropython.asm_thumb
def rand_asm(r0,r1):
    mov(r4,r1)
    label(RANDOM)         # uses r1-r5, input=r4, output r2
    ldr(r1,[r0,SEED])     # seed
    mov(r5,33)              
    mov(r2,r4)            # r4 = max random number
    label(HIGHBITS)       # counts bits required 
    sub(r5,r5,1)          
    lsl(r2,r2,1)
    bcc(HIGHBITS)         # r5 = max bits
    label(RANDOM_LOOP)
    add(r1,13)            # scramble seed
    mov(r2,r1)            #
    mov(r3,9)
    ror(r2,r3)
    eor(r1,r2)            # end scramble
    mov(r2,r1)            # r2 = random 32 bit number
    str(r1,[r0,SEED])
    mov(r3,32)
    sub(r3,r3,r5)
    asr(r2,r3)            # scale down to max random
    mov(r3,1)
    sub(r5,1)
    lsl(r3,r5)            # shift 17 bits to get offset
    add(r2,r2,r3)         # add offset for positive
    #bmi(RANDOM_LOOP)     # sometimes get negative?
    cmp(r2,r4)            # get another if too high
    bgt(RANDOM_LOOP)
    mov(r0,r2)

rand = 1
m=0
odd = 0
tot_array = array.array('i', 0 for _ in range(101))
gticks = ticks_us()
for i in range(1000):
  #rand = 1
  #rand=randint(0,10)
  #rand=rand_asm(control,10)
  tot_array[rand] += 1
  if not rand % 2:
    odd += 1
  #b=7
  #x=((1<<b)+(seed>>(31-b) )) 
  #print(x)
  if rand>m:
    m=rand
  #print(rand)
#print('Odd numbers',odd)
diff = ticks_diff(ticks_us(),gticks)
print()
print(diff/1000)

print()
#print(tot_array)