119 lines
3.2 KiB
C
119 lines
3.2 KiB
C
/*
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* ===========================================================================================
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*
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* Filename: neon.c
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*
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* Description: neon useage.
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*
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* Version: Melis3.0
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* Create: 2020-03-13 10:49:09
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* Revision: none
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* Compiler: GCC:version 7.2.1 20170904 (release),ARM/embedded-7-branch revision 255204
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*
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* Author: caozilong@allwinnertech.com
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* Organization: BU1-PSW
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* Last Modified: 2020-03-20 09:04:00
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*
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* ===========================================================================================
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*/
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#include <rtthread.h>
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#include <arm_neon.h>
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#include <dfs_posix.h>
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#include <finsh_api.h>
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#include <finsh.h>
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#include <debug.h>
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#include <log.h>
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uint32_t kernel_neon_begin(void);
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void kernel_neon_end(uint32_t saved_fpexc);
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static float sum_array(float *arr, int len)
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{
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uint32_t flags;
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if (NULL == arr || len < 1)
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{
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__err("parameter error.");
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return 0;
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}
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flags = kernel_neon_begin();
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int dim4 = len >> 2; // 数组长度除4整数
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int left4 = len & 3; // 数组长度除4余数
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float32x4_t sum_vec = vdupq_n_f32(0.0);//定义用于暂存累加结果的寄存器且初始化为0
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for (; dim4 > 0; dim4--, arr += 4) //每次同时访问4个数组元素
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{
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float32x4_t data_vec = vld1q_f32(arr); //依次取4个元素存入寄存器vec
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sum_vec = vaddq_f32(sum_vec, data_vec);//ri = ai + bi 计算两组寄存器对应元素之和并存放到相应结果
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}
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float sum = vgetq_lane_f32(sum_vec, 0) + vgetq_lane_f32(sum_vec, 1) + vgetq_lane_f32(sum_vec, 2) + vgetq_lane_f32(sum_vec, 3); //将累加结果寄存器中的所有元素相加得到最终累加值
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for (; left4 > 0; left4--, arr++)
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{
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sum += (*arr) ; //对于剩下的少于4的数字，依次计算累加即可
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}
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kernel_neon_end(flags);
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return sum;
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}
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static void init_array(float *arr, int len)
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{
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int i = 0;
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for (i = 0; i < len; i ++)
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{
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arr[i] = (i * 1000) / len * 0.38;
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}
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}
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static void neon1_entry(void *para)
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{
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float array[123];
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init_array(array, 123);
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while (1)
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{
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float sum = sum_array(array, 123);
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printf("[DBG]: %s line %d, float sum %f, size %d.\n", __func__, __LINE__, sum, sizeof(__simd64_float32_t));
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}
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}
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static void neon2_entry(void *para)
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{
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float array[255];
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init_array(array, 255);
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while (1)
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{
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float sum = sum_array(array, 255);
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printf("[DBG]: %s line %d, float sum %f, size %d.\n", __func__, __LINE__, sum, sizeof(__simd64_float32_t));
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}
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}
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static void armneon_entry(void)
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{
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rt_thread_t neon_thread1, neon_thread2;
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rt_enter_critical();
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neon_thread1 = rt_thread_create("neon1", neon1_entry, RT_NULL, 0x1000, 1, 10);
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RT_ASSERT(neon_thread1 != RT_NULL);
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rt_thread_startup(neon_thread1);
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neon_thread2 = rt_thread_create("neon2", neon2_entry, RT_NULL, 0x1000, 1, 10);
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RT_ASSERT(neon_thread2 != RT_NULL);
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rt_thread_startup(neon_thread2);
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rt_exit_critical();
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return;
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}
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static int cmd_armneon(int argc, const char **argv)
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{
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armneon_entry();
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return 0;
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}
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FINSH_FUNCTION_EXPORT_ALIAS(cmd_armneon, __cmd_armneon, armneon test);
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