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style: enforce coding standard — headers, @brief on #define, Doxygen on statics, remove _ prefix, max 8 lines per function

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Kevin Thomas
2026-04-16 22:44:43 -04:00
parent 0833c32c94
commit 433263eac0
309 changed files with 10464 additions and 6668 deletions
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0x0008_unitialized-variables-d/0x0008_unitialized-variables-d.c
+105 -31
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@@ -1,23 +1,70 @@
/**
* @file 0x0008_unitialized-variables-d.c
* @brief Blink LED using pico_default_asm_volatile coprocessor instructions
* @author Kevin Thomas
* @date 2025
*
* MIT License
*
* Copyright (c) 2025 Kevin Thomas
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* -----------------------------------------------------------------------------
*
* Blinks an LED on GPIO16 using pico_default_asm_volatile to emit mcrr
* coprocessor instructions for GPIO output enable and data, plus inline
* assembly for pad configuration (hw_write_masked, IO_BANK0 FUNCSEL,
* hw_clear_bits equivalents).
*
* Wiring:
* GPIO16 -> LED anode (with current-limiting resistor to GND)
*/
#include <stdio.h>
#include "pico/stdlib.h"
#define LED_PIN 16
/** @brief GPIO pin number for the LED */
#define LED_PIN 16
int main(void)
{
// gpio_init(LED_PIN);
/// gpio_set_dir(LED_PIN, GPIO_IN);
//// gpioc_bit_oe_put(LED_PIN, GPIO_OUT);
/**
* @brief Enable output and set initial coprocessor OE/OUT via mcrr
*
* @details Issues two mcrr p0 instructions: one to enable output direction,
* one to set the initial output state.
*
* @retval None
*/
static void asm_set_oe_and_out(void) {
pico_default_asm_volatile ("mcrr p0, #4, %0, %1, c4" : : "r" (LED_PIN), "r" (GPIO_OUT));
/// gpio_put(LED_PIN, 0);
//// gpioc_bit_out_put(LED_PIN, 0);
pico_default_asm_volatile ("mcrr p0, #4, %0, %1, c4" : : "r" (LED_PIN), "r" (GPIO_OUT));
/// gpio_set_function(LED_PIN, GPIO_FUNC_SIO);
//// hw_write_masked(&pads_bank0_hw->io[LED_PIN],
//// PADS_BANK0_GPIO0_IE_BITS,
//// PADS_BANK0_GPIO0_IE_BITS | PADS_BANK0_GPIO0_OD_BITS
//// );
//// hw_xor_bits(addr, (*addr ^ values) & write_mask);
}
/**
* @brief Configure PADS_BANK0 IE/OD bits via inline assembly hw_xor_bits
*
* @details Performs a read-modify-write on the pad register to set IE
* and clear OD, replicating hw_write_masked behavior.
*
* @retval None
*/
static void asm_configure_pad(void) {
pico_default_asm_volatile (
"ldr r2, [%0]\n" // load current pad register
"eor r2, r2, %1\n" // xor with IE bit
@@ -30,8 +77,17 @@ int main(void)
"r" (PADS_BANK0_GPIO0_IE_BITS | PADS_BANK0_GPIO0_OD_BITS)
: "r2", "memory"
);
}
/// io_bank0_hw->io[LED_PIN].ctrl = GPIO_FUNC_SIO << IO_BANK0_GPIO0_CTRL_FUNCSEL_LSB;
/**
* @brief Set IO_BANK0 FUNCSEL to SIO via inline assembly store
*
* @details Writes the SIO function select value directly to the
* IO_BANK0 GPIO control register.
*
* @retval None
*/
static void asm_set_funcsel(void) {
pico_default_asm_volatile (
"str %1, [%0]\n"
:
@@ -39,32 +95,50 @@ int main(void)
"r" (GPIO_FUNC_SIO << IO_BANK0_GPIO0_CTRL_FUNCSEL_LSB)
: "memory"
);
/// hw_clear_bits(&pads_bank0_hw->io[LED_PIN], PADS_BANK0_GPIO0_ISO_BITS);
}
/**
* @brief Clear ISO bits in PADS_BANK0 via inline assembly
*
* @details Performs a read-modify-write to clear the pad isolation
* bit, un-isolating the pad for normal operation.
*
* @retval None
*/
static void asm_clear_iso(void) {
pico_default_asm_volatile (
"ldr r2, [%0]\n" // load current register value
"bic r2, r2, %1\n" // clear the ISO bits (bit clear)
"str r2, [%0]\n" // write back
"str r2, [%0]\n" // write back
:
: "r" (&pads_bank0_hw->io[LED_PIN]),
"r" (PADS_BANK0_GPIO0_ISO_BITS)
: "r2", "memory"
);
}
// gpio_set_dir(LED_PIN, GPIO_OUT);
/// gpioc_bit_oe_put(LED_PIN, GPIO_OUT);
/**
* @brief Blink LED using coprocessor mcrr output instructions
*
* @details Toggles the LED on and off with 500ms delays using
* pico_default_asm_volatile mcrr instructions.
*
* @retval None
*/
static void asm_blink_cycle(void) {
pico_default_asm_volatile ("mcrr p0, #4, %0, %1, c0" : : "r" (LED_PIN), "r" (1));
sleep_us(500 * 1000ull);
pico_default_asm_volatile ("mcrr p0, #4, %0, %1, c0" : : "r" (LED_PIN), "r" (0));
sleep_us(500 * 1000ull);
}
int main(void) {
asm_set_oe_and_out();
asm_configure_pad();
asm_set_funcsel();
asm_clear_iso();
pico_default_asm_volatile ("mcrr p0, #4, %0, %1, c4" : : "r" (LED_PIN), "r" (GPIO_OUT));
while (true) {
// gpio_put(LED_PIN, 1);
/// gpioc_bit_out_put(LED_PIN, 1);
pico_default_asm_volatile ("mcrr p0, #4, %0, %1, c0" : : "r" (LED_PIN), "r" (1));
/// sleep_ms(500);
sleep_us(500 * 1000ull);
// gpio_put(LED_PIN, 0);
/// gpioc_bit_out_put(LED_PIN, 0);
pico_default_asm_volatile ("mcrr p0, #4, %0, %1, c0" : : "r" (LED_PIN), "r" (0));
/// sleep_ms(500);
sleep_us(500 * 1000ull);
asm_blink_cycle();
}
}