rework structure

hifive1-vp/hello/hello.c

@@ -0,0 +1,69 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "platform.h"
+#include "encoding.h"
+
+#define IOF_SPI1_MASK (0x38 | 0x4)
+int factorial(int i){
+
+	volatile int result = 1;
+	for (int ii = 1; ii <= i; ii++) {
+		result = result * ii;
+	}
+	return result;
+
+}
+
+unsigned read_adc(unsigned index){
+    unsigned char txdata[3];
+    unsigned result=0;
+    volatile int x;
+
+    txdata[0]=0x1;
+    txdata[1]=(0x8 | (index&0x7))<<4;
+    txdata[2]=0x0;
+
+    GPIO_REG(GPIO_IOF_SEL) &= ~IOF_SPI1_MASK;
+    GPIO_REG(GPIO_IOF_EN) |= IOF_SPI1_MASK;
+
+    SPI1_REG(SPI_REG_FMT) =
+            SPI_FMT_PROTO(SPI_PROTO_S) |
+            SPI_FMT_ENDIAN(SPI_ENDIAN_MSB) |
+            SPI_FMT_DIR(SPI_DIR_RX) |
+            SPI_FMT_LEN(8);
+    SPI1_REG(SPI_REG_CSID)   = 0;
+    SPI1_REG(SPI_REG_CSDEF) = 0xFFFF;
+    SPI1_REG(SPI_REG_SCKDIV)  = 7;
+    SPI1_REG(SPI_REG_SCKMODE) = SPI_SCK_PHA | SPI_SCK_POL; //shifted on the leading edge, sampled on trailing, Inactive state of SCK is logical 1
+    SPI1_REG(SPI_REG_CSMODE) = SPI_CSMODE_HOLD;
+
+    while (SPI1_REG(SPI_REG_TXFIFO) & SPI_TXFIFO_FULL) ;
+    SPI1_REG(SPI_REG_TXFIFO) = txdata[0];
+    while ((x = SPI1_REG(SPI_REG_RXFIFO)) & SPI_RXFIFO_EMPTY);
+
+    while (SPI1_REG(SPI_REG_TXFIFO) & SPI_TXFIFO_FULL) ;
+    SPI1_REG(SPI_REG_TXFIFO) = txdata[1];
+    while ((x = SPI1_REG(SPI_REG_RXFIFO)) & SPI_RXFIFO_EMPTY);
+    result = (x & 0xFF)<<8;
+
+    while (SPI1_REG(SPI_REG_TXFIFO) & SPI_TXFIFO_FULL) ;
+    SPI1_REG(SPI_REG_TXFIFO) = txdata[2];
+    while ((x = SPI1_REG(SPI_REG_RXFIFO)) & SPI_RXFIFO_EMPTY);
+    result += (x & 0xFF);
+
+    SPI1_REG(SPI_REG_CSMODE) = SPI_CSMODE_AUTO;
+    return result&0x03ff;
+}
+
+int main()
+{
+	GPIO_REG(GPIO_IOF_EN) |= 0x30000;
+	int result = factorial (10);
+	printf("Factorial of 10 is %d\n", result);
+	for(unsigned i=0; i<8; ++i)
+	    printf("ADC%u value read is %u\n", i, read_adc(i));
+	printf("End of execution");
+	return 0;
+}