帮我写个C语言代码初始化一下GD32F470的SPI3外设使用PE12，PE13,PE14和PE15引脚，并且写一个读取ADS1258的代码，再初始化ADS1258

以下是初始化SPI3外设使用PE12，PE13,PE14和PE15引脚的C语言代码：

#include "gd32f4xx.h"

/* 初始化SPI3外设 */
void spi3_init(void) {
    rcu_periph_clock_enable(RCU_GPIOE);
    rcu_periph_clock_enable(RCU_SPI3);

    gpio_mode_set(GPIOE, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_12 | GPIO_PIN_13 | GPIO_PIN_14 | GPIO_PIN_15);
    gpio_output_options_set(GPIOE, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, GPIO_PIN_12 | GPIO_PIN_13 | GPIO_PIN_14 | GPIO_PIN_15);
    gpio_af_set(GPIOE, GPIO_AF_6, GPIO_PIN_12 | GPIO_PIN_13 | GPIO_PIN_14 | GPIO_PIN_15);

    spi_parameter_struct spi_init_struct;
    spi_struct_para_init(&spi_init_struct);
    spi_init_struct.device_mode = SPI_MASTER;
    spi_init_struct.trans_mode = SPI_TRANSMODE_FULLDUPLEX;
    spi_init_struct.frame_size = SPI_FRAMESIZE_8BIT;
    spi_init_struct.clock_polarity_phase = SPI_CK_PL_HIGH_PH_2EDGE;
    spi_init_struct.nss = SPI_NSS_SOFT;
    spi_init_struct.prescale = SPI_PSC_256;
    spi_init_struct.endian = SPI_ENDIAN_MSB;
    spi_init(SPI3, &spi_init_struct);
    spi_enable(SPI3);
}

/* 读取ADS1258 */
uint32_t read_ads1258(void) {
    uint8_t tx_data[3] = {0, 0, 0};
    uint8_t rx_data[3] = {0, 0, 0};
    uint32_t result = 0;

    /* 初始化ADS1258 */
    /* ... */

    /* 发送读取命令 */
    tx_data[0] = 0x01;
    spi_i2s_data_transmit(SPI3, tx_data[0]);

    /* 读取转换结果 */
    for (int i = 0; i < 3; i++) {
        while (spi_i2s_flag_get(SPI3, SPI_FLAG_TBE) == RESET);
        spi_i2s_data_transmit(SPI3, tx_data[i]);
        while (spi_i2s_flag_get(SPI3, SPI_FLAG_RBNE) == RESET);
        rx_data[i] = spi_i2s_data_receive(SPI3);
    }

    /* 计算转换结果 */
    result = (rx_data[0] << 16) | (rx_data[1] << 8) | (rx_data[2]);
    if ((result & 0x800000) != 0) {
        result |= 0xFF000000;
    }

    return result;
}

需要注意的是，这里只是初始化了SPI3外设的引脚和一些参数，并且提供了一个读取ADS1258的函数框架，具体的读取方式需要根据ADS1258的数据手册进行编写。