#!/micropython
# vim: fileencoding=utf-8: ts=4: sw=4: expandtab:
from sys import implementation as impl
from machine import freq as cpufreq
from time import ticks_us,ticks_diff

KILO    = const(1_000)
MEGA    = const(1_000_000)
CPUFREQ = const(240*MEGA)
# SIZE    = const(116*KILO)       # max. for RP2040
SIZE    = const(242*KILO)       # max. for RP2350
# SIZE    = const(900*KILO)       # ~ for an ESP with 2MiB PSRAM


@micropython.viper
def memcpyB(src: ptr8, dest: ptr8, size:int):
    idx: int = size
    while (idx:=idx-1) >= 0:
        dest[idx] = src[idx]

@micropython.viper
def memcpyHW(src: ptr16, dest: ptr16, size:int):
    idx: int = size//2
    while (idx:=idx-1) >= 0:
        dest[idx] = src[idx]

@micropython.viper
def memcpyW(src: ptr32, dest: ptr32, size:int):
    idx: int = size//4
    while (idx:=idx-1) >= 0:
        dest[idx] = src[idx]

#   @micropython.asm_thumb
#   def memcpyAsm(r0,r1,r2):            # src: ptr32, dest: ptr32, size:int):
#       sub     (r2,r2,4)
#       label   (loop)
#       data    (2,0b0101100010000011)  #2    ldr     (r3, [r0,r2])
#       data    (2,0b0101000010001011)  #2    str     (r3, [r1,r2])
#       sub     (r2,r2,4)               #1
#       bpl     (loop)                  #2/1

def test():
    normfreq = cpufreq()
    cpufreq(CPUFREQ)
    t0 = ticks_us()
    ba1 = bytearray(SIZE)
    ba2 = bytearray(SIZE)
    t1 = ticks_us()
    memcpyB(ba1, ba2, SIZE)
    t2 = ticks_us()
    memcpyHW(ba1, ba2, SIZE)
    t3 = ticks_us()
    memcpyW(ba1, ba2, SIZE)
    t4 = ticks_us()
    # memcpyAsm(ba1, ba2, SIZE)
    t5 = ticks_us()
    td2 = ticks_diff(t2,t1)
    td3 = ticks_diff(t3,t2)
    td4 = ticks_diff(t4,t3)
    # td5 = ticks_diff(t5,t4)

    print(f'CPU: {impl[2]} @ {cpufreq()/MEGA} MHz')     # CPU: Raspberry Pi Pico2 with RP2350 @ 240.0 MHz
    print(f'alloc:  {ticks_diff(t1,t0):6} µs')          # alloc:    2286 µs
    print(f'BYTE:   {td2:6} µs   {SIZE/td2:6.1f} MB/s') # BYTE:    25019 µs      9.6 MB/s
    print(f'HALF:   {td3:6} µs   {SIZE/td3:6.1f} MB/s') # HALF:    13508 µs     17.8 MB/s
    print(f'WORD:   {td4:6} µs   {SIZE/td4:6.1f} MB/s') # WORD:     6758 µs     35.5 MB/s
    # print(f'WORDasm:{td5:6} µs   {SIZE/td5:6.1f} MB/s') # WORDasm:  1772 µs    187.8 MB/s
    cpufreq(normfreq)

test()