Initial Release

divider/CMakeLists.txt

@@ -0,0 +1,12 @@
+add_executable(hello_divider
+        hello_divider.c
+        )
+
+# Pull in our pico_stdlib which pulls in commonly used features
+target_link_libraries(hello_divider pico_stdlib)
+
+# create map/bin/hex file etc.
+pico_add_extra_outputs(hello_divider)
+
+# add url via pico_set_program_url
+example_auto_set_url(hello_divider)

divider/hello_divider.c

@@ -0,0 +1,75 @@
+/**
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdio.h>
+#include "pico/stdlib.h"
+#include "hardware/divider.h"
+
+// tag::hello_divider[]
+int main() {
+    stdio_init_all();
+    printf("Hello, divider!\n");
+
+    // This is the basic hardware divider function
+    int32_t dividend = 123456;
+    int32_t divisor = -321;
+    divmod_result_t result = hw_divider_divmod_s32(dividend, divisor);
+
+    printf("%d/%d = %d remainder %d\n", dividend, divisor, to_quotient_s32(result), to_remainder_s32(result));
+
+    // Is it right?
+
+    printf("Working backwards! Result %d should equal %d!\n\n",
+           to_quotient_s32(result) * divisor + to_remainder_s32(result), dividend);
+
+    // This is the recommended unsigned fast divider for general use.
+    int32_t udividend = 123456;
+    int32_t udivisor = 321;
+    divmod_result_t uresult = hw_divider_divmod_u32(udividend, udivisor);
+
+    printf("%d/%d = %d remainder %d\n", udividend, udivisor, to_quotient_u32(uresult), to_remainder_u32(uresult));
+
+    // Is it right?
+
+    printf("Working backwards! Result %d should equal %d!\n\n",
+           to_quotient_u32(result) * divisor + to_remainder_u32(result), dividend);
+
+    // You can also do divides asynchronously. Divides will be complete after 8 cyles.
+
+    hw_divider_divmod_s32_start(dividend, divisor);
+
+    // Do something for 8 cycles!
+
+    // In this example, our results function will wait for completion.
+    // Use hw_divider_result_nowait() if you don't want to wait, but are sure you have delayed at least 8 cycles
+
+    result = hw_divider_result_wait();
+
+    printf("Async result %d/%d = %d remainder %d\n", dividend, divisor, to_quotient_s32(result),
+           to_remainder_s32(result));
+
+    // For a really fast divide, you can use the inlined versions... the / involves a function call as / always does
+    // when using the ARM AEABI, so if you really want the best performance use the inlined versions.
+    // Note that the / operator function DOES use the hardware divider by default, although you can change
+    // that behavior by calling pico_set_divider_implementation in the cmake build for your target.
+    printf("%d / %d = (by operator %d) (inlined %d)\n", dividend, divisor,
+           dividend / divisor, hw_divider_s32_quotient_inlined(dividend, divisor));
+
+    // Note however you must manually save/restore the divider state if you call the inlined methods from within an IRQ
+    // handler.
+    hw_divider_state_t state;
+    hw_divider_divmod_s32_start(dividend, divisor);
+    hw_divider_save_state(&state);
+
+    hw_divider_divmod_s32_start(123, 7);
+    printf("inner %d / %d = %d\n", 123, 7, hw_divider_s32_quotient_wait());
+
+    hw_divider_restore_state(&state);
+    int32_t tmp = hw_divider_s32_quotient_wait();
+    printf("outer divide %d / %d = %d\n", dividend, divisor, tmp);
+    return 0;
+}
+// end::hello_divider[]