diff options
Diffstat (limited to 'tmk_core/common/chibios/wait.c')
| -rw-r--r-- | tmk_core/common/chibios/wait.c | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/tmk_core/common/chibios/wait.c b/tmk_core/common/chibios/wait.c new file mode 100644 index 0000000000..c6270fd95e --- /dev/null +++ b/tmk_core/common/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; + } +}
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