build : rom rdtime

Makefile

@@ -3,26 +3,37 @@ CC = $(CROSS_COMPILER)gcc
 LD = $(CROSS_COMPILER)ld
 OBJCOPY = $(CROSS_COMPILER)objcopy
 
+# -O0
+CCFLAGS =
+
 TOOLS = tools/
 BIN2MEM = $(TOOLS)bin2mem
 
 ################### RULES ###################
-all: $(BIN2MEM) rom
+all: $(BIN2MEM) debug rom
 
+# Tools
 $(BIN2MEM): $(BIN2MEM).c
 	gcc $< -o $@ 
 
+# Debug
+debug: main.s
+
+%.s: %.c
+	$(CC) -o $@ -c $< -S $(CCFLAGS)
+
+# Main
 rom: main.bin
 	$(BIN2MEM) $<
 
-%.bin: %.elf
+main.bin: main.elf
 	$(OBJCOPY) -I elf32-little -O binary $< $@
 
-%.elf: %.o
+%.elf: %.o link.ld
 	$(LD) -o $@ -T link.ld $<
 
-%.o: %.c
-	$(CC) -o $@ -c $< -O0
+%.o: %.s
+	$(CC) -o $@ -c $< $(CCFLAGS)
 
 clean:
 	rm -f *.s *.o *.elf *.bin *.hex

link.ld

@@ -14,7 +14,9 @@
 OUTPUT_ARCH( "riscv" )
 MEMORY
 {
- MEM : ORIGIN = 0x0, LENGTH = 32K
+ IMEM : ORIGIN = 0x0, LENGTH = 16K
+ DMEM : ORIGIN = 16K, LENGTH = 16K
+ FMEM : ORIGIN = 32K, LENGTH = 200K
 }
 /*----------------------------------------------------------------------*/
 /* Sections                                                             */
@@ -25,42 +27,42 @@ SECTIONS
 {
 
   /* text: test code section */
-  . = 0x000;
+  . = 0x100;
   .text.init . :
   {
 	  *(.text.init)
-  }>MEM
+  }>IMEM
   .text :
   {
     *(.text)
-  }>MEM
+  }>IMEM
   /* data segment */
-  .data : { *(.data) }>MEM
-  .rodata : { *(.rodata) }>MEM
+  .data : { *(.data) }>DMEM
+  .rodata : { *(.rodata) }>FMEM
 
   .sdata : {
     _gp = . + 0x800;
     *(.srodata.cst16) *(.srodata.cst8) *(.srodata.cst4) *(.srodata.cst2) *(.srodata*)
     *(.sdata .sdata.* .gnu.linkonce.s.*)
-  }>MEM
+  }>DMEM
 
   /* bss segment */
   .sbss : {
     *(.sbss .sbss.* .gnu.linkonce.sb.*)
     *(.scommon)
-  }>MEM
-  .bss : { *(.bss) }>MEM
+  }>DMEM
+  .bss : { *(.bss) }>DMEM
 
   /* thread-local data segment */
   .tdata :
   {
     _tls_data = .;
     *(.tdata)
-  }>MEM
+  }>DMEM
   .tbss :
   {
     *(.tbss)
-  }>MEM
+  }>DMEM
 
 
 

main.c

-int main() {
-	int a=5, b=13;
-	int c=a+b;
-	return 0;
+int main(void)
+{
+  static int data1 = 20;
+  static int data2 = 5;
+  static int result;
+
+  result = data1 * data2;
+
+  // Store the value in a6
+  asm volatile("mv a6,%0\n\t"
+               "rdtime a5"
+    :
+    : "r" (result)
+    : "a6");
+
+  while (1) ;
+
+  return 0;
 }

tools/bin2mem.c

@@ -59,7 +59,6 @@ int main(int argc, char *argv[])
 	}
 	while(1) {
 		if(fread(w, 4, 1, fdi) <= 0) break;
-		// fdo just for easy humain read
 		fprintf(fdo, "%02hhx%02hhx%02hhx%02hhx\n", w[0], w[1], w[2], w[3]);
 		fprintf(fdo0, "%02hhx\n", w[0]);
 		fprintf(fdo1, "%02hhx\n", w[1]);