add riscv64-mycpu

scripts/riscv64-mycpu.mk

@@ -0,0 +1,22 @@
+CROSS_COMPILE := riscv64-linux-gnu-
+COMMON_FLAGS  := -fno-pic -march=rv64ifd -mcmodel=medany
+CFLAGS        += $(COMMON_FLAGS) -static
+ASFLAGS       += $(COMMON_FLAGS) -O0
+LDFLAGS       += -melf64lriscv
+
+AM_SRCS := mycpu/boot/start.S \
+           mycpu/trm.c \
+		   mycpu/ioe/timer.c \
+		   mycpu/ioe/ioe.c \
+		   mycpu/ioe/input.c
+
+CFLAGS    += -fdata-sections -ffunction-sections
+LDFLAGS   += -T $(AM_HOME)/am/src/mycpu/scripts/section.ld
+LDFLAGS   += --gc-sections -e _start
+CFLAGS += -DMAINARGS=\"$(mainargs)\"
+CFLAGS += -I$(AM_HOME)/am/src/mycpu/include
+
+image: $(IMAGE).elf
+	@$(OBJDUMP) -d $(IMAGE).elf > $(IMAGE).txt
+	@echo + OBJCOPY "->" $(IMAGE_REL).bin
+	@$(OBJCOPY) -S --set-section-flags .bss=alloc,contents -O binary $(IMAGE).elf $(IMAGE).bin