diff options
Diffstat (limited to 'platforms/chibios/_wait.c')
| -rw-r--r-- | platforms/chibios/_wait.c | 89 | 
1 files changed, 89 insertions, 0 deletions
| diff --git a/platforms/chibios/_wait.c b/platforms/chibios/_wait.c new file mode 100644 index 0000000000..1fbea2dd5e --- /dev/null +++ b/platforms/chibios/_wait.c @@ -0,0 +1,89 @@ +/* Copyright 2021 QMK + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program.  If not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef __OPTIMIZE__ +#    pragma message "Compiler optimizations disabled; wait_cpuclock() won't work as designed" +#endif + +#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(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; +    } +} | 
