/** * Copyright (c) 2020 Raspberry Pi (Trading) Ltd. * * SPDX-License-Identifier: BSD-3-Clause */ #include <stdio.h> #include "pico/stdlib.h" #include "hardware/divider.h" /// \tag::hello_divider[] int main() { stdio_init_all(); printf("Hello, divider!\n"); // This is the basic hardware divider function int32_t dividend = 123456; int32_t divisor = -321; divmod_result_t result = hw_divider_divmod_s32(dividend, divisor); printf("%d/%d = %d remainder %d\n", dividend, divisor, to_quotient_s32(result), to_remainder_s32(result)); // Is it right? printf("Working backwards! Result %d should equal %d!\n\n", to_quotient_s32(result) * divisor + to_remainder_s32(result), dividend); // This is the recommended unsigned fast divider for general use. int32_t udividend = 123456; int32_t udivisor = 321; divmod_result_t uresult = hw_divider_divmod_u32(udividend, udivisor); printf("%d/%d = %d remainder %d\n", udividend, udivisor, to_quotient_u32(uresult), to_remainder_u32(uresult)); // Is it right? printf("Working backwards! Result %d should equal %d!\n\n", to_quotient_u32(result) * divisor + to_remainder_u32(result), dividend); // You can also do divides asynchronously. Divides will be complete after 8 cycles. hw_divider_divmod_s32_start(dividend, divisor); // Do something for 8 cycles! // In this example, our results function will wait for completion. // Use hw_divider_result_nowait() if you don't want to wait, but are sure you have delayed at least 8 cycles result = hw_divider_result_wait(); printf("Async result %d/%d = %d remainder %d\n", dividend, divisor, to_quotient_s32(result), to_remainder_s32(result)); // For a really fast divide, you can use the inlined versions... the / involves a function call as / always does // when using the ARM AEABI, so if you really want the best performance use the inlined versions. // Note that the / operator function DOES use the hardware divider by default, although you can change // that behavior by calling pico_set_divider_implementation in the cmake build for your target. printf("%d / %d = (by operator %d) (inlined %d)\n", dividend, divisor, dividend / divisor, hw_divider_s32_quotient_inlined(dividend, divisor)); // Note however you must manually save/restore the divider state if you call the inlined methods from within an IRQ // handler. hw_divider_state_t state; hw_divider_divmod_s32_start(dividend, divisor); hw_divider_save_state(&state); hw_divider_divmod_s32_start(123, 7); printf("inner %d / %d = %d\n", 123, 7, hw_divider_s32_quotient_wait()); hw_divider_restore_state(&state); int32_t tmp = hw_divider_s32_quotient_wait(); printf("outer divide %d / %d = %d\n", dividend, divisor, tmp); return 0; } /// \end::hello_divider[]

This firmware image was imported from the pico-examples repository. 


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