qmk_firmware/tmk_core/common/wait.h

#pragma once

#include <inttypes.h>

#ifdef __cplusplus
extern "C" {
#endif

#if defined(__ARMEL__) || defined(__ARMEB__)
#    ifndef __OPTIMIZE__
#        pragma message "Compiler optimizations disabled; wait_cpuclock() won't work as designed"
#    endif

#    define wait_cpuclock(x) wait_cpuclock_allnop(x)

#    define CLOCK_DELAY_NOP8 "nop\n\t nop\n\t nop\n\t nop\n\t   nop\n\t nop\n\t nop\n\t nop\n\t"

__attribute__((always_inline))
static inline void wait_cpuclock_allnop(unsigned int n) { /* n: 1..135 */
    /* The argument n must be a constant expression.
     * That way, compiler optimization will remove unnecessary code. */
    if (n < 1) { return; }
    if (n > 8) {
        unsigned int n8 = n/8;
        n = n - n8*8;
        switch (n8) {
        case 16: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case 15: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case 14: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case 13: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case 12: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case 11: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case 10: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case  9: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case  8: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case  7: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case  6: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case  5: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case  4: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case  3: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case  2: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case  1: asm volatile (CLOCK_DELAY_NOP8::: "memory");
        case  0: break;
        }
    }
    switch (n) {
    case 8: asm volatile ("nop"::: "memory");
    case 7: asm volatile ("nop"::: "memory");
    case 6: asm volatile ("nop"::: "memory");
    case 5: asm volatile ("nop"::: "memory");
    case 4: asm volatile ("nop"::: "memory");
    case 3: asm volatile ("nop"::: "memory");
    case 2: asm volatile ("nop"::: "memory");
    case 1: asm volatile ("nop"::: "memory");
    case 0: break;
    }
}
#endif

#if defined(__AVR__)
#    include <util/delay.h>
#    define wait_ms(ms) _delay_ms(ms)
#    define wait_us(us) _delay_us(us)
#    define wait_cpuclock(x) __builtin_avr_delay_cycles(x)
#elif defined PROTOCOL_CHIBIOS
#    include <ch.h>
#    define wait_ms(ms)                     \
        do {                                \
            if (ms != 0) {                  \
                chThdSleepMilliseconds(ms); \
            } else {                        \
                chThdSleepMicroseconds(1);  \
            }                               \
        } while (0)
#    define wait_us(us)                     \
        do {                                \
            if (us != 0) {                  \
                chThdSleepMicroseconds(us); \
            } else {                        \
                chThdSleepMicroseconds(1);  \
            }                               \
        } while (0)
#elif defined PROTOCOL_ARM_ATSAM
#    include "clks.h"
#    define wait_ms(ms) CLK_delay_ms(ms)
#    define wait_us(us) CLK_delay_us(us)
#else  // Unit tests
void wait_ms(uint32_t ms);
#    define wait_us(us) wait_ms(us / 1000)
#endif

#ifdef __cplusplus
}
#endif