Datasheet

Ê6 ;
Ê7 ; This program uses the two's complement identity x + y == ~(~x - y)
Ê8
Ê9 pull
10 mov x, ~osr
11 pull
12 mov y, osr
13 jmp test ; this loop is equivalent to the following C code:
14 incr: ; while (y--)
15 jmp x-- test ; x--;
16 test: ; This has the effect of subtracting y from x, eventually.
17 jmp y-- incr
18 mov isr, ~x
19 push
A full 32-bit addition takes only around one minute at 125 MHz. The program pulls two numbers from the TX FIFO and
pushes their sum to the RX FIFO, which is perfect for use either with the system DMA, or directly by the processor:
Pico Examples: https://github.com/raspberrypi/pico-examples/tree/master/pio/addition/addition.c Lines 1 - 35
Ê1 /**
Ê2 * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
Ê3 *
Ê4 * SPDX-License-Identifier: BSD-3-Clause
Ê5 */
Ê6
Ê7 #include <stdlib.h>
Ê8 #include <stdio.h>
Ê9
10 #include "pico/stdlib.h"
11 #include "hardware/pio.h"
12 #include "addition.pio.h"
13
14 // Pop quiz: how many additions does the processor do when calling this function
15 uint32_t do_addition(PIO pio, uint sm, uint32_t a, uint32_t b) {
16 pio_sm_put_blocking(pio, sm, a);
17 pio_sm_put_blocking(pio, sm, b);
18 return pio_sm_get_blocking(pio, sm);
19 }
20
21 int main() {
22 stdio_init_all();
23
24 PIO pio = pio0;
25 uint sm = 0;
26 uint offset = pio_add_program(pio, &addition_program);
27 addition_program_init(pio, sm, offset);
28
29 printf("Doing some random additions:\n");
30 for (int i = 0; i < 10; ++i) {
31 uint a = rand() % 100;
32 uint b = rand() % 100;
33 printf("%u + %u = %u\n", a, b, do_addition(pio, sm, a, b));
34 }
35 }
RP2040 Datasheet
3.6. Examples 386