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Diffstat (limited to 'tmk_core/common/chibios/wait.c')
-rw-r--r--tmk_core/common/chibios/wait.c89
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;
+ }
+} \ No newline at end of file