sdk:examples: add int_preempt

Signed-off-by: liangkangnan <liangkangnan@163.com>

sdk/examples/int_preempt/.gitignore

@@ -0,0 +1,8 @@
+# Object files
+*.o
+*.ko
+*.obj
+*.bin
+*.dump
+*.mem
+int_preempt

sdk/examples/int_preempt/Makefile

@@ -0,0 +1,20 @@
+RISCV_ARCH := rv32im
+RISCV_ABI := ilp32
+RISCV_MCMODEL := medlow
+
+
+TARGET = int_preempt
+
+
+#CFLAGS += -DSIMULATION
+#CFLAGS += -Os
+#ASM_SRCS +=
+#LDFLAGS +=
+#INCLUDES += -I.
+
+C_SRCS := \
+	main.c \
+
+
+BSP_DIR = ../../bsp
+include ../../bsp/bsp.mk

sdk/examples/int_preempt/README.md

@@ -0,0 +1 @@
+中断抢占例程。

sdk/examples/int_preempt/main.c

@@ -0,0 +1,66 @@
+#include <stdint.h>
+
+#include "../../bsp/include/timer.h"
+#include "../../bsp/include/utils.h"
+#include "../../bsp/include/rvic.h"
+#include "../../bsp/include/gpio.h"
+#include "../../bsp/include/uart.h"
+#include "../../bsp/include/xprintf.h"
+
+static volatile uint32_t count;
+
+int main()
+{
+    count = 0;
+
+    uart0_init(uart0_putc);
+
+    timer0_set_div(25);
+    timer0_set_value(10000);    // 10ms period
+    timer0_clear_int_pending();
+    timer0_set_int_enable(1);
+    timer0_set_mode_ontshot();
+    // timer0中断优先级为1
+    rvic_set_irq_prio_level(0, 1);
+    global_irq_enable();
+    rvic_irq_enable(0);
+    timer0_start(1);
+
+    // gpio0输出模式
+    gpio_set_mode(GPIO0, GPIO_MODE_OUTPUT);
+    // gpio1输入模式
+    gpio_set_mode(GPIO1, GPIO_MODE_INPUT);
+    // gpio1双沿中断
+    gpio_set_interrupt_mode(GPIO1, GPIO_INTR_DOUBLE_EDGE);
+    rvic_irq_enable(3);
+    // gpio1中断优先级为2
+    rvic_set_irq_prio_level(3, 2);
+
+    while (1) {
+        if (count == 3) {
+            gpio_set_output_toggle(GPIO0); // toggle led
+            busy_wait(500 * 1000);
+        }
+    }
+}
+
+void timer0_irq_handler()
+{
+    timer0_clear_int_pending();
+    rvic_clear_irq_pending(0);
+
+    xprintf("timer0 isr\n");
+    // GPIO0对应LED为灭
+    gpio_set_output_data(GPIO0, 1);
+
+    while (count != 3);
+}
+
+void gpio1_irq_handler()
+{
+    gpio_clear_intr_pending(GPIO1);
+    rvic_clear_irq_pending(3);
+
+    xprintf("gpio1 isr\n");
+    count++;
+}